<PAGE>
                                 OCCULOGIX, INC.

                              8,400,000 Shares(1)
                                  Common Stock
                               ($0.001 par value)

                             Underwriting Agreement


                                                              New York, New York
                                                              December [ ], 2004


Citigroup Global Markets Inc.
SG Cowen & Co., LLC
ThinkEquity Partners LLC
As Representatives of the several Underwriters,
c/o Citigroup Global Markets Inc.
388 Greenwich Street
New York, New York  10013


Ladies and Gentlemen:

        OccuLogix, Inc., a corporation organized under the laws of the State of
Delaware (the "Company"), proposes to sell to the several underwriters named in
Schedule I hereto (the "Underwriters"), for whom you (the "Representatives") are
acting as representatives, 5,600,000 shares of Common Stock, $0.001 par value
per share ("Common Stock"), of the Company and the persons named in Schedule II
hereto (the "Selling Stockholders") propose to sell to the several Underwriters
2,800,000 shares of Common Stock (said shares to be issued and sold by the
Company and shares to be sold by the Selling Stockholders collectively being
hereinafter called the "Underwritten Securities"). The Selling Stockholders
named in Schedule II hereto also propose to grant to the Underwriters an option
(the "Over-Allotment Option") to purchase up to 1,260,000 additional shares of
Common Stock to cover over-allotments (the "Option Securities"; the Option
Securities, together with the Underwritten Securities, being hereinafter called
the "Securities"). To the extent there are no additional Underwriters listed on
Schedule I other than you, the term Representatives as used herein shall mean
you, as Underwriters, and the terms Representatives and Underwriters shall mean
either the singular or plural as the context requires. In addition, to the
extent that there is not more than one Selling Stockholder named in Schedule II,
the term Selling Stockholder shall mean either the singular or plural. The use
of the neuter in this Agreement shall include the feminine and masculine
wherever appropriate. Certain terms used herein are defined in Section 17
hereof.

------------------------------

(1)  Plus an option to purchase from the Selling Stockholders up to 1,260,000
     additional Securities to cover over-allotments.



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        As part of the offering contemplated by this Agreement, Citigroup Global
Markets Inc. has agreed to reserve out of the Securities set forth opposite its
name on Schedule I to this Agreement, up to 420,000 shares of Common Stock, for
sale to the Company's employees, officers, and directors and certain of their
friends and family (collectively, "Participants"), as set forth in the
Prospectus under the heading "Underwriting" (the "Directed Share Program"). The
Securities to be sold by Citigroup Global Markets Inc. pursuant to the Directed
Share Program (the "Directed Shares") will be sold by Citigroup Global Markets
Inc. pursuant to this Agreement at the public offering price. Any Directed
Shares not orally confirmed for purchase by any Participants by 8:00 a.m. New
York City time on the business day following the date on which this Agreement is
executed will be offered to the public by Citigroup Global Markets Inc. as set
forth in the Prospectus.

        1. Representations and Warranties.


                (i) The Company and each of the Selling Stockholders listed in
Schedule II and identified as Major Selling Stockholders (the "Major Selling
Stockholders") jointly and severally represent and warrant to, and agree with,
each Underwriter as set forth below in this Section 1.

                        (a) The Company has prepared and filed with the
        Commission a registration statement (file number 333-118204) on Form
        S-1, including a related preliminary prospectus, for registration under
        the Act of the offering and sale of the Securities. The Company may have
        filed one or more amendments thereto, including a related preliminary
        prospectus, each of which has previously been furnished to you. The
        Company will next file with the Commission one of the following: either
        (1) prior to the Effective Date of such registration statement, a
        further amendment to such registration statement (including the form of
        final prospectus) or (2) after the Effective Date of such registration
        statement, a final prospectus in accordance with Rules 430A and 424(b).
        In the case of clause (2), the Company has included in such registration
        statement, as amended at the Effective Date, all information (other than
        Rule 430A Information) required by the Act and the rules thereunder to
        be included in such registration statement and the U.S. Prospectus. As
        filed, such amendment and form of final prospectus, or such final
        prospectus, shall contain all Rule 430A Information, together with all
        other such required information, and, except to the extent the
        Representatives shall agree in writing to a modification, shall be in
        all substantive respects in the form furnished to you prior to the
        Execution Time or, to the extent not completed at the Execution Time,
        shall contain only such specific additional information and other
        changes (beyond that contained in the latest Preliminary U.S.
        Prospectus) as the Company has advised you, prior to the Execution Time,
        will be included or made therein.

                        (b) The Company shall comply with, to the satisfaction
        of the Underwriters, all of the Canadian Securities Laws required to be
        complied with by the Company to qualify the Distribution of the
        Over-Allotment Option and the Securities in each of the provinces of
        Canada (the "Canadian Qualifying Jurisdictions") by or through the
        Underwriters, their affiliates and other properly registered Selling
        Firms who have complied with the relevant provisions of Canadian
        Securities Laws. To that end, the Company has prepared and filed with
        the Ontario Securities Commission (the "OSC"), as




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        principal regulator under MRRS, and the other Canadian Securities
        Commissions, a preliminary base PREP prospectus relating to the
        Over-Allotment Option and the Securities in the English and French
        languages (the "Canadian Preliminary Prospectus"). The Canadian
        Preliminary Prospectus has been filed with the Canadian Securities
        Commissions in each of the Canadian Qualifying Jurisdictions pursuant to
        National Policy 43-201. The Company has obtained a preliminary MRRS
        decision document issued by the OSC, in its capacity as principal
        regulator under MRRS, evidencing that preliminary receipts of the
        Canadian Securities Commissions in each of the Canadian Qualifying
        Jurisdictions have been issued in respect of the Canadian Preliminary
        Prospectus. The Company may have filed one or more amendments to the
        Canadian Preliminary Prospectus, each of which has previously been
        furnished to you. The Company has also prepared and filed with the OSC
        and the other Canadian Securities Commissions a final base PREP
        prospectus relating to the Over-Allotment Option and the Securities in
        the English and French Languages omitting the PREP information (as
        hereinafter defined) (the "Canadian Final Prospectus") in accordance
        with the rules and procedures established pursuant to National
        Instrument 44-103 for the pricing of securities after the final receipt
        for a prospectus has been obtained (the "PREP Procedures") and has
        obtained a final MRRS decision document issued by the OSC, in its
        capacity as principal regulator under MRRS, evidencing that final
        receipts of the Canadian Securities Commissions in each of the Canadian
        Qualifying Jurisdictions have been issued in respect of the Canadian
        Final Prospectus. The Company will prepare and file, promptly after the
        execution and delivery of this Agreement, with the OSC and the other
        Canadian Securities Commissions, in accordance with the PREP Procedures,
        a supplemented prospectus in the English and French languages setting
        forth the PREP Information (the "Canadian Supplemental PREP
        Prospectus"). The Company shall co-operate in all respects with the
        Underwriters to allow and assist the Underwriters to participate in the
        preparation of the Canadian Supplemental PREP Prospectus, which shall be
        in a form satisfactory to the Underwriters. The information included in
        the Canadian Supplemental PREP Prospectus that is omitted from the
        Canadian Final Prospectus but that is deemed under the PREP Procedures
        to be incorporated by reference into the Canadian Final Prospectus on
        the date of the Canadian Supplemental PREP Prospectus is referred to as
        the "PREP information". Collectively, the Canadian Final Prospectus, as
        supplemented by the Canadian Supplemental PREP Prospectus, is referred
        to as the "Canadian Prospectus". Collectively, the "Canadian Prospectus"
        and the "U.S. Prospectus" are referred to as the "Prospectus".

                        (c) On the Effective Date, the Registration Statement
        did or will, and when the U.S. Prospectus is first filed (if required)
        in accordance with Rule 424(b) and on the Closing Date (as defined
        herein) and on any date on which Option Securities are purchased, if
        such date is not the Closing Date (a "settlement date"), the U.S.
        Prospectus (and any supplements thereto) will, comply in all material
        respects with the applicable requirements of the Act and the rules
        thereunder; on the Effective Date and at the Execution Time, the
        Registration Statement did not or will not contain any untrue statement
        of a material fact or omit to state any material fact required to be
        stated therein or necessary in order to make the statements therein not
        misleading; and, on the Effective Date, the U.S. Prospectus, if not
        filed pursuant to Rule 424(b), will not, and on the date of any filing
        pursuant to Rule 424(b) and on the Closing Date and any settlement date,
        the



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<PAGE>

        U.S. Prospectus (together with any supplement thereto) will not, include
        any untrue statement of a material fact or omit to state a material fact
        necessary in order to make the statements therein, in the light of the
        circumstances under which they were made, not misleading. All
        information and statements contained in the Canadian Final Prospectus,
        as supplemented by the Canadian Supplemental PREP Prospectus, will, on
        the date of filing of the Canadian Supplemental PREP Prospectus and on
        the Closing Date and on any date on which the Option Securities are
        purchased if such date is not the Closing Date, be true and correct in
        all material respects and contain no misrepresentation (as that term is
        defined under Canadian Securities Laws) and constitute full, true and
        plain disclosure of all material facts relating to the Company, the
        Over-Allotment Option and the Securities, and no material fact or
        information has been omitted therefrom which is required to be stated
        therein or is necessary to make any statement or information contained
        therein not false or misleading in light of the circumstances in which
        it was made, and the Canadian Final Prospectus, as supplemented by the
        Canadian Supplemental PREP Prospectus, will, on the date of filing of
        the Canadian Supplemental PREP Prospectus and on the Closing Date,
        comply in all material respects with Canadian Securities Laws; provided,
        however, that the Company and the Major Selling Stockholders make no
        representations or warranties as to the information contained in or
        omitted from the Registration Statement, the U.S. Prospectus (or any
        supplement thereto), the Canadian Final Prospectus or the Canadian
        Supplemental PREP Prospectus in reliance upon and in conformity with
        information furnished in writing to the Company by or on behalf of any
        Underwriter through the Representatives specifically for inclusion in
        the Registration Statement, the U.S. Prospectus (or any supplement
        thereto), the Canadian Final Prospectus or the Canadian Supplemental
        PREP Prospectus.

                        (d) Each of the Company and its subsidiaries has been
        duly organized and is validly existing as a corporation or partnership
        (as applicable) in good standing under the laws of the jurisdiction in
        which it is chartered or organized with full corporate or partnership
        (as applicable) power and authority to own or lease, as the case may be,
        and to operate its properties and conduct its business as described in
        the Prospectus, and is duly qualified to do business as a foreign
        corporation or partnership (as applicable) and is in good standing under
        the laws of each jurisdiction which requires such qualification, except
        where the failure to be so qualified or in good standing would not
        reasonably be expected to have a material adverse effect on the
        condition (financial or otherwise), prospects, earnings, business or
        properties of the Company and its subsidiaries taken as a whole, whether
        or not arising from transactions in the ordinary course of business (a
        "Material Adverse Effect"), except as set forth in or contemplated in
        the Prospectus (exclusive of any supplement thereto).

                        (e) All the outstanding shares of capital stock or other
        equity interests of each subsidiary have been duly and validly
        authorized and issued and are fully paid and nonassessable, and, except
        as otherwise set forth in the Prospectus, all outstanding shares of
        capital stock or other equity interests of the subsidiaries are owned by
        the Company either directly or through wholly owned subsidiaries free
        and clear of any perfected security interest or any other security
        interests, claims, liens or encumbrances.



                                      -4-
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                        (f) The Company's authorized equity capitalization is as
        set forth in the Prospectus; the capital stock of the Company conforms
        in all material respects to the description thereof contained in the
        Prospectus; the outstanding shares of Common Stock (including the
        Securities being sold hereunder by the Selling Stockholders) have been
        duly and validly authorized and issued and are fully paid and
        nonassessable; the Securities being sold hereunder by the Company have
        been duly and validly authorized, and, when issued and delivered to and
        paid for by the Underwriters pursuant to this Agreement, will be fully
        paid and nonassessable; the Securities have been approved for quotation
        on the Nasdaq National Market, subject to official notice of issuance
        and evidence of satisfactory distribution; the Securities have been
        conditionally approved for listing on the TSX, subject only to
        compliance with minimum distribution requirements and the Company
        providing to the TSX certain required routine documentation; the
        certificates for the Securities have been duly approved and adopted by
        the Company and are in valid and sufficient form and comply with the
        requirements of the TSX and Nasdaq National Market; the holders of
        outstanding shares of capital stock of the Company are not entitled to
        preemptive or other rights to subscribe for the Common Stock; and,
        except as set forth in the Prospectus, no options, warrants or other
        rights to purchase, agreements or other obligations to issue, or rights
        to convert any obligations into or exchange any securities for, shares
        of capital stock of or ownership interests in the Company are
        outstanding.


                        (g) There is no franchise, contract or other document of
        a character required to be described in the Registration Statement or
        Prospectus, or to be filed as an exhibit thereto, which is not described
        or filed as required; and the statements in the Prospectus under the
        headings "Risk Factors - Even if we complete MIRA-1, we may not receive
        FDA approval to market the RHEO System in the United States," "Risk
        Factors - We currently depend on single sources for key components of
        the RHEO System. The loss of any of these sources could delay our
        clinical trials or prevent or delay commercialization of the RHEO
        System," "Risk Factors - Our supply agreement with Asahi Medical
        requires us to transfer the FDA approval of the RHEO System to it upon
        receipt which will limit our control of the FDA approval," "Risk Factors
        - If we or our suppliers fail to comply with the extensive regulatory
        requirements to which we and the RHEO System are subject, the RHEO
        System could be subject to restrictions or withdrawals from the market
        and we could be subject to penalties," "Risk Factors - Future sales of
        our common stock could reduce our stock price," "Risk Factors - We have
        entered into a number of related party transactions with suppliers,
        creditors, stockholders and other parties, each of which may have
        interests which conflict with those of our public stockholders,"
        "Business - Clinical Studies," "Business - Supplier Relationships,"
        "Business - Government Regulation," "Reorganization," "Management,"
        "Certain Relationships and Related Party Transactions," "Description of
        Capital Stock" and "Shares Eligible for Future Sale," insofar as such
        statements summarize legal matters, agreements, documents or proceedings
        discussed therein, are accurate and fair summaries in all material
        respects of such legal matters, agreements, documents or proceedings.

                        (h) This Agreement has been duly authorized, executed
        and delivered by the Company.



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                        (i) The Company is not and, after giving effect to the
        offering and sale of the Securities and the application of the proceeds
        thereof as described in the Prospectus, will not be an "investment
        company" as defined in the Investment Company Act of 1940, as amended.

                        (j) No consent, approval, authorization, filing with or
        order of any court or Governmental Authority is required in connection
        with the transactions contemplated herein, except for the filing of the
        Canadian Supplemental PREP Prospectus with the Canadian Securities
        Commissions and except for such as have been obtained under the Act,
        under Canadian Securities Laws and such as may be required under the
        blue sky laws of any jurisdiction in connection with the purchase and
        distribution of the Securities by the Underwriters in the manner
        contemplated herein and in the Prospectus.

                        (k) Neither the issue and sale of the Securities nor the
        consummation of any other of the transactions herein contemplated nor
        the fulfillment of the terms hereof will conflict with, result in a
        breach or violation of, or imposition of any lien, charge or encumbrance
        upon any property or assets of the Company or any of its subsidiaries
        pursuant to, (i) the charter or by-laws of the Company or any of its
        subsidiaries, (ii) the terms of any indenture, contract, lease,
        mortgage, deed of trust, note agreement, loan agreement or other
        agreement, obligation, condition, covenant or instrument to which the
        Company or any of its subsidiaries is a party or bound or to which its
        or their property is subject, or (iii) any statute, law, rule,
        regulation, judgment, order or decree applicable to the Company or any
        of its subsidiaries of any court, regulatory body, administrative
        agency, Governmental Authority, arbitrator or other authority having
        jurisdiction over the Company or any of its subsidiaries or any of its
        or their properties.

                        (l) Except as disclosed in the prospectus, no holders of
        securities of the Company have rights to the registration of such
        securities under the Registration Statement which have not been
        satisfied or waived.

                        (m) The consolidated historical financial statements of
        the Company and its consolidated subsidiaries included in the Prospectus
        and the Registration Statement present fairly in all material respects
        the financial condition, results of operations and cash flows of the
        Company as of the dates and for the periods indicated, comply as to form
        in all material respects with the applicable accounting requirements of
        the Act and the Canadian Securities Laws, have been prepared in
        conformity with U.S. generally accepted accounting principles applied on
        a consistent basis throughout the periods involved (except as otherwise
        noted therein) and have been reconciled to Canadian generally accepted
        accounting principles. The selected financial data set forth under the
        caption "Selected Consolidated Financial Data" in the Prospectus and the
        Registration Statement fairly present in all material respects, on the
        basis stated in the Prospectus and the Registration Statement, the
        information included therein. The pro forma financial statements
        included in the Prospectus and the Registration Statement include
        assumptions that provide a reasonable basis for presenting the
        significant effects directly attributable to the transactions and events
        described therein, the related pro forma




                                      -6-
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        adjustments give appropriate effect to those assumptions, and the pro
        forma adjustments reflect the proper application of those adjustments to
        the historical financial statement amounts in the pro forma financial
        statements included in the Prospectus and the Registration Statement.
        The pro forma financial statements included in the Prospectus and the
        Registration Statement comply as to form in all material respects with
        the applicable accounting requirements of Regulation S-X under the Act
        and the Canadian Securities Laws and the pro forma adjustments have been
        properly applied to the historical amounts in the compilation of those
        statements.

                        (n) No action, suit or proceeding by or before any court
        or Governmental Authority or any arbitrator involving the Company or any
        of its subsidiaries or its or their property is pending or, to the best
        knowledge of the Company, threatened that (i) could reasonably be
        expected to have a material adverse effect on the performance of this
        Agreement or the consummation of any of the transactions contemplated
        hereby or (ii) could reasonably be expected to have a Material Adverse
        Effect, except as set forth in or contemplated in the Prospectus
        (exclusive of any supplement thereto).

                        (o) Each of the Company and each of its subsidiaries
        owns or leases all such properties as are necessary to the conduct of
        its operations as presently conducted, except for any such properties
        that the failure to own or lease could not reasonably be expected to
        have a Material Adverse Effect, except as set forth in or contemplated
        in the Prospectus (exclusive of any supplement thereto).

                        (p) Neither the Company nor any subsidiary is in
        violation or default of any provision of (i) its charter or bylaws, (ii)
        the terms of any indenture, contract, lease, mortgage, deed of trust,
        note agreement, loan agreement or other agreement, obligation,
        condition, covenant or instrument to which it is a party or bound or to
        which its property is subject, or (iii) any statute, law, rule,
        regulation, judgment, order or decree of any court, regulatory body,
        administrative agency, Governmental Authority, arbitrator or other
        authority having jurisdiction over the Company or such subsidiary or any
        of its properties, as applicable, except, in the case of clauses (ii) or
        (iii) above, for violations or defaults as would not reasonably be
        expected to have a Material Adverse Effect, except as set forth in or
        contemplated in the Prospectus (exclusive of any supplement thereto).

                        (q) Ernst & Young LLP, who has certified certain
        financial statements of the Company and its consolidated subsidiaries
        and delivered its report with respect to the audited consolidated
        financial statements included in the Prospectus, is an independent
        registered public accounting firm with respect to the Company within the
        meaning of the Act and the applicable published rules and regulations
        thereunder and are independent public accountants as required under
        Canadian Securities Laws, and there has not been any disagreement
        (within the meaning of National Policy Statement No. 31) with the
        present or any former accountants of the Company and Deloitte & Touche
        LLP, at the time they were the Company's accountants, were independent
        public accountants under applicable law.



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                        (r) There are no transfer taxes or other similar fees or
        charges under the laws of Canada or any political subdivision thereof,
        U.S. federal law or the laws of any state, or any political subdivision
        thereof, required to be paid in connection with the execution and
        delivery of this Agreement or the issuance by the Company or sale by the
        Company of the Securities.

                        (s) Each of the Company and its subsidiaries has filed
        all Tax Returns that are required to be filed or has requested
        extensions thereof (except in any case in which the failure so to file
        would not have a Material Adverse Effect, except as set forth in or
        contemplated in the Prospectus (exclusive of any supplement thereto))
        and has paid all Taxes required to be paid by it and any other
        assessment, fine or penalty levied against it, to the extent that any of
        the foregoing is due and payable, except for any such assessment, fine
        or penalty that is currently being contested in good faith or as would
        not have a Material Adverse Effect, except as set forth in or
        contemplated in the Prospectus (exclusive of any supplement thereto).

                        (t) No labor problem or dispute with the employees of
        the Company or any of its subsidiaries exists or, to the knowledge of
        the Company, is threatened or imminent, and the Company is not aware of
        any existing or imminent labor disturbance by the employees of any of
        its or its subsidiaries' principal suppliers, contractors or customers,
        that could reasonably be expected to have a Material Adverse Effect,
        except as set forth in or contemplated in the Prospectus (exclusive of
        any supplement thereto).

                        (u) The Company and each of its subsidiaries are insured
        by insurers of recognized financial responsibility against such losses
        and risks and in such amounts as are prudent in the businesses in which
        they are engaged; all policies of insurance and fidelity or surety bonds
        insuring the Company or any of its subsidiaries or their respective
        businesses, assets, employees, officers and directors are in full force
        and effect; the Company and its subsidiaries are in compliance with the
        terms of such policies and instruments in all material respects; and
        there are no claims by the Company or any of its subsidiaries under any
        such policy or instrument as to which any insurance company is denying
        liability or defending under a reservation of rights clause; neither the
        Company nor any such subsidiary has been refused any insurance coverage
        sought or applied for; and neither the Company nor any such subsidiary
        has any reason to believe that it will not be able to renew its existing
        insurance coverage as and when such coverage expires or to obtain
        similar coverage from similar insurers as may be necessary to continue
        its business at a cost that would not have a Material Adverse Effect,
        except as set forth in or contemplated in the Prospectus (exclusive of
        any supplement thereto).

                        (v) No subsidiary of the Company is currently
        prohibited, directly or indirectly, from paying any dividends to the
        Company, from making any other distribution on such subsidiary's capital
        stock, from repaying to the Company any loans or advances to such
        subsidiary from the Company or from transferring any of such
        subsidiary's property or assets to the Company or any other subsidiary
        of the Company, except as described in or contemplated by the Prospectus
        (exclusive of any supplement thereto).



                                      -8-
<PAGE>

                        (w) The Company and its subsidiaries possess all
        licenses, certificates, permits and other authorizations issued by the
        appropriate federal, state, provincial, municipal or foreign regulatory
        authorities necessary to conduct their respective businesses, except for
        any which the failure to possess could not reasonably be expected to
        have a Material Adverse Effect, except as set forth in or contemplated
        in the Prospectus (exclusive of any supplement thereto), and neither the
        Company nor any such subsidiary has received any notice of proceedings
        relating to the revocation or modification of any such certificate,
        authorization or permit which, singly or in the aggregate, if the
        subject of an unfavorable decision, ruling or finding, would have a
        Material Adverse Effect, except as set forth in or contemplated in the
        Prospectus (exclusive of any supplement thereto).

                        (x) The Company and each of its subsidiaries maintain a
        system of internal accounting controls sufficient to provide reasonable
        assurance that (i) transactions are executed in accordance with
        management's general or specific authorizations; (ii) transactions are
        recorded as necessary to permit preparation of financial statements in
        conformity with U.S. generally accepted accounting principles and to
        maintain asset accountability; (iii) access to assets is permitted only
        in accordance with management's general or specific authorization; and
        (iv) the recorded accountability for assets is compared with the
        existing assets at reasonable intervals and appropriate action is taken
        with respect to any differences.

                        (y) The Company has not taken, directly or indirectly,
        any action designed to or that would constitute or that might reasonably
        be expected to cause or result in, under the Exchange Act or otherwise,
        stabilization or manipulation of the price of any security of the
        Company to facilitate the sale or resale of the Securities.

                        (z) The Company and its subsidiaries are (i) in
        compliance with any and all applicable foreign, federal, state and local
        laws and regulations relating to the protection of human health and
        safety, the environment or hazardous or toxic substances or wastes,
        pollutants or contaminants ("Environmental Laws"), (ii) have received
        and are in compliance with all permits, licenses or other approvals
        required of them under applicable Environmental Laws to conduct their
        respective businesses and (iii) have not received notice of any actual
        or potential liability under any environmental law, except where such
        non-compliance with Environmental Laws, failure to receive required
        permits, licenses or other approvals, or liability would not,
        individually or in the aggregate, have a Material Adverse Effect, except
        as set forth in or contemplated in the Prospectus (exclusive of any
        supplement thereto). Except as set forth in the Prospectus, neither the
        Company nor any of the subsidiaries has been named as a "potentially
        responsible party" under the Comprehensive Environmental Response,
        Compensation, and Liability Act of 1980, as amended.

                        (aa) In the ordinary course of its business, the Company
        periodically reviews the effect of Environmental Laws on the business,
        operations and properties of the Company and its subsidiaries, in the
        course of which it identifies and evaluates associated costs and
        liabilities (including, without limitation, any capital or operating
        expenditures required for clean-up, closure of properties or compliance
        with




                                      -9-
<PAGE>

        Environmental Laws, or any permit, license or approval, any related
        constraints on operating activities and any potential liabilities to
        third parties). On the basis of such review, the Company has reasonably
        concluded that such associated costs and liabilities would not, singly
        or in the aggregate, have a Material Adverse Effect, except as set forth
        in or contemplated in the Prospectus (exclusive of any supplement
        thereto).

                        (bb) The minimum funding standard under Section 302 of
        the Employee Retirement Income Security Act of 1974, as amended, and the
        regulations and published interpretations thereunder ("ERISA"), has been
        satisfied by each "pension plan" (as defined in Section 3(2) of ERISA)
        which has been established or maintained by the Company and/or one or
        more of its subsidiaries, and the trust forming part of each such plan
        which is intended to be qualified under Section 401 of the U.S. Internal
        Revenue Code of 1986, as amended, is so qualified; each of the Company
        and its subsidiaries has fulfilled its obligations, if any, under
        Section 515 of ERISA; neither the Company nor any of its subsidiaries
        maintains or is required to contribute to a "welfare plan" (as defined
        in Section 3(l) of ERISA) which provides retiree or other
        post-employment welfare benefits or insurance coverage (other than
        "continuation coverage" (as defined in Section 602 of ERISA)); each
        pension plan and welfare plan established or maintained by the Company
        and/or one or more of its subsidiaries is in compliance in all material
        respects with the currently applicable provisions of ERISA; and neither
        the Company nor any of its subsidiaries has incurred or could reasonably
        be expected to incur any withdrawal liability under Section 4201 of
        ERISA, any liability under Section 4062, 4063, or 4064 of ERISA, or any
        other liability under Title IV of ERISA.

                        (cc) There is and has been no failure on the part of the
        Company and any of the Company's directors or officers, in their
        capacities as such, to comply with any applicable provision of the
        Sarbanes Oxley Act of 2002 and the rules and regulations promulgated in
        connection therewith (the "Sarbanes Oxley Act"), including Section 402
        related to loans and Sections 302 and 906 related to certifications.

                        (dd) Neither the Company nor any of its subsidiaries
        nor, to the knowledge of the Company, any director, officer, agent,
        employee or affiliate of the Company or any of its subsidiaries is aware
        of or has taken any action, directly or indirectly, that would result in
        a violation by such persons of the FCPA, including, without limitation,
        making use of the mails or any means or instrumentality of interstate
        commerce corruptly in furtherance of an offer, payment, promise to pay
        or authorization of the payment of any money, or other property, gift,
        promise to give, or authorization of the giving of anything of value to
        any "foreign official" (as such term is defined in the FCPA) or any
        non-U.S. political party or official thereof or any candidate for
        non-U.S. political office, in contravention of the FCPA and the Company,
        its subsidiaries and, to the knowledge of the Company, its affiliates
        have conducted their businesses in compliance with the FCPA and have
        instituted and maintain policies and procedures designed to ensure, and
        which are reasonably expected to continue to ensure, continued
        compliance therewith.

                        "FCPA" means Foreign Corrupt Practices Act of 1977, as
        amended, and the rules and regulations thereunder.



                                      -10-
<PAGE>

                        (ee) The operations of the Company and its subsidiaries
        are and have been conducted at all times in compliance with applicable
        financial recordkeeping and reporting requirements of the Currency and
        Foreign Transactions Reporting Act of 1970, as amended, the money
        laundering statutes of all jurisdictions, the rules and regulations
        thereunder and any related or similar rules, regulations or guidelines,
        issued, administered or enforced by any Governmental Authority
        (collectively, the "Money Laundering Laws") and no action, suit or
        proceeding by or before any court or Governmental Authority or any
        arbitrator involving the Company or any of its subsidiaries with respect
        to the Money Laundering Laws is pending or, to the best knowledge of the
        Company, threatened.

                        (ff) Neither the Company nor any of its subsidiaries
        nor, to the knowledge of the Company, any director, officer, agent,
        employee or affiliate of the Company or any of its subsidiaries is
        currently subject to any U.S. sanctions administered by the Office of
        Foreign Assets Control of the U.S. Treasury Department ("OFAC"); and the
        Company will not directly or indirectly use the proceeds of the
        offering, or lend, contribute or otherwise make available such proceeds
        to any subsidiary, joint venture partner or other person or entity, for
        the purpose of financing the activities of any person currently subject
        to any U.S. sanctions administered by OFAC.

                        (gg) The subsidiaries listed on Annex A attached hereto
        are the only significant subsidiaries of the Company as defined by Rule
        1-02 of Regulation S-X.

                        (hh) The Company and its subsidiaries own, possess,
        license or have other rights to use, on reasonable terms, all patents,
        patent applications, trademark and service marks, trademark and service
        mark registrations, trade names, copyrights, licenses, inventions, trade
        secrets, technology, know-how and other intellectual property
        (collectively, the "Intellectual Property") necessary for the conduct of
        the Company's business as now conducted or as proposed in the Prospectus
        to be conducted, except for any which the failure to own, possess,
        license or have the rights to use could not reasonably be expected to
        have a Material Adverse Effect, except as set forth in or contemplated
        in the Prospectus (exclusive of any supplement thereto). Except as set
        forth in the Prospectus under the caption "Business-Patents and
        Proprietary Rights," (a) there are no rights of third parties to any
        such Intellectual Property; (b) there is no material infringement by
        third parties of any such Intellectual Property; (c) there is no pending
        or, to the Company's knowledge, threatened action, suit, proceeding or
        claim by others challenging the Company's rights in or to any such
        Intellectual Property, and the Company is unaware of any facts which
        would form a reasonable basis for any such claim; (d) there is no
        pending or, to the Company's knowledge, threatened action, suit,
        proceeding or claim by others challenging the validity or scope of any
        such Intellectual Property and the Company is unaware of any facts which
        would form a reasonable basis for any such claim; (e) there is no
        pending or, to the Company's knowledge, threatened action, suit,
        proceeding or claim by others that the Company infringes or otherwise
        violates any patent, trademark, copyright, trade secret or other
        proprietary rights of others, and the Company is unaware of any other
        fact which would form a reasonable basis for any such claim; (f) there
        is no U.S. patent which contains claims that dominate or may dominate
        any Intellectual Property described in the Prospectus as being owned by


                                      -11-
<PAGE>

        or licensed to the Company or that interferes with the issued or pending
        claims of any such Intellectual Property; and (g) there is no prior art
        of which the Company is aware that may render any U.S. patent held or
        licensed by the Company invalid or any U.S. patent application held or
        licensed by the Company unpatentable.

                        (ii) Each of the current employees of the Company,
        including for greater certainty each of the officers of the Company, has
        entered into an agreement with the Company assigning to the Company all
        intellectual property rights (including moral rights) to which such
        employee may have a claim that were created during the term of
        employment of the employee, and each current employee of the Company,
        including for greater certainty each of the officers of the Company, has
        entered into a reasonably appropriate confidentiality agreement with the
        Company.

                        (jj) The statements contained in the Prospectus under
        the captions "Risk Factors -- Our patents may not be valid and we may
        not be able to obtain and enforce patents to protect our propriety
        rights from use by competitors" and "Business -- Patents and Proprietary
        Rights," insofar as such statements summarize legal matters, agreements,
        documents, or proceedings discussed therein, are accurate and fair
        summaries, in all material respects, of such legal matters, agreements,
        documents or proceedings.

                        (kk) Except as disclosed in the Registration Statement
        and the Prospectus, the Company (i) does not have any material lending
        or other relationship with any bank or lending affiliate of Citigroup
        Global Markets Inc. and (ii) does not intend to use any of the proceeds
        from the sale of the Securities hereunder to repay any outstanding debt
        owed to any affiliate of Citigroup Global Markets Inc.

                        (ll) Neither the Company nor any of its subsidiaries nor
        any of its or their properties or assets has any immunity from the
        jurisdiction of any court or from any legal process (whether through
        service or notice, attachment prior to judgment, attachment in aid of
        execution or otherwise) under the laws of Canada.

                        (mm) Neither the Company nor any of its subsidiaries is
        a party to any contract, agreement or understanding with any person that
        would give rise to a valid claim against the Company or the Underwriters
        for a brokerage commission, finder's fee or like payment in connection
        with the offering and sale of the Securities other than this Agreement.

                        (nn) Each of the transactions included in the
        Reorganization (as defined and described in the Prospectus) has been
        completed.

        Furthermore, the Company represents and warrants to Citigroup Global
Markets Inc. that (i) the Registration Statement, the Prospectus and any
preliminary prospectus comply, and any further amendments or supplements thereto
will comply, with any applicable laws or regulations of foreign jurisdictions in
which the Prospectus or any preliminary prospectus, as amended or supplemented,
if applicable, are distributed in connection with the Directed Share Program,
and that (ii) no authorization, approval, consent, license, order, registration
or qualification of or with any Governmental Authority or court, other than such
as have been obtained, is necessary under




                                      -12-
<PAGE>

the securities laws and regulations of foreign jurisdictions in which the
Directed Shares are offered outside the United States. The Company has not
offered, or caused the Underwriters to offer, Securities to any person pursuant
to the Directed Share Program with the specific intent to unlawfully influence
(x) a customer or supplier of the Company to alter the customer's or supplier's
level or type of business with the Company, or (y) a trade journalist or
publication to write or publish favorable information about the Company or its
products.

                Any certificate signed by any officer of the Company and
delivered to the Representatives or counsel for the Underwriters in connection
with the offering of the Securities shall be deemed a representation and
warranty by the Company, as to matters covered thereby, to each Underwriter.

                (ii) Each Selling Stockholder severally represents and warrants
to, and agrees with, each Underwriter that:

                        (a) Such Selling Stockholder is the record and
        beneficial owner of the Securities to be sold by it hereunder free and
        clear of all liens, encumbrances, equities and claims and has duly
        endorsed such Securities in blank, and, assuming that each Underwriter
        acquires its interest in the Securities it has purchased from such
        Selling Stockholder without notice of any adverse claim (within the
        meaning of Section 8-105 of the New York Uniform Commercial Code
        ("UCC")), each Underwriter that has purchased such Securities delivered
        on the Closing Date to The Depository Trust Company or other securities
        intermediary by making payment therefor as provided herein, and that has
        had such Securities credited to the securities account or accounts of
        such Underwriters maintained with The Depository Trust Company or such
        other securities intermediary will have acquired a security entitlement
        (within the meaning of Section 8-102(a)(17) of the UCC) to such
        Securities purchased by such Underwriter, and no action based on an
        adverse claim (within the meaning of Section 8-105 of the UCC) may be
        asserted against such Underwriter with respect to such Securities.

                        (b) Such Selling Stockholder has not taken, directly or
        indirectly, any action designed to or that would constitute or that
        might reasonably be expected to cause or result in, under the Exchange
        Act or otherwise, stabilization or manipulation of the price of any
        security of the Company to facilitate the sale or resale of the
        Securities.

                        (c) Certificates in negotiable form for such Selling
        Stockholder's Securities have been placed in custody, for delivery
        pursuant to the terms of this Agreement, under a Custody Agreement and
        Power of Attorney duly authorized (if applicable), executed and
        delivered by such Selling Stockholder, in the form heretofore furnished
        to you (the "Custody Agreement") with Mellon Investor Services LLC, as
        Custodian (the "Custodian"); the Securities represented by the
        certificates so held in custody for each Selling Stockholder are subject
        to the interests hereunder of the Underwriters; the arrangements for
        custody and delivery of such certificates, made by such Selling
        Stockholder hereunder and under the Custody Agreement, are not subject
        to termination by any acts of such Selling Stockholder, or by operation
        of law, whether by the death or incapacity of such Selling Stockholder
        or the occurrence of any other event; and if any such death, incapacity
        or any other such event shall occur before the delivery



                                      -13-
<PAGE>

        of such Securities hereunder, certificates for the Securities will be
        delivered by the Custodian in accordance with the terms and conditions
        of this Agreement and the Custody Agreement as if such death, incapacity
        or other event had not occurred, regardless of whether or not the
        Custodian shall have received notice of such death, incapacity or other
        event.

                        (d) No consent, approval, authorization or order of any
        court or Governmental Authority is required for the consummation by such
        Selling Stockholder of the transactions contemplated herein, except for
        the filing of the Canadian Supplemental PREP Prospectus with the
        Canadian Securities Commissions and except for such as may have been
        obtained under the Act and Canadian Securities Laws and such as may be
        required under the blue sky laws of any jurisdiction in connection with
        the purchase and distribution of the Securities by the Underwriters and
        such other approvals as have been obtained.

                        (e) Neither the sale of the Securities being sold by
        such Selling Stockholder nor the consummation of any other of the
        transactions herein contemplated by such Selling Stockholder or the
        fulfillment of the terms hereof by such Selling Stockholder will
        conflict with, result in a breach or violation of, or constitute a
        default under any law or the charter or by-laws or other governing
        document of such Selling Stockholder or the terms of any indenture or
        other agreement or instrument to which such Selling Stockholder or any
        of its subsidiaries is a party or bound, or any judgment, order or
        decree applicable to such Selling Stockholder or any of its subsidiaries
        of any court, regulatory body, administrative agency, Governmental
        Authority or arbitrator having jurisdiction over such Selling
        Stockholder or any of its subsidiaries.

                        (f) Each Selling Stockholder listed in Schedule II and
        identified as an Other Selling Stockholder (the "Other Selling
        Stockholders") has no reason to believe that the representations and
        warranties of the Company contained in this Section 1 are not true and
        correct, is familiar with the Registration Statement and the Prospectus
        and has no knowledge of any material fact, condition or information not
        disclosed in the Prospectus or any supplement thereto which has
        adversely affected or is reasonably likely to adversely affect the
        business of the Company and its subsidiaries, taken as a whole; and the
        sale of Securities by such Other Selling Stockholder pursuant hereto is
        not prompted by any information concerning the Company or any of its
        subsidiaries which is not set forth in the Prospectus and any supplement
        thereto.

                        (g) In respect of any statements in or omissions from
        the Registration Statement, the Prospectus or any supplements thereto
        made in reliance upon and in conformity with information furnished in
        writing to the Company by any Other Selling Stockholder specifically for
        use in connection with the preparation thereof, such Other Selling
        Stockholder hereby makes the same representations and warranties to each
        Underwriter as the Company makes to such Underwriter under paragraph
        (i)(c) of this Section.

                Any certificate signed by any Selling Stockholder or its
officers and delivered to the Representatives or counsel for the Underwriters in
connection with the offering of the




                                      -14-
<PAGE>

Securities shall be deemed a representation and warranty by such Selling
Stockholder, as to matters covered thereby, to each Underwriter.

        2. Purchase and Sale.

                        (a) Subject to the terms and conditions and in reliance
        upon the representations and warranties herein set forth, the Company
        and the Selling Stockholders agree, severally and not jointly, to sell
        to each Underwriter, and each Underwriter agrees, severally and not
        jointly, to purchase from the Company and the Selling Stockholders, at a
        purchase price of $[__________] per share, the amount of the
        Underwritten Securities set forth opposite such Underwriter's name in
        Schedule I hereto.

                        (b) Subject to the terms and conditions and in reliance
        upon the representations and warranties herein set forth, the Selling
        Stockholders named in Schedule II hereto hereby, severally and not
        jointly, grant an option to the several Underwriters to purchase,
        severally and not jointly, up to 1,260,000 Option Securities at the same
        purchase price per share as the Underwriters shall pay for the
        Underwritten Securities. Said option may be exercised only to cover
        over-allotments in the sale of the Underwritten Securities by the
        Underwriters. Said option may be exercised in whole or in part at any
        time on or before the 30th day after the date of the Prospectus upon
        written notice by the Representatives to such Selling Stockholders
        setting forth the number of shares of the Option Securities as to which
        the several Underwriters are exercising the option and the settlement
        date. The maximum number of Option Securities to be sold by the Selling
        Stockholders is 1,260,000. In the event that the Underwriters exercise
        less than their full over-allotment option, the number of Option
        Securities to be sold by each Selling Stockholder listed on Schedule II
        shall be, as nearly as practicable, in the same proportion as the
        maximum number of Option Securities to be sold by each Selling
        Stockholder and the number of Option Securities to be sold. The number
        of Option Securities to be purchased by each Underwriter shall be the
        same percentage of the total number of shares of the Option Securities
        to be purchased by the several Underwriters as such Underwriter is
        purchasing of the Underwritten Securities, subject to such adjustments
        as you in your absolute discretion shall make to eliminate any
        fractional shares.

        3. Delivery and Payment. Delivery of and payment for the Underwritten
Securities and the Option Securities (if the option provided for in Section 2(b)
hereof shall have been exercised on or before the third Business Day prior to
the Closing Date) shall be made at 10:00 a.m., New York City time, on December
[___], 2004, or at such time on such later date not more than three Business
Days after the foregoing date as the Representatives shall designate, which date
and time may be postponed by agreement among the Representatives, the Company
and the Selling Stockholders or as provided in Section 9 hereof (such date and
time of delivery and payment for the Securities being herein called the "Closing
Date"). Delivery of the Securities shall be made to the Representatives for the
respective accounts of the several Underwriters against payment by the several
Underwriters through the Representatives of the respective aggregate purchase
prices of the Securities being sold by the Company and each of the Selling
Stockholders to or upon the order of the Company and the Selling Stockholders by
wire transfer payable in same-day funds to the accounts specified by the Company
and the Selling



                                      -15-
<PAGE>

Stockholders. Delivery of the Underwritten Securities and the Option Securities
shall be made through the facilities of The Depository Trust Company unless the
Representatives shall otherwise instruct.

                Each Selling Stockholder will pay all applicable state transfer
taxes, if any, involved in the transfer to the several Underwriters of the
Securities to be purchased by them from such Selling Stockholder and the
respective Underwriters will pay any additional stock transfer taxes involved in
further transfers.

                If the option provided for in Section 2(b) hereof is exercised
after the third Business Day prior to the Closing Date, the Selling Stockholders
named in Schedule II hereto will deliver the Option Securities (at the expense
of the Company) to the Representatives, at 388 Greenwich Street, New York, New
York 10013, on the date specified by the Representatives (which shall be within
three Business Days after exercise of said option) for the respective accounts
of the several Underwriters, against payment by the several Underwriters through
the Representatives of the purchase price thereof to or upon the order of the
Selling Stockholders named in Schedule II by wire transfer payable in same-day
funds to the accounts specified by the Selling Stockholders named in Schedule II
hereto. If settlement for the Option Securities occurs after the Closing Date,
such Selling Stockholders will deliver to the Representatives on the settlement
date for the Option Securities, and the obligation of the Underwriters to
purchase the Option Securities shall be conditioned upon receipt of,
supplemental opinions, certificates and letters confirming as of such date the
opinions, certificates and letters delivered on the Closing Date pursuant to
Section 6 hereof.

        4. Offering by Underwriters. It is understood that the several
Underwriters propose to offer the Securities for sale to the public as set forth
in the Prospectus.

        5. Agreements.

                (i) The Company agrees with the several Underwriters that:

                        (a) Prior to the filing of the Registration Statement,
        the Canadian Final Prospectus, the Canadian Supplemental PREP Prospectus
        and any Supplementary Materials (as defined below), the Company shall
        allow the Underwriters to participate fully in the preparation of the
        Registration Statement, the Canadian Final Prospectus, the Canadian
        Supplemental PREP Prospectus and such Supplementary Materials,
        respectively, and shall allow the Underwriters to conduct all due
        diligence investigations which the Underwriters may reasonably require
        in order to fulfil their obligations as underwriters and in order to
        enable the Underwriters to responsibly execute the certificate required
        to be executed by the Underwriters in the Canadian Prospectus and any
        Supplementary Materials.

                        (b) The Company shall deliver to the Underwriters
        contemporaneously, as nearly as practicable, with the execution and
        delivery of this Agreement: (i) a copy of the Canadian Preliminary
        Prospectus and the Canadian Final Prospectus in each of the French and
        the English language signed and certified as required by the Canadian
        Securities Laws in each of the Canadian Qualifying Jurisdictions; (ii) a
        copy of all such documents and certificates that were filed with the


                                      -16-
<PAGE>

        Canadian Preliminary Prospectus and the Canadian Final Prospectus under
        Canadian Securities Laws; (iii) an opinion of its auditors, Ernst &
        Young LLP, addressed to the Underwriters and their counsel, in form and
        substance satisfactory to the Underwriters and their counsel, to the
        effect that the French language version of: (1) the consolidated
        financial statements of the Company, the financial statements of
        OccuLogix, L.P. and the pro forma consolidated financial statements of
        the Company forming part of the Canadian Preliminary Prospectus and the
        Canadian Final Prospectus, including the related notes thereto and the
        related auditors' reports thereon, (2) Management's Discussion and
        Analysis set out in the Canadian Preliminary Prospectus and the Canadian
        Final Prospectus, and (3) the "Summary Historical and Pro Forma
        Consolidated Financial Data", the "Unaudited Pro Forma Condensed
        Financial Data" and "Selected Consolidated Financial Data" set out in
        the Canadian Preliminary Prospectus and the Canadian Final Prospectus
        (all of the foregoing collectively known as the "Financial Information")
        is a complete and proper translation of the English language version
        thereof and such French language version is not susceptible to any
        materially different interpretation with respect to any material matter
        contained therein; (iv) an opinion of Desjardins Ducharme Stein Monast
        addressed to the Underwriters and their counsel in form and substance
        satisfactory to the Underwriters and their counsel, to the effect that,
        except for the Financial Information, the French language version of
        each of the Canadian Preliminary Prospectus and the Canadian Final
        Prospectus is a complete and proper translation of the English language
        version thereof and such French language version is not susceptible to
        any materially different interpretation with respect to any material
        matter contained therein; (v) evidence reasonably satisfactory to the
        Underwriters and their counsel that the Company has completed each of
        the transactions included in the Reorganization (as described in the
        Canadian Final Prospectus) as described in the Canadian Final
        Prospectus; and (vi) a letter from the TSX advising the Company that
        approval of the conditional listing of the Securities has been granted
        by the TSX, subject to the satisfaction of certain usual conditions set
        out therein. The deliveries set forth in (i) shall also constitute the
        Company's consent to the Underwriters' use of the Canadian Final
        Prospectus for the Distribution of the Securities in the Canadian
        Qualifying Jurisdictions in compliance with the provisions of this
        Agreement.

                        (c) The Company will use its best efforts to cause the
        Registration Statement, if not effective at the Execution Time, and any
        amendment thereof, to become effective.

                        (d) The Company will notify the Underwriters promptly,
        and confirm the notice in writing, when any amendment to the
        Registration Statement has been filed with the Commission or has become
        effective, and when the Canadian Supplemental PREP Prospectus containing
        the PREP information, or any amended Canadian Prospectus, U.S.
        Prospectus or any supplement thereto (collectively, "Supplementary
        Material") shall have been filed, in which case the Company shall
        deliver to the Underwriters all signed and certified copies of such
        Supplementary Material in the English and French languages along with
        all documents similar to those referred to in Section 5(i)(b)(i) (ii),
        (iii) and (iv) and such other documents as the Underwriters may
        reasonably request. Prior to the termination of the offering of the
        Securities and the Distribution, the Company will not file any amendment
        of the Registration Statement or




                                      -17-
<PAGE>

        supplement to the U.S. Prospectus or any Rule 462(b) Registration
        Statement or the U.S. Prospectus or any amendment to the Canadian
        Prospectus or the Canadian Supplemental PREP Prospectus unless the
        Company has furnished to the Underwriters a copy for their review prior
        to filing and will not file any such proposed amendment or supplement to
        which the Underwriters reasonably object. Subject to the foregoing
        sentence, if the Registration Statement has become or becomes effective
        pursuant to Rule 430A, or filing of the U.S. Prospectus is otherwise
        required under Rule 424(b), the Company will cause the U.S. Prospectus,
        properly completed, and any supplement thereto to be filed in a form
        approved by the Representatives with the Commission pursuant to the
        applicable paragraph of Rule 424(b) within the time period prescribed
        and will provide evidence reasonably satisfactory to the Representatives
        of such timely filing. The Company will promptly advise the
        Representatives in writing (1) when the Registration Statement, if not
        effective at the Execution Time, shall have become effective, (2) when
        the U.S. Prospectus, and any supplement thereto, shall have been filed
        (if required) with the Commission pursuant to Rule 424(b) or when any
        Rule 462(b) Registration Statement shall have been filed with the
        Commission, (3) when, prior to termination of the offering of the
        Securities and the Distribution, any amendment to the Registration
        Statement shall have been filed or become effective, (4) of any request
        by the Commission or its staff for any amendment of the Registration
        Statement, or any Rule 462(b) Registration Statement, or for any
        supplement to the U.S. Prospectus or for any additional information, or
        any request by any Canadian Securities Commission that the Company make
        any amendment to the Canadian Preliminary Prospectus, the Canadian Final
        Prospectus, the Canadian Supplemental PREP Prospectus, any Supplementary
        Material or that the Company provide any additional information in
        respect of the offering of the Securities, (5) of the issuance by the
        Commission of any stop order suspending the effectiveness of the
        Registration Statement or the institution or of the Company obtaining
        knowledge of the threatening of any proceeding for that purpose or the
        receipt by the Company of any written communication from any Canadian
        Securities Commission, the TSX or any other Governmental Authority
        relating to the Prospectus or the Distribution of the Securities and (6)
        of the receipt by the Company of any notification with respect to the
        suspension of the qualification of the Securities for sale in any
        jurisdiction or the institution or threatening of any proceeding for
        such purpose. The Company will use its best efforts to prevent the
        issuance of any such stop order or the suspension of any such
        qualification and, if issued, to obtain as soon as possible the
        withdrawal thereof.

                        (e) If, at any time when a prospectus relating to the
        Securities is required to be delivered under the Act, any event occurs
        as a result of which the Prospectus as then supplemented would include
        any untrue statement of a material fact or omit to state any material
        fact necessary to make the statements therein in the light of the
        circumstances under which they were made not misleading, or if it shall
        be necessary to amend the Registration Statement or supplement the
        Prospectus to comply with the Act or the rules thereunder, the Company
        promptly will (1) notify the Representatives of any such event, (2)
        prepare and file with the Commission, subject to the second sentence of
        paragraph (i)(d) of this Section 5, an amendment or supplement which
        will correct such statement or omission or effect such compliance and
        (3) supply any supplemented Prospectus to you in such quantities as you
        may reasonably request.



                                      -18-
<PAGE>

                        (f) Commencing on the date hereof and until the later of
        (1) the completion of the Distribution, or (2) the time at which the Act
        no longer requires a prospectus relating to the Securities to be
        delivered, the Company shall promptly notify the Underwriters in writing
        of:

                                (i) any change (actual, anticipated,
                        contemplated, proposed or threatened, financial or
                        otherwise) in the business, affairs, operations, assets,
                        properties, prospects, liabilities (contingent or
                        otherwise), capital, earnings or financial condition of
                        the Company or in any assumption or fact underlying any
                        forecast prepared by the Company and provided to the
                        Underwriters;

                                (ii) any change in any material fact (which
                        shall include the disclosure of any previously
                        undisclosed material fact) or any misstatement of any
                        material fact contained in the Prospectus or any
                        Supplementary Material;

                                (iii) the discovery of any new material fact
                        that would have been required to be disclosed in the
                        Prospectus or any Supplementary Material had it been
                        discovered prior to the date thereof; or

                                (iv) any change in Canadian Securities Laws or
                        the Act (in such case, the Company will notify the
                        Selling Stockholders as well);

                        which is, or may be, of such a nature as to render the
                Prospectus or any Supplementary Material misleading or untrue in
                whole or in part or would result in a misrepresentation (as such
                term is defined under Canadian Securities Laws) therein or would
                result in the Registration Statement, the Prospectus or any
                Supplementary Material not complying with any Canadian
                Securities Laws or the Act or which change, misstatement or new
                material fact would reasonably be expected to have a significant
                effect on the market price or value of the Securities.

                        (g) The Company will promptly (and in any event within
        any applicable time limitation) comply with all legal requirements under
        the Act, Canadian Securities Laws, and the rules and by-laws governing
        the TSX and Nasdaq National Market required as a result of an event
        described in Section 5(i)(f) in order to continue to qualify the
        Distribution of the Securities in each of the Canadian Qualifying
        Jurisdictions and the offering of the Securities in the United States
        pursuant to this Agreement, including the prospectus amendment
        provisions of the Canadian Securities Laws, and will prepare and file to
        the satisfaction of the Underwriters any Supplementary Material which,
        in the opinion of the Underwriters, may be necessary or advisable. In
        addition to the provisions of Section 5(i)(f) above, the Company will,
        in good faith, discuss with the Underwriters any change, event or fact
        contemplated in Section 5(i)(f) which is of such a nature that there may
        be reasonable doubt as to whether notice should be given to the
        Underwriters under Section 5(i)(f) and will consult with the
        Underwriters with respect to the form and content of any Supplementary
        Material proposed to be filed by the Company, it being understood and
        agreed that no such Supplementary Material will be




                                      -19-
<PAGE>

        filed with the Commission or any Canadian Securities Commission prior to
        the review and approval by the Underwriters and their counsel. The
        Company shall also cooperate in all respects with the Underwriters to
        allow and assist the Underwriters to participate in the preparation of
        any Supplementary Material and to conduct all due diligence
        investigations which the Underwriters deem appropriate in order to
        fulfill their obligations as underwriters and to enable the Underwriters
        to responsibly execute any certificate related to such Supplementary
        Material required to be executed by them.

                        (h) As soon as practicable, the Company will make
        generally available to its security holders and to the Representatives
        an earnings statement or statements of the Company and its subsidiaries
        which will satisfy the provisions of Section 11(a) of the Act and Rule
        158 under the Act.

                        (i) The Company will furnish to the Representatives and
        counsel for the Underwriters signed copies of the Registration Statement
        (including exhibits thereto) and to each other Underwriter a copy of the
        Registration Statement (without exhibits thereto) and, so long as
        delivery of a prospectus by an Underwriter or dealer may be required by
        the Act, as many copies of each Preliminary Prospectus and the
        Prospectus and any supplement thereto as the Representatives may
        reasonably request. The Company shall cause commercial copies of the
        Registration Statement and of the Canadian Prospectus in the English and
        French languages to be delivered to the Underwriters, without charge, in
        such numbers and in such places as the Underwriters may reasonably
        request. Such delivery shall be effected as soon as possible and, with
        respect to the Canadian Prospectus, not later than 12:00 p.m., New York
        time, on the first Business Day immediately following the date hereof.
        The Company shall similarly cause to be delivered commercial copies of
        any Supplementary Material required to be delivered, on request to the
        Underwriters or to any purchaser of Securities.

                        (j) The Company will arrange, if necessary, for the
        qualification of the Securities for sale under the laws of such
        jurisdictions as the Representatives may designate and will maintain
        such qualifications in effect so long as required for the distribution
        of the Securities; provided that in no event shall the Company be
        obligated to qualify to do business in any jurisdiction where it is not
        now so qualified or to take any action that would subject it to service
        of process in suits, other than those arising out of the offering or
        sale of the Securities or taxation, in any jurisdiction where it is not
        now so subject.

                        (k) The Company will not, without the prior written
        consent of Citigroup Global Markets Inc., offer, sell, contract to sell,
        pledge, or otherwise dispose of, (or enter into any transaction which is
        designed to, or might reasonably be expected to, result in the
        disposition (whether by actual disposition or effective economic
        disposition due to cash settlement or otherwise) by the Company or any
        affiliate of the Company or any person in privity with the Company or
        any affiliate of the Company) directly or indirectly, including the
        filing (or participation in the filing) of a registration statement with
        the Commission in respect of, or establish or increase a put equivalent
        position or liquidate or decrease a call equivalent position within the
        meaning of Section 16 of the Exchange Act, any other shares of Common
        Stock or any securities convertible



                                      -20-
<PAGE>

        into, or exercisable, or exchangeable for, shares of Common Stock; or
        publicly announce an intention to effect any such transaction, for a
        period of 180 days after the date of this Agreement, provided, however,
        that the Company may issue and sell Common Stock pursuant to any
        employee stock option plan (and may issue options thereunder), stock
        ownership plan or dividend reinvestment plan of the Company in effect at
        the Execution Time and the Company may issue Common Stock issuable upon
        the conversion of securities or the exercise of warrants outstanding at
        the Execution Time.

                        (l) The Company will comply with all applicable
        securities and other applicable laws, rules and regulations, including,
        without limitation, the Sarbanes Oxley Act, the Money Laundering Laws
        and the FCPA and use its best efforts to cause the Company's directors
        and officers, in their capacities as such, to comply with such laws,
        rules and regulations, including, without limitation, the provisions of
        the Sarbanes Oxley Act, the Money Laundering Laws and the FCPA.

                        (m) The Company will not take, directly or indirectly,
        any action designed to or that would constitute or that might reasonably
        be expected to cause or result in, under the Exchange Act or otherwise,
        stabilization or manipulation of the price of any security of the
        Company to facilitate the sale or resale of the Securities.

                        (n) The Company will not issue any press release or
        public announcement between the date hereof and the Closing Date without
        first consulting with the Representatives.

                        (o) The Company agrees to pay the costs and expenses
        relating to the following matters: (i) the preparation, printing or
        reproduction and filing with the Commission of the Registration
        Statement (including financial statements and exhibits thereto), each
        Preliminary Prospectus, the Prospectus, and each amendment or supplement
        to any of them; (ii) the preparation, printing or reproduction and
        filing with the Canadian Securities Commission of the Canadian
        Preliminary Prospectus, the Canadian Final Prospectus and the Canadian
        Supplemental PREP Prospectus, including any materials or certificates
        filed therewith, and each amendment or supplement to any of them; (iii)
        the printing (or reproduction) and delivery (including postage, air
        freight charges and charges for counting and packaging) of such copies
        of the Registration Statement, each Preliminary Prospectus, the
        Prospectus, the Canadian Preliminary Prospectus, the Canadian Prospectus
        and all amendments or supplements to any of them, as may, in each case,
        be reasonably requested for use in connection with the offering and sale
        of the Securities; (iv) the preparation, printing, authentication,
        issuance and delivery of certificates for the Securities, including any
        stamp or transfer taxes in connection with the original issuance and
        sale of the Securities; (v) the printing (or reproduction) and delivery
        of this Agreement, any blue sky memorandum and all other agreements or
        documents printed (or reproduced) and delivered in connection with the
        offering of the Securities; (vi) the registration of the Securities
        under the Exchange Act and the quotation of the Securities on the Nasdaq
        National Market and the listing of the Securities on the TSX; (vii) any
        registration or qualification of the Securities for offer and sale under
        the securities or blue sky laws of the several states (including filing
        fees and the reasonable fees and expenses of counsel for the
        Underwriters relating to such registration



                                      -21-
<PAGE>

        and qualification); (viii) any filings required to be made with the
        National Association of Securities Dealers, Inc. (including filing fees
        and the reasonable fees and expenses of counsel for the Underwriters
        relating to such filings); (ix) the transportation and other expenses
        incurred by or on behalf of Company representatives in connection with
        presentations to prospective purchasers of the Securities; (x) the fees
        and expenses of the Company's accountants and the fees and expenses of
        counsel (including local and special counsel) for the Company [and the
        Selling Stockholders]; and (xi) all other costs and expenses incident to
        the performance by the Company and the Selling Stockholders of their
        obligations hereunder.

                        (p) The Company will use the net proceeds from the sale
        of the Securities in the manner described in the Prospectus.

                        (q) The Company agrees to pay (1) all fees and
        disbursements of counsel incurred by the Underwriters in connection with
        the Directed Share Program, (2) all costs and expenses incurred by the
        Underwriters in connection with the printing (or reproduction) and
        delivery (including postage, air freight charges and charges for
        counting and packaging) of copies of the Directed Share Program material
        and (3) all stamp duties, similar taxes or duties or other taxes, if
        any, incurred by the Underwriters in connection with the Directed Share
        Program.

                Furthermore, the Company covenants with Citigroup Global Markets
        Inc. that the Company will comply with all applicable securities and
        other applicable laws, rules and regulations in each foreign
        jurisdiction in which the Directed Shares are offered in connection with
        the Directed Share Program.

                (ii) Each Selling Stockholder agrees with the several
        Underwriters that:

                        (a) Such Selling Stockholder will not, without the prior
        written consent of Citigroup Global Markets Inc., offer, sell, contract
        to sell, pledge or otherwise dispose of, (or enter into any transaction
        which is designed to, or might reasonably be expected to, result in the
        disposition (whether by actual disposition or effective economic
        disposition due to cash settlement or otherwise) by the Selling
        Stockholder or any affiliate of the Selling Stockholder or any person in
        privity with the Selling Stockholder or any affiliate of the Selling
        Stockholder) directly or indirectly, or file (or participate in the
        filing of) a registration statement with the Commission in respect of,
        or establish or increase a put equivalent position or liquidate or
        decrease a call equivalent position within the meaning of Section 16 of
        the Exchange Act with respect to, any shares of capital stock of the
        Company or any securities convertible into or exercisable or
        exchangeable for such capital stock, or publicly announce an intention
        to effect any such transaction, for a period of 180 days after the date
        of this Agreement, other than shares of Common Stock disposed of as bona
        fide gifts approved by Citigroup Global Markets Inc.

                        (b) Such Selling Stockholder will not take, directly or
        indirectly, any action designed to or that would constitute or that
        might reasonably be expected to cause or result in, under the Exchange
        Act or otherwise, stabilization or manipulation of the price of any
        security of the Company to facilitate the sale or resale of the
        Securities.



                                      -22-
<PAGE>

                        (c) Such Selling Stockholder will advise you promptly,
        and if requested by you, will confirm such advice in writing, so long as
        delivery of a prospectus relating to the Securities by an underwriter or
        dealer may be required under the Act, of (i) any material change in the
        Company's condition (financial or otherwise), prospects, earnings,
        business or properties, (ii) any change in information in the
        Registration Statement or the Prospectus relating to such Selling
        Stockholder or (iii) any new material information relating to the
        Company or relating to any matter stated in the Prospectus which comes
        to the attention of such Selling Stockholder.

                        (d) Commencing on the date hereof and until the later of
        (1) the completion of the Distribution, or (2) the time at which the Act
        no longer requires a prospectus relating to the Securities to be
        delivered, such Selling Stockholder will advise the Underwriters
        promptly, and if requested by the Representatives, will confirm such
        advice in writing, of:

                                (i) any change (actual, anticipated,
                        contemplated, proposed or threatened, financial or
                        otherwise) in the business, affairs, operations, assets,
                        properties, prospects, liabilities (contingent or
                        otherwise), capital, earnings or financial condition of
                        the Company or in any assumption or fact underlying any
                        forecast prepared by the Company and provided to the
                        Underwriters;

                                (ii) any change in any material fact (which
                        shall include the disclosure of any previously
                        undisclosed material fact) or any misstatement of any
                        material fact contained in the Prospectus or any
                        Supplementary Material;

                                (iii) the discovery of any new material fact
                        that would have been required to be disclosed in the
                        Prospectus or any Supplementary Material had it been
                        discovered prior to the date thereof; or

                                (iv) any change in Canadian Securities Laws or
                        the Act which is not otherwise brought to the attention
                        of the Underwriters by the Company in writing;

                        which comes to the attention of the Selling Stockholder
                        and which is, or may be, of such a nature as to render
                        the Prospectus or any Supplementary Material misleading
                        or untrue in whole or in part or would result in a
                        misrepresentation therein or would result in the
                        Prospectus or any Supplementary Material not complying
                        with any Canadian Securities Laws or the Act or which
                        change, misstatement or new material fact would
                        reasonably be expected to have a significant effect on
                        the market price or value of the Securities.

                        (e) Such Selling Stockholder will not issue any press
        release or public announcement between the date hereof and the Closing
        Date relating in any way to the offering and the sale of the Securities
        without first consulting with the Representatives.



                                      -23-
<PAGE>

                        (f) Such Selling Stockholder will comply with the
        agreement contained in Section 5(i)(o).

        6. Conditions to the Obligations of the Underwriters. The obligations of
the Underwriters to purchase the Underwritten Securities and the Option
Securities, as the case may be, shall be subject to the accuracy of the
representations and warranties on the part of the Company and the Selling
Stockholders contained herein as of the Execution Time, the Closing Date and any
settlement date pursuant to Section 3 hereof, to the accuracy of the statements
of the Company and the Selling Stockholders made in any certificates pursuant to
the provisions hereof, to the performance by the Company and the Selling
Stockholders of their respective obligations hereunder and to the following
additional conditions:

                        (a) If the Registration Statement has not become
        effective prior to the Execution Time, unless the Representatives agree
        in writing to a later time, the Registration Statement will become
        effective not later than (i) 6:00 p.m. New York City time on the date of
        determination of the public offering price, if such determination
        occurred at or prior to 3:00 p.m. New York City time on such date or
        (ii) 9:30 a.m. on the Business Day following the day on which the public
        offering price was determined, if such determination occurred after 3:00
        p.m. New York City time on such date; if filing of the U.S. Prospectus,
        or any supplement thereto, is required pursuant to Rule 424(b), the U.S.
        Prospectus, and any such supplement, will be filed in the manner and
        within the time period required by Rule 424(b).

                        (b) The Canadian Supplemental PREP Prospectus shall have
        been filed with the Canadian Securities Commissions in accordance with
        the PREP Procedures.

                        (c) No order having the effect of ceasing or suspending
        the Distribution or offering of the Securities shall have been issued or
        proceedings therefor initiated or threatened by any securities
        commission, securities regulatory authority, stock exchange, the Nasdaq
        National Market or the TSX, and no stop order suspending the
        effectiveness of the Registration Statement shall have been issued and
        no proceedings for that purpose shall have been instituted or
        threatened, and any request on the part of the Commission or any
        Canadian Securities Commission for additional information shall have
        been complied with to the reasonable satisfaction of the Underwriters.

                        (d) The Company shall have requested and caused Torys
        LLP, counsel for the Company, to have furnished to the Underwriters
        their opinion, dated the Closing Date and addressed to the Underwriters
        and their counsel, to the effect that:

                                (i) each of the Company and each subsidiary
                        listed on Annex A hereto (individually a "Subsidiary"
                        and collectively the "Subsidiaries") that is organized
                        in Delaware or Ontario has been duly organized and is
                        validly existing as a corporation or partnership (as
                        applicable) in good standing under the laws of the
                        jurisdiction in which it is chartered or organized, with
                        full corporate or partnership (as applicable) power and
                        authority to own or lease, as the case may be, and to
                        operate its properties



                                      -24-
<PAGE>

                        and conduct its business as described in the Prospectus,
                        and the Company and each Subsidiary organized in
                        Delaware is duly qualified to do business as a foreign
                        corporation and is in good standing under the laws of
                        each jurisdiction set forth on Schedule A to such
                        counsel's opinion;

                                (ii) all the outstanding shares of capital stock
                        or other equity interests of each Subsidiary have been
                        duly and validly authorized and issued and are fully
                        paid and nonassessable, and, except as otherwise set
                        forth in the Prospectus, all outstanding shares of
                        capital stock or other equity interests of the
                        Subsidiaries are owned by the Company either directly or
                        through wholly owned subsidiaries free and clear of any
                        perfected security interest and, to the knowledge of
                        such counsel, after due inquiry, any other security
                        interest, claim, lien or encumbrance;

                                (iii) the Company's authorized equity
                        capitalization is as set forth in the Prospectus; the
                        capital stock of the Company conforms in all material
                        respects to the description thereof contained in the
                        Prospectus; the outstanding shares of Common Stock
                        (including the Securities being sold hereunder by the
                        Selling Stockholders) have been duly and validly
                        authorized and issued and are fully paid and
                        nonassessable; the Securities being sold hereunder by
                        the Company have been duly and validly authorized, and,
                        when issued and delivered to and paid for by the
                        Underwriters pursuant to this Agreement, will be fully
                        paid and nonassessable; the Securities have been
                        approved for quotation on the Nasdaq National Market,
                        subject to official notice of issuance and evidence of
                        satisfactory distribution; the Securities have been
                        conditionally approved for listing on the TSX, subject
                        only to compliance with minimum distribution
                        requirements and the Company providing to the TSX
                        certain required routine documentation; the certificates
                        for the Securities have been duly approved and adopted
                        by the Company and are in valid and sufficient form and
                        comply with the requirements of the Nasdaq National
                        Market and the TSX; the holders of outstanding shares of
                        capital stock of the Company are not entitled, pursuant
                        to the Company's Certificate of Incorporation, the DGCL
                        or any contract or agreement to which the Company is a
                        party and known to such counsel, to preemptive or other
                        rights to subscribe for the Securities; and, except as
                        set forth in the Prospectus, no options, warrants or
                        other rights to purchase, agreements or other
                        obligations to issue, or rights to convert any
                        obligations into or exchange any securities for, in each
                        case to which the Company is a party, shares of capital
                        stock of or ownership interests in the Company are
                        outstanding;

                                (iv) to the knowledge of such counsel, there is
                        no pending or threatened action, suit or proceeding by
                        or before any court or Governmental Authority or any
                        arbitrator involving the Company or any of its
                        subsidiaries or its or their property of a character
                        required to be disclosed in the Registration Statement
                        or the Prospectus which is not



                                      -25-
<PAGE>

                        adequately disclosed in the Prospectus, and there is no
                        franchise, contract or other document of a character
                        required to be described in the Registration Statement
                        or Prospectus, or to be filed as an exhibit thereto,
                        which is not described or filed as required; and the
                        statements in the Prospectus under the headings "Risk
                        Factors - We currently depend on single sources for key
                        components of the RHEO System. The loss of any of these
                        sources could delay our clinical trials or prevent or
                        delay commercialization of the RHEO System," "Risk
                        Factors - Our supply agreement with Asahi Medical
                        requires us to transfer the FDA approval of the RHEO
                        System to it upon receipt which will limit our control
                        of the FDA approval, "Risk Factors - Future sales of our
                        common stock could reduce our stock price," "Risk
                        Factors - We have entered into a number of related party
                        transactions with suppliers, creditors, stockholders and
                        other parties, each of which may have interests which
                        conflict with those of our public stockholders,"
                        "Business - Clinical Studies - MIRA-1," "Business -
                        Supplier Relationships," "Reorganization," "Management,"
                        "Certain Relationships and Related Party Transactions,"
                        "Description of Capital Stock" and "Shares Eligible for
                        Future Sale," insofar as such statements summarize legal
                        matters, agreements, documents or legal proceedings
                        discussed therein, are accurate and fair summaries, in
                        all material respects, of such legal matters,
                        agreements, documents or legal proceedings;

                                (v) the Registration Statement has become
                        effective under the Act; any required filing of the U.S.
                        Prospectus, and any supplements thereto, pursuant to
                        Rule 424(b) has been made in the manner and within the
                        time period required by Rule 424(b); to the knowledge of
                        such counsel, no stop order suspending the effectiveness
                        of the Registration Statement has been issued, no
                        proceedings for that purpose have been instituted or
                        threatened and the Registration Statement and the U.S.
                        Prospectus (other than the financial statements and
                        other financial and statistical information contained
                        therein, as to which such counsel need express no
                        opinion) comply as to form in all material respects with
                        the applicable requirements of the Act and the rules
                        thereunder; and such counsel has no reason to believe
                        that on the Effective Date or the date the Registration
                        Statement was last deemed amended the Registration
                        Statement contained any untrue statement of a material
                        fact or omitted to state any material fact required to
                        be stated therein or necessary to make the statements
                        therein not misleading or that the Prospectus as of its
                        date and on the Closing Date included or includes any
                        untrue statement of a material fact or omitted or omits
                        to state a material fact necessary to make the
                        statements therein, in the light of the circumstances
                        under which they were made, not misleading (in each
                        case, other than the financial statements and other
                        financial and statistical information contained therein,
                        as to which such counsel need express no opinion);

                                (vi) all necessary corporate action has been
                        taken by the Company to authorize the execution and
                        delivery of each of the Canadian




                                      -26-
<PAGE>

                        Preliminary Prospectus and the Canadian Final Prospectus
                        and the filing thereof and the Canadian Supplemental
                        PREP Prospectus under Canadian Securities Laws in each
                        of the Canadian Qualifying Jurisdictions;

                                (vii) all documents have been filed and all
                        requisite proceedings have been taken and all approvals,
                        permits, consents and authorizations of appropriate
                        regulatory authorities under Canadian Securities Laws
                        have been obtained to qualify the Distribution of the
                        Over-Allotment Option and the Securities in each of the
                        Canadian Qualifying Jurisdictions through investment
                        dealers or brokers duly registered under the Canadian
                        Securities Laws of each such Canadian Qualifying
                        Jurisdiction who have complied with the relevant
                        provisions of the Canadian Securities Laws of such
                        Canadian Qualifying Jurisdiction;

                                (viii) this Agreement has been duly authorized,
                        executed and delivered by the Company;

                                (ix) the Company is not and, after giving effect
                        to the offering and sale of the Securities and the
                        application of the proceeds thereof as described in the
                        Prospectus, will not be, an "investment company" as
                        defined in the Investment Company Act of 1940, as
                        amended;

                                (x) no consent, approval, authorization, filing
                        with or order of any U.S. Federal, New York or Delaware
                        State or Canadian court or Governmental Authority is
                        required in connection with the transactions
                        contemplated herein, except such as have been obtained
                        under the Act and the Canadian Securities Laws and such
                        as may be required under the blue sky laws of any
                        jurisdiction in connection with the purchase and
                        distribution of the Securities by the Underwriters in
                        the manner contemplated in this Agreement and in the
                        Prospectus and such other approvals (specified in such
                        opinion) as have been obtained;

                                (xi) neither the issue and sale of the
                        Securities, nor the consummation of any other of the
                        transactions herein contemplated nor the fulfillment of
                        the terms hereof will conflict with, result in a breach
                        or violation of, or imposition of any lien, charge or
                        encumbrance upon any property or assets of the Company
                        or its subsidiaries pursuant to, (i) the charter or
                        by-laws of the Company or its subsidiaries, (ii) the
                        terms of any indenture, contract, lease, mortgage, deed
                        of trust, note agreement, loan agreement or other
                        agreement, obligation, condition, covenant or instrument
                        known to such counsel to which the Company or its
                        subsidiaries is a party or bound or to which its or
                        their property is subject; or (iii) any statute, law,
                        rule, regulation, judgment, order or decree known to
                        such Counsel to be applicable to the Company or its
                        subsidiaries of any U.S. Federal, New York or Delaware
                        State or Canadian court, regulatory body, administrative
                        agency, Governmental Authority, arbitrator or other


                                      -27-
<PAGE>

                        authority having jurisdiction over the Company or its
                        subsidiaries or any of its or their properties;

                                (xii) the Securities are qualified investments
                        under the Income Tax Act (Canada) and the regulations
                        thereunder (the "Tax Act") for trusts governed by
                        registered retirement savings plans, registered
                        retirement income funds, deferred profit sharing plans
                        and registered education savings plans (collectively,
                        "Plans") and will constitute foreign property for the
                        purposes of the tax imposed under Part XI of the Tax Act
                        on Plans (other than registered education savings
                        plans), registered pension plans and other tax exempt
                        entities;

                                (xiii) no holders of securities of the Company
                        have rights to the registration of such securities under
                        the Registration Statement, except for such rights as
                        have been satisfied or waived;

                                (xiv) each of the transactions included in the
                        Reorganization (as defined in the Prospectus) has been
                        completed as described in the Prospectus; and

                                (xv) such other matters as the Underwriters may
                        reasonably request.

In rendering such opinion, such counsel may rely (A) as to matters involving the
application of laws of any jurisdiction other than the State of New York or the
Province of Ontario and the laws of Canada applicable therein, and as to matters
involving the application of laws other than the Delaware General Corporation
Law (the "DGCL") or the Federal laws of the United States, in each case, to the
extent they deem proper and specified in such opinion, upon the opinion of other
counsel of good standing whom they believe to be reliable and who are reasonably
satisfactory to counsel for the Underwriters, including the opinion of Holland &
Knight LLP, Florida counsel to the Company, and (B) as to matters of fact, to
the extent they deem proper, on certificates of responsible officers of the
Company and public officials. References to the Prospectus in this paragraph (d)
shall also include any supplements thereto at the Closing Date.

                        (e) The Company shall have requested and caused Morgan,
        Lewis & Bockius LLP, intellectual property counsel for the Company, to
        have furnished to the Underwriters their opinion, dated the Closing Date
        and addressed to the Underwriters and their counsel, to the effect that:

                                (i) the Company is the record owner of U.S.
                        patent number 6,551,266 (the "Owned Patent") and such
                        patent is valid and subsisting;

                                (ii) the Company is the exclusive licensee of
                        U.S. patent number 6,245,038 (the "Licensed Patent" and
                        together with the Owned Patent, the "Patents") and, upon
                        reexamination of such patent, such counsel believes that
                        it is reasonably likely that a more detailed claim set
                        will be issued and valid;



                                      -28-
<PAGE>

                                (iii) the Patents are entitled to a statutory
                        presumption of validity and of ownership by the
                        respective assignees and, to such counsel's knowledge,
                        there are no liens which have been filed against any of
                        the Patents;


                                (iv) such counsel has conducted prior art
                        searches for each of the Patents;


                                (v) the Company's Owned Patent application filed
                        in the U.S. (the "Owned Patent Application") was
                        properly prepared and filed on behalf of the Company,
                        disclosed patentable subject matter and, to the best of
                        such counsel's knowledge, the Company complied with all
                        applicable examination requirements of duty of candor
                        and disclosure with respect to the Owned Patent
                        Application;


                                (vi) the inventions described in the Owned
                        Patent Application were assigned to the Company and, to
                        the best of such counsel's knowledge, no other entity or
                        individual has any right or claim in any of such
                        inventions or the Owned Patent;


                                (vii) the Company's pending patent application
                        filed in the U.S. (the "Pending Application") has been
                        properly prepared and filed on behalf of the Company,
                        discloses patentable subject matter and is being
                        diligently pursued by the Company and, to the best of
                        such counsel's knowledge, the Company has complied with
                        all applicable examination requirements of duty of
                        candor and disclosure with respect to the Pending
                        Application;


                                (viii) the Company is the record owner of the
                        Pending Application, the inventions described in the
                        Pending Application are assigned to the Company and, to
                        the best of such counsel's knowledge, no other entity or
                        individual has any right or claim in any of the
                        inventions, Pending Application or any patent to be
                        issued therefrom;


                                (ix) the statements contained in the
                        Registration Statement and Prospectus including, but not
                        limited to, the statements under the captions "Risk
                        Factors - If we are unable to protect our intellectual
                        property rights, our competitive position could be
                        harmed," "Risk Factors - Third party claims of
                        infringement or other claims against us could require us
                        to redesign our products, seek licenses, or engage in
                        future costly intellectual property litigation, which
                        could impact our future business and financial
                        performance" and "Business - Intellectual Property"
                        (collectively, the "Intellectual Property Portion") are
                        accurate descriptions of the Patents and the Pending
                        Application and fairly summarizes the legal matters,
                        documents and proceedings relating thereto of which such
                        counsel is aware;



                                      -29-
<PAGE>

                                (x) except as disclosed in the Prospectus, such
                        counsel is not aware or has not been put on notice of
                        any valid patent that is or would be infringed by the
                        activities of the Company in the manufacture, use or
                        sale of any presently proposed product, as described in
                        the Prospectus;


                                (xi) except as disclosed in the Prospectus, such
                        counsel is not aware of any pending or threatened
                        judicial or governmental proceedings relating to patents
                        or proprietary information to which the Company is a
                        party or of which any property of the Company is
                        subject, including any interference, reexamination,
                        reissue or declaratory action proceeding, and such
                        counsel is not aware of any pending or threatened
                        action, suit or claim by others that the Company is
                        infringing or otherwise violating any patent rights of
                        others, nor is such counsel aware of any rights of third
                        parties to any of the Company's inventions described in
                        the Pending Application or the Patents which could
                        reasonably be expected to materially affect the ability
                        of the Company to conduct its business as described in
                        the Registration Statement and Prospectus;


                                (xii) to such counsel's knowledge, no third
                        party is infringing any of the Patents; and


                                (xiii) such counsel has no reason to believe
                        that the information contained in the Intellectual
                        Property Portion of the Registration Statement, as of
                        the Effective Date, and the Prospectus, as of its date,
                        contained any untrue statement of a material fact or
                        omitted to state any material fact necessary to make the
                        statements therein, in the light of the circumstances
                        under which they were made, not misleading.


In rendering such opinion, such counsel may rely (A) as to matters involving the
application of laws other than the Federal laws of the United States, to the
extent they deem proper and specified in such opinion, upon the opinion of other
counsel of good standing whom they believe to be reliable and who are
satisfactory to counsel for the Underwriters and (B) as to matters of fact, to
the extent they deem proper, on certificates of responsible officers of the
Company and public officials.

                        (f) The Company shall have requested and caused Buc &
        Beardsley, U.S. Food and Drug Administration ("FDA") counsel for the
        Company, to have furnished to the Underwriters their opinion, dated the
        Closing Date and addressed to the Underwriters and their counsel, to the
        effect that:


                                (i) the statements contained in the Registration
                        Statement and Prospectus under the captions "Risk
                        Factors - Even if we complete MIRA-1, we may not receive
                        FDA approval to market the RHEO System in the United
                        States," "Risk Factors - If we or our suppliers fail to
                        comply with the extensive regulatory requirements to
                        which we and the RHEO System are subject, the RHEO
                        System could be subject to restrictions or withdrawals
                        from the market and we could be subject to penalties"
                        and



                                      -30-
<PAGE>

                        "Business - Government Regulation," (collectively, the
                        "FDA Portion") insofar as such statements purport to
                        summarize provisions of the Federal Food, Drug, and
                        Cosmetic Act (the "FFDCA") and implementing regulations
                        are correct in all material respects of the provisions
                        of the FFDCA and the regulations thereunder purported to
                        be summarized under such captions in the Registration
                        Statement and the Prospectus; and


                                (ii) although such counsel has made no
                        independent inquiry, nothing has come to such counsel's
                        attention that leads them to believe that the statements
                        contained in the FDA Portion of the Registration
                        Statement, as of the Effective Date, and in the FDA
                        Portion of the Prospectus, as of its date, contained any
                        untrue statement of a material fact related to FDA
                        regulatory matters or omitted to state any material fact
                        related to FDA regulatory matters necessary to make the
                        statements therein, in the light of the circumstances
                        under which they were made, not misleading.


In rendering such opinion, such counsel may rely as to matters of fact, to the
extent they deem proper, on certificates of responsible officers of the Company
and public officials.


                        (g) The Major Selling Stockholders shall have requested
        and caused Thompson Coburn LLP, special counsel for the Major Selling
        Stockholders, to have furnished to the Underwriters their opinion dated
        the Closing Date and addressed to the Underwriters and their counsel, to
        the effect that:

                                (i) this Agreement and the Custody Agreement and
                        Power of Attorney have been duly authorized, executed
                        and delivered by the Major Selling Stockholders, the
                        Custody Agreement is valid and binding on the Major
                        Selling Stockholders and each Major Selling Stockholder
                        has full legal right and authority to sell, transfer and
                        deliver in the manner provided in this Agreement and the
                        Custody Agreement the Securities being sold by such
                        Selling Stockholder hereunder;

                                (ii) assuming that each Underwriter acquires its
                        interest in the Securities it has purchased from such
                        Selling Stockholder without notice of any adverse claim
                        (within the meaning of Section 8-105 of the UCC), each
                        Underwriter that has purchased such Securities delivered
                        on the Closing Date to The Depository Trust Company or
                        other securities intermediary by making payment therefor
                        as provided herein, and that has had such Securities
                        credited to the securities account or accounts of such
                        Underwriters maintained with The Depository Trust
                        Company or such other securities intermediary will have
                        acquired a security entitlement (within the meaning of
                        Section 8-102(a)(17) of the UCC) to such Securities
                        purchased by such Underwriter, and no action based on an
                        adverse claim (within the meaning of Section 8-105 of
                        the UCC) may be asserted against such Underwriter with
                        respect to such Securities;



                                      -31-
<PAGE>


                                (iii) to such counsel's knowledge, no consent,
                        approval, authorization or order of any court or
                        Governmental Authority is required for the consummation
                        by any Selling Stockholder of the transactions
                        contemplated herein, except such as may have been
                        obtained under the Act, Ontario securities laws and such
                        as may be required under the blue sky laws of any
                        jurisdiction in connection with the purchase of the
                        Securities by the Underwriters and such other approvals
                        (specified in such opinion) as have been obtained; and



                                (iv) neither the sale of the Securities being
                        sold by any Selling Stockholder nor the consummation of
                        any other of the transactions herein contemplated by any
                        Selling Stockholder or the fulfillment of the terms
                        hereof by any Selling Stockholder will conflict with,
                        result in a breach or violation of, or constitute a
                        default under any law or, with respect to TLC Vision
                        Corporation ("TLC") only, the terms of any indenture or
                        other agreement or instrument filed as an exhibit to
                        TLC's 2003 Form 10-K, or any judgment, order or decree
                        known to such counsel to be applicable to any Selling
                        Stockholder or any of its subsidiaries of any court,
                        regulatory body, administrative agency, Governmental
                        Authority or arbitrator having jurisdiction over any
                        Selling Stockholder or any of its subsidiaries.



In rendering such opinion, such counsel may rely (A) as to matters involving the
application of laws of any jurisdiction other than the State of New York, and as
to matters involving the application of laws other than the Delaware General
Corporation Law (the "DGCL") or the Federal laws of the United States, in each
case, to the extent they deem proper and specified in such opinion, upon the
opinion of other counsel of good standing whom they believe to be reliable and
who are satisfactory to counsel for the Underwriters, including the opinion of
Stewart McKelvey Stirling Scales, Canadian counsel to TLC, and (B) as to matters
of fact, to the extent they deem proper, on certificates of the Major Selling
Stockholders and their respective responsible officers and public officials.



                        (h) TLC shall have requested and caused Stewart McKelvey
        Stirling Scales, Canadian counsel for TLC, to have furnished to the
        Representatives their opinion, dated the Closing Date and addressed to
        the Representatives, to the effect that:


                                (i) TLC is a corporation validly existing under
                        the laws of the Province of New Brunswick;

                                (ii) this Agreement and the Custody Agreement
                        and Power of Attorney have been duly authorized by all
                        necessary corporate action on the part of TLC and has
                        been duly executed and delivered by TLC;

                                (iii) TLC has the corporate power and capacity
                        to sell, transfer and deliver, in the manner provided in
                        this Agreement and the Custody Agreement, the Securities
                        being sold by TLC hereunder;

                                (iv) no consent, approval, authorization or
                        order of any court or governmental agency or body of the
                        Province of New Brunswick or of



                                      -32-
<PAGE>

                        Canada is required in connection with the consummation
                        by TLC of the transactions contemplated herein;

                                (v) neither the sale of the Securities being
                        sold by TLC or the performance by TLC of its obligations
                        under this Agreement or the fulfillment of the terms
                        hereof by TLC will conflict with, result in a breach or
                        violation of, or constitute default under (i) any law of
                        the Province of New Brunswick or any federal law of
                        Canada, (ii) the articles or by-laws of TLC or (iii) the
                        terms of any indenture or other agreement or instrument
                        known to such counsel and to which TLC or any of its
                        subsidiaries is a party or bound, or any judgment, order
                        or decree known to such counsel to be applicable to TLC
                        or any of its subsidiaries of any New Brunswick or
                        Canadian court, regulatory body, administrative agency,
                        governmental body or arbitrator having jurisdiction over
                        TLC or any of its subsidiaries; and

                                (vi) all documents have been filed and all
                        requisite proceedings have been taken and all approvals,
                        permits, consents and authorizations of the securities
                        regulatory authorities of each of the Atlantic Provinces
                        (as defined is such opinion) have been obtained to
                        qualify the distribution of the Securities in each of
                        the Atlantic Provinces through investment dealers or
                        brokers duly registered under the applicable Securities
                        Laws (as defined is such opinion) who have complied with
                        the relevant provisions of such applicable Securities
                        Laws.

In rendering such opinion, such counsel may rely (A) as to matters involving the
application of laws of any jurisdiction other than Canada or the Province of New
Brunswick, to the extent they deem proper and specified in such opinion, upon
the opinion of other counsel of good standing whom they believe to be reliable
and who are satisfactory to counsel for the Underwriters and (B) as to matters
of fact, to the extent they deem proper, on certificates of responsible officers
of the Company and public officials.


                        (i) The Representatives shall have received from Piper
        Rudnick LLP, U.S. counsel for the Underwriters, and Stikeman Elliot LLP,
        Canadian counsel for the Underwriters, such opinion or opinions, dated
        the Closing Date and addressed to the Representatives, with respect to
        the issuance and sale of the Securities, the Registration Statement, the
        U.S. Prospectus (together with any supplement thereto), the Canadian
        Prospectus and other related matters as the Representatives may
        reasonably require, and the Company and each Selling Stockholder shall
        have furnished to such counsel such documents as they reasonably request
        for the purpose of enabling them to pass upon such matters.



                        (j) The Company shall have furnished to the
        Representatives certificates dated the Closing Date, signed by
        appropriate officers of the Company, addressed to the Underwriters and
        their counsel, with respect to the charter and by-laws of the Company,
        all resolutions of the board of directors of the Company and other
        corporate action relating to this Agreement and to the authorization,
        issue and sale of the




                                      -33-
<PAGE>

        Securities, the incumbency and specimen signatures of signing officers
        and with respect to such other matters as the Underwriters may
        reasonably request;

                        (k) The Company shall have furnished to the
        Representatives a certificate of the Company, signed by the Chief
        Executive Officer and Chief Financial Officer of the Company in their
        capacities as such and not individually, dated the Closing Date, to the
        effect that the signers of such certificate have carefully examined the
        Registration Statement, the U.S. Prospectus, any supplements to the U.S.
        Prospectus, the Canadian Prospectus, any Supplementary Material and this
        Agreement and that:

                                (i) the representations and warranties of the
                        Company in this Agreement are true and correct on and as
                        of the Closing Date with the same effect as if made on
                        the Closing Date and the Company has complied with all
                        the agreements and satisfied all the conditions on its
                        part to be performed or satisfied at or prior to the
                        Closing Date;

                                (ii) no stop order suspending the effectiveness
                        of the Registration Statement has been issued and no
                        proceedings for that purpose have been instituted or, to
                        the Company's knowledge, threatened;

                                (iii) no order, ruling or determination having
                        the effect of suspending the sale or ceasing the trading
                        of the Securities or any other securities of the Company
                        has been issued or made by any Governmental Authority
                        and is continuing in effect and no proceedings for that
                        purpose have been instituted or are pending or, to the
                        knowledge of the Company, contemplated or threatened by
                        any Governmental Authority;

                                (iv) since December 31, 2003, there has been no
                        material adverse effect on the condition (financial or
                        otherwise), prospects, earnings, business or properties
                        of the Company and its subsidiaries taken as a whole,
                        whether or not arising from transactions in the ordinary
                        course of business, except as set forth in or
                        contemplated in the Prospectus (exclusive of any
                        supplement thereto); and

                                (v) such other matters as the Underwriters may
                        reasonably request.

                        (l) Each Selling Stockholder shall have furnished to the
        Representatives a certificate, signed by the Attorneys-in-Fact appointed
        in the Custody Agreement, dated the Closing Date, to the effect that
        such Selling Stockholder has carefully examined the Registration
        Statement, the U.S. Prospectus, any supplement to the U.S. Prospectus,
        the Canadian Prospectus and any Supplementary Material and this
        Agreement and that the representations and warranties of such Selling
        Stockholder in this Agreement are true and correct in all material
        respects on and as of the Closing Date to the same effect as if made on
        the Closing Date and that such Selling Stockholder has complied with all
        the agreements and satisfied all the conditions on its part to be
        performed or satisfied at or prior to the Closing Date.



                                      -34-
<PAGE>

                        (m) The Company shall have requested and caused Ernst &
        Young LLP to have furnished to the Underwriters letters, at the
        Execution Time and at the Closing Date, dated respectively as of the
        Execution Time and as of the Closing Date (with the requisite procedures
        to be completed by such auditors no later than two Business Days prior
        to the Execution Time and the Closing Date), in form and substance
        reasonably satisfactory to the Representatives, confirming that they are
        an independent registered public accounting firm within the meaning of
        the Act and the applicable rules and regulations adopted by the
        Commission thereunder and that they are independent public accountants
        as required under Canadian Securities Laws, and that they have performed
        a review of the unaudited interim financial information of the Company
        and OccuLogix, L.P. for the nine-month period ended September 30, 2004
        and as at September 30, 2004, in accordance with Statement on Auditing
        Standards No. 100, and stating in effect that:

                                (i) in their opinion the audited financial
                        statements included in the Registration Statement and
                        the Prospectus and reported on by them comply as to form
                        in all material respects with the applicable accounting
                        requirements of the Act and the related rules and
                        regulations adopted by the Commission and with the
                        applicable accounting requirements of the Canadian
                        Securities Laws;

                                (ii) on the basis of a reading of the latest
                        unaudited financial statements made available by the
                        Company and its subsidiaries and OccuLogix, L.P.; their
                        limited review, in accordance with standards established
                        under Statement on Auditing Standards No. 100, of the
                        unaudited interim financial information for the
                        nine-month period ended September 30, 2004, and as at
                        September 30, 2004; carrying out certain specified
                        procedures (but not an examination in accordance with
                        U.S. generally accepted auditing standards) which would
                        not necessarily reveal matters of significance with
                        respect to the comments set forth in such letter; a
                        reading of the minutes of the meetings of the
                        stockholders, partners, board of directors, audit
                        committee and all other committees of the Company and
                        its subsidiaries and OccuLogix, L.P.; and inquiries of
                        certain officials of the Company and OccuLogix, L.P. who
                        have responsibility for financial and accounting matters
                        of the Company and its subsidiaries and OccuLogix, L.P.
                        as to transactions and events subsequent to September
                        30, 2004, nothing came to their attention which caused
                        them to believe that:

                                        (1) any unaudited financial statements
                                included in the Registration Statement and the
                                Prospectus do not comply as to form in all
                                material respects with applicable accounting
                                requirements of the Act and the Exchange Act and
                                with the related rules and regulations adopted
                                by the Commission and the applicable accounting
                                requirements of the Canadian Securities Laws
                                with respect to such financial statements; and
                                said unaudited financial statements are not in
                                conformity with U.S. generally



                                      -35-
<PAGE>

                                accepted accounting principles applied on a
                                basis substantially consistent with that of the
                                audited financial statements included in the
                                Registration Statement and the Prospectus; and


                                        (2) with respect to the period
                                subsequent to September 30, 2004, there were any
                                changes, at a specified date not more than two
                                days prior to the date of the letter, in the
                                capital stock of the Company or partners'
                                capital of OccuLogix, L.P., increases in due to
                                stockholders, convertible debentures due to
                                stockholders and long-term convertible
                                debentures of the Company and its subsidiaries
                                or increases in due to related parties of
                                OccuLogix, L.P. or increases in net current
                                liabilities or stockholders' deficiency of the
                                Company or increases in net current liabilities
                                or partners' deficit of OccuLogix, L.P. as
                                compared with the amounts shown on the September
                                30, 2004 consolidated balance sheet of the
                                Company and the September 30, 2004 balance sheet
                                of OccuLogix, L.P., as applicable, included in
                                the Registration Statement and the Prospectus,
                                or for the period from October 1, 2004 to such
                                specified date there were any decreases, as
                                compared with the corresponding period in the
                                preceding year, in revenues or increases, as
                                compared with the corresponding period in the
                                preceding year, in total or per share amounts of
                                net loss for the period of the Company and its
                                subsidiaries and OccuLogix, L.P., except in all
                                instances for changes, decreases or increases
                                set forth in such letter, in which case the
                                letter shall be accompanied by an explanation by
                                the Company or OccuLogix, L.P., as applicable,
                                as to the significance thereof unless said
                                explanation is not deemed necessary by the
                                Underwriters;

                                (iii) they have performed certain other
                        specified procedures as a result of which they
                        determined that certain information of an accounting,
                        financial or statistical nature (which is limited to
                        accounting, financial or statistical information derived
                        from the general accounting records of the Company and
                        its subsidiaries and OccuLogix, L.P.) set forth in the
                        Registration Statement, the U.S. Prospectus and the
                        Canadian Final Prospectus, including the information set
                        forth under the captions "Summary Historical and Pro
                        Forma Consolidated Financial Data," "Capitalization" and
                        "Selected Consolidated Financial Data" in the
                        Registration Statement and the Prospectus, agrees with
                        the accounting records of the Company and its
                        subsidiaries and OccuLogix, L.P., excluding any
                        questions of legal interpretation; and

                                (iv) on the basis of a reading of the unaudited
                        pro forma financial statements included in the
                        Registration Statement and the Prospectus (the "pro
                        forma financial statements"); carrying out certain
                        specified procedures; inquiries of certain officials of
                        the Company and OccuLogix, L.P. who have responsibility
                        for financial and accounting



                                      -36-
<PAGE>

                        matters; and proving the arithmetic accuracy of the
                        application of the pro forma adjustments to the
                        historical amounts in the pro forma financial
                        statements, nothing came to their attention which caused
                        them to believe that the pro forma financial statements
                        do not comply as to form in all material respects with
                        the applicable accounting requirements of Rule 11-02 of
                        Regulation S-X or the Canadian Securities Laws or that
                        the pro forma adjustments have not been properly applied
                        to the historical amounts in the compilation of such
                        statements.

                        References to the Prospectus in this paragraph (m)
                        include any supplement thereto at the date of the
                        letter.


                        (n) The Company shall have furnished to the Underwriters
        letters of its chief financial officer, at the Execution Time and at the
        Closing Date, dated respectively as of the Execution Time and as of the
        Closing Date, in form and substance reasonably satisfactory to the
        Representatives, stating his conclusions and findings with respect to
        financial information contained in the Prospectus and not otherwise
        covered by the letters described in Section 6(m) hereof.


                        (o) Subsequent to the Execution Time or, if earlier, the
        dates as of which information is given in the Registration Statement
        (exclusive of any amendment thereof), the U.S. Prospectus (exclusive of
        any supplement thereto) and the Canadian Prospectus, there shall not
        have been (i) any change or decrease specified in the letter or letters
        referred to in paragraph (m) of this Section 6 or (ii) any change, or
        any development involving a prospective change, in or affecting the
        condition (financial or otherwise), earnings, business or properties of
        the Company and its subsidiaries taken as a whole, whether or not
        arising from transactions in the ordinary course of business, except as
        set forth in or contemplated in the U.S. Prospectus (exclusive of any
        supplement thereto) and the Canadian Prospectus, and the Underwriters
        shall not have become aware of any undisclosed material adverse
        information relating to the Company and its subsidiaries, or other
        adverse material development, the effect of which, in any case referred
        to in clause (i) or (ii) above, is, in the sole judgment of the
        Underwriters, so material and adverse as to make it impractical or
        inadvisable to proceed with the offering or delivery of the Securities
        as contemplated by the Registration Statement (exclusive of any
        amendment thereof), the U.S. Prospectus (exclusive of any supplement
        thereto) and the Canadian Prospectus.


                        (p) Prior to the Closing Date, the Company and the
        Selling Stockholders shall have furnished to the Representatives such
        further information, certificates and documents as the Representatives
        may reasonably request.


                        (q) Subsequent to the Execution Time, there shall not
        have been any decrease in the rating of any of the Company's debt
        securities by any "nationally recognized statistical rating
        organization" (as defined for purposes of Rule 436(g) under the Act) or
        any notice given of any intended or potential decrease in any such
        rating or of a possible change in any such rating that does not indicate
        the direction of the possible change.



                                      -37-
<PAGE>

                        (r) The Securities shall have been approved for
        quotation on the Nasdaq National Market, subject only to official notice
        of issuance.


                        (s) The Securities shall be listed and posted for
        trading on the TSX at the opening of trading on the Closing Date.


                        (t) At or prior to the Execution Time, the Company shall
        have furnished to the Representatives a letter substantially in the form
        of Exhibit A hereto from each officer and director of the Company and
        each Major Selling Stockholder addressed to the Underwriters.


                        (u) At or prior to the Execution Time, each of the
        transactions included in the Reorganization (as defined and described in
        the Prospectus) shall have been completed to the satisfaction of the
        Underwriters and their counsel.


                        (v) The Company shall have requested and caused
        Desjardins Ducharme Stein Monast to have furnished to the Underwriters
        an opinion, dated the Closing Date and addressed to the Underwriters and
        their counsel, in form and substance reasonably satisfactory to the
        Underwriters and their counsel, regarding compliance with all the laws
        of the Province of Quebec relating to the use of the French language in
        connection with the documents (including the Canadian Prospectus, any
        Supplementary Material, forms of order and confirmation and certificates
        representing the Securities) to be delivered to purchasers of the
        Securities in the Province of Quebec.


                        (w) The Underwriters shall have received on the Closing
        Date such other certificates, statutory declarations, agreements or
        materials, in form and substance reasonably satisfactory to the
        Underwriters and their counsel, as the Underwriters and their counsel
        may reasonably request.

                If any of the conditions specified in this Section 6 shall not
have been fulfilled when and as provided in this Agreement, or if any of the
opinions and certificates mentioned above or elsewhere in this Agreement shall
not be reasonably satisfactory in form and substance to the Underwriters and
counsel for the Underwriters, this Agreement and all obligations of the
Underwriters hereunder may be canceled at, or at any time prior to, the Closing
Date by the Representatives. Notice of such cancellation shall be given to the
Company and each Selling Stockholder in writing or by telephone or facsimile
confirmed in writing.

                The documents required to be delivered by this Section 6 shall
be delivered at the office of Piper Rudnick LLP, U.S. counsel for the
Underwriters, at 1251 Avenue of the Americas, New York, New York 10020,
Attention: Marjorie Sybul Adams, on the Closing Date.

                7. Reimbursement of Underwriters' Expenses. If the sale of the
Securities provided for herein is not consummated because any condition to the
obligations of the Underwriters set forth in Section 6 hereof is not satisfied,
because of any termination pursuant to Section 10 hereof or because of any
refusal, inability or failure on the part of the Company or any Selling
Stockholders to perform any agreement herein or comply with any provision hereof
other than by reason of a default by any of the Underwriters, the Company will
reimburse the Underwriters severally through Citigroup Global Markets Inc. on
demand for all out-of-pocket expenses



                                      -38-
<PAGE>

(including reasonable fees and disbursements of counsel) that shall have been
incurred by them in connection with the proposed purchase and sale of the
Securities. If the Company is required to make any payments to the Underwriters
under this Section 7 because of any Selling Stockholder's refusal, inability or
failure to satisfy any condition to the obligations of the Underwriters set
forth in Section 6, the Selling Stockholders pro rata in proportion to the
percentage of Securities to be sold by each shall reimburse the Company on
demand for all amounts so paid.

        8. Indemnification and Contribution.

                        (a) The Company and each of the Major Selling
        Stockholders jointly and severally agree to indemnify and hold harmless
        each Underwriter, the directors, officers, employees and agents of each
        Underwriter and each person who controls any Underwriter within the
        meaning of either the Act or the Exchange Act against any and all
        losses, claims, damages or liabilities, joint or several, to which they
        or any of them may become subject under the Act, the Exchange Act,
        Canadian Securities Laws or any other Federal, state or provincial
        statutory law or regulation, at common law or otherwise, insofar as such
        losses, claims, damages or liabilities (or actions in respect thereof)
        arise out of or are based upon any untrue statement or alleged untrue
        statement of a material fact contained in the registration statement for
        the registration of the Securities as originally filed or in any
        amendment thereof, or in the U.S. Preliminary Prospectus, the Canadian
        Preliminary Prospectus, the Canadian Final Prospectus, the Canadian
        Supplemental PREP Prospectus or the Prospectus, or in any amendment
        thereof or supplement thereto, or arise out of or are based upon the
        omission or alleged omission to state therein a material fact required
        to be stated therein or necessary to make the statements therein not
        misleading, and agree to reimburse each such indemnified party, as
        incurred, for any legal or other expenses reasonably incurred by them in
        connection with investigating or defending any such loss, claim, damage,
        liability or action; provided, however, that the Company and the
        -------- ------- Major Selling Stockholders will not be liable in any
        such case to the extent that any such loss, claim, damage or liability
        arises out of or is based upon any such untrue statement or alleged
        untrue statement or omission or alleged omission made therein in
        reliance upon and in conformity with written information furnished to
        the Company by or on behalf of any Underwriter through the
        Representatives specifically for inclusion therein. This indemnity
        agreement will be in addition to any liability which the Company or the
        Major Selling Stockholders may otherwise have.

                        (b) Each Other Selling Stockholder severally agrees to
        indemnify and hold harmless the Company, each of its directors, each of
        its officers who signs the Registration Statement, each Underwriter, the
        directors, officers, employees and agents of each Underwriter and each
        person who controls the Company or any Underwriter within the meaning of
        either the Act or the Exchange Act and each other Selling Stockholder,
        if any, to the same extent as the foregoing indemnity from the Company
        and the Major Selling Stockholders to each Underwriter, but only with
        reference to written information furnished to the Company by or on
        behalf of such Other Selling Stockholder specifically for inclusion in
        the documents referred to in the foregoing indemnity. This indemnity


                                      -39-
<PAGE>

        agreement will be in addition to any liability which any Other Selling
        Stockholder may otherwise have.

                        (c) Each Underwriter severally and not jointly agrees to
        indemnify and hold harmless the Company, each of its directors, each of
        its officers who signs the Registration Statement, and each person who
        controls the Company within the meaning of either the Act or the
        Exchange Act and each Selling Stockholder, to the same extent as the
        foregoing indemnity to each Underwriter, but only with reference to
        written information relating to such Underwriter furnished to the
        Company by or on behalf of such Underwriter through the Representatives
        specifically for inclusion in the documents referred to in the foregoing
        indemnity. This indemnity agreement will be in addition to any liability
        which any Underwriter may otherwise have. The Company and each Selling
        Stockholder acknowledge that the statements set forth in the last
        paragraph of the cover page regarding delivery of the Securities and,
        under the heading "Underwriting," (i) the list of Underwriters and their
        respective participation in the sale of the Securities, (ii) the
        sentences related to concessions and reallowances and (iii) the
        paragraph related to stabilization, syndicate covering transactions and
        penalty bids in any Preliminary Prospectus and the Prospectus constitute
        the only information furnished in writing by or on behalf of the several
        Underwriters for inclusion in any Preliminary Prospectus or the
        Prospectus.

                        (d) The Company agrees to indemnify and hold harmless
        Citigroup Global Markets Inc., the directors, officers, employees and
        agents of Citigroup Global Markets Inc. and each person, who controls
        Citigroup Global Markets Inc. within the meaning of either the Act or
        the Exchange Act ("Citigroup Entities"), from and against any and all
        losses, claims, damages and liabilities to which they may become subject
        under the Act, the Exchange Act or other Federal or state statutory law
        or regulation, at common law or otherwise (including, without
        limitation, any legal or other expenses reasonably incurred in
        connection with defending or investigating any such action or claim),
        insofar as such losses, claims damages or liabilities (or actions in
        respect thereof) (i) arise out of or are based upon any untrue statement
        or alleged untrue statement of a material fact contained in the
        prospectus wrapper material prepared by or with the consent of the
        Company for distribution in foreign jurisdictions in connection with the
        Directed Share Program attached to the Prospectus or any preliminary
        prospectus, or arise out of or are based upon the omission or alleged
        omission to state therein a material fact required to be stated therein
        or necessary to make the statement therein, when considered in
        conjunction with the Prospectus or any applicable preliminary
        prospectus, not misleading; (ii) caused by the failure of any
        Participant to pay for and accept delivery of the securities which
        immediately following the Effective Date of the Registration Statement,
        were subject to a properly confirmed agreement to purchase; or (iii)
        related to, arising out of, or in connection with the Directed Share
        Program, except that this clause (iii) shall not apply to the extent
        that such loss, claim, damage or liability is finally judicially
        determined to have resulted primarily from the gross negligence or
        willful misconduct of the Citigroup Entities.

                        (e) Promptly after receipt by an indemnified party under
        this Section 8 of notice of the commencement of any action, such
        indemnified party will, if a claim in



                                      -40-
<PAGE>

        respect thereof is to be made against the indemnifying party under this
        Section 8, notify the indemnifying party in writing of the commencement
        thereof; but the failure so to notify the indemnifying party (i) will
        not relieve it from liability under paragraph (a), (b) (c) or (d) above
        unless and to the extent it did not otherwise learn of such action and
        such failure results in the forfeiture by the indemnifying party of
        substantial rights and defenses and (ii) will not, in any event, relieve
        the indemnifying party from any obligations to any indemnified party
        other than the indemnification obligation provided in paragraph (a),
        (b), (c) or (d) above. The indemnifying party shall be entitled to
        appoint counsel of the indemnifying party's choice at the indemnifying
        party's expense to represent the indemnified party in any action for
        which indemnification is sought (in which case the indemnifying party
        shall not thereafter be responsible for the fees and expenses of any
        separate counsel retained by the indemnified party or parties except as
        set forth below); provided, -------- however, that such counsel shall be
        reasonably satisfactory to the indemnified ------- party.
        Notwithstanding the indemnifying party's election to appoint counsel to
        represent the indemnified party in an action, the indemnified party
        shall have the right to employ separate counsel (including local
        counsel), and the indemnifying party shall bear the reasonable fees,
        costs and expenses of such separate counsel if (i) the use of counsel
        chosen by the indemnifying party to represent the indemnified party
        would present such counsel with a conflict of interest, (ii) the actual
        or potential defendants in, or targets of, any such action include both
        the indemnified party and the indemnifying party and the indemnified
        party shall have reasonably concluded based on advice of counsel that
        there may be legal defenses available to it and/or other indemnified
        parties which are different from or additional to those available to the
        indemnifying party, (iii) the indemnifying party shall not have employed
        counsel reasonably satisfactory to the indemnified party to represent
        the indemnified party within a reasonable time after notice of the
        institution of such action or (iv) the indemnifying party shall
        authorize the indemnified party to employ separate counsel at the
        expense of the indemnifying party. An indemnifying party will not,
        without the prior written consent of the indemnified parties, settle or
        compromise or consent to the entry of any judgment with respect to any
        pending or threatened claim, action, suit or proceeding in respect of
        which indemnification or contribution may be sought hereunder (whether
        or not the indemnified parties are actual or potential parties to such
        claim or action) unless such settlement, compromise or consent includes
        an unconditional release of each indemnified party from all liability
        arising out of such claim, action, suit or proceeding. It is understood
        that the indemnifying party shall not, in connection with any proceeding
        or related proceedings in the same jurisdiction, be liable for the
        reasonable fees and expenses of more than one separate firm for all such
        indemnified parties. Such firm shall be designated in writing by the
        Representatives in the case of parties indemnified pursuant to paragraph
        (a) or (d) and by the Company in the case of parties indemnified
        pursuant to paragraph (b) or (c). The indemnifying party shall not be
        liable for any settlement of any proceeding effected without its written
        consent but if settled with such consent or if there be a final judgment
        for the plaintiff, the indemnifying party agrees to indemnify the
        indemnified party from and against any loss or liability by reason of
        such settlement or judgment.

        Notwithstanding anything contained herein to the contrary, if indemnity
        may be sought pursuant to Section 8(d) hereof in respect of such action
        or proceeding, then in addition to such separate firm for the
        indemnified parties, the indemnifying party shall be liable for



                                      -41-
<PAGE>

        the reasonable fees and expenses of not more than one separate firm (in
        addition to any local counsel) for Citigroup Global Markets Inc., the
        directors, officers, employees and agents of Citigroup Global Markets
        Inc., and all persons, if any, who control Citigroup Global Markets Inc.
        within the meaning of either the Act or the Exchange Act for the defense
        of any losses, claims, damages and liabilities arising out of the
        Directed Share Program.

                        (f) In the event that the indemnity provided in
        paragraph (a), (b) (c) or (d) of this Section 8 is unavailable to or
        insufficient to hold harmless an indemnified party for any reason, the
        Company and the Major Selling Stockholders, jointly and severally, the
        Other Selling Stockholders severally and the Underwriters severally
        agree to contribute to the aggregate losses, claims, damages and
        liabilities (including legal or other expenses reasonably incurred in
        connection with investigating or defending same) (collectively "Losses")
        to which the Company, the Major Selling Stockholders, the Other Selling
        Stockholders and one or more of the Underwriters may be subject in such
        proportion as is appropriate to reflect the relative benefits received
        by the Company, the Major Selling Stockholders and the Other Selling
        Stockholders on the one hand and by the Underwriters on the other from
        the offering of the Securities; provided, however, that in no case shall
        any Underwriter (except as may be provided -------- ------- in any
        agreement among underwriters relating to the offering of the Securities)
        be responsible for any amount in excess of the underwriting discount or
        commission applicable to the Securities purchased by such Underwriter
        hereunder. If the allocation provided by the immediately preceding
        sentence is unavailable for any reason, the Company and the Major
        Selling Stockholders, jointly and severally, the Other Selling
        Stockholders severally and the Underwriters severally shall contribute
        in such proportion as is appropriate to reflect not only such relative
        benefits but also the relative fault of the Company, the Major Selling
        Stockholders and the Other Selling Stockholders on the one hand and of
        the Underwriters on the other in connection with the statements or
        omissions which resulted in such Losses as well as any other relevant
        equitable considerations. Benefits received by the Company and the
        Selling Stockholders shall be deemed to be equal to the total net
        proceeds from the offering (before deducting expenses) received by them,
        and benefits received by the Underwriters shall be deemed to be equal to
        the total underwriting discounts and commissions, in each case as set
        forth on the cover page of the Prospectus. Relative fault shall be
        determined by reference to, among other things, whether any untrue or
        any alleged untrue statement of a material fact or the omission or
        alleged omission to state a material fact relates to information
        provided by the Company or the Selling Stockholders on the one hand or
        the Underwriters on the other, the intent of the parties and their
        relative knowledge, access to information and opportunity to correct or
        prevent such untrue statement or omission. The Company, the Selling
        Stockholders and the Underwriters agree that it would not be just and
        equitable if contribution were determined by pro rata allocation or any
        other method of allocation which does not take account of the equitable
        considerations referred to above. Notwithstanding the provisions of this
        paragraph (f), no person guilty of fraudulent misrepresentation (within
        the meaning of Section 11(f) of the Act) shall be entitled to
        contribution from any person who was not guilty of such fraudulent
        misrepresentation. For purposes of this Section 8, each person who
        controls an Underwriter within the meaning of either the Act or the
        Exchange Act and each director, officer, employee and agent of an
        Underwriter shall have the same



                                      -42-
<PAGE>



        rights to contribution as such Underwriter, and each person who controls
        the Company within the meaning of either the Act or the Exchange Act,
        each officer of the Company who shall have signed the Registration
        Statement and each director of the Company shall have the same rights to
        contribution as the Company, subject in each case to the applicable
        terms and conditions of this paragraph (f).

                        (g) The liability of each Selling Stockholder under such
        Selling Stockholder's representations and warranties contained in
        Section 1 hereof and under the indemnity and contribution agreements
        contained in this Section 8 shall be limited to an amount equal to the
        initial public offering price of the Securities sold by such Selling
        Stockholder to the Underwriters. The Company and the Selling
        Stockholders may agree, as among themselves and without limiting the
        rights of the Underwriters under this Agreement, as to the respective
        amounts of such liability for which they each shall be responsible.

        9. Default by an Underwriter. If any one or more Underwriters shall fail
to purchase and pay for any of the Securities agreed to be purchased by such
Underwriter or Underwriters hereunder and such failure to purchase shall
constitute a default in the performance of its or their obligations under this
Agreement, the remaining Underwriters shall be obligated severally to take up
and pay for (in the respective proportions which the amount of Securities set
forth opposite their names in Schedule I hereto bears to the aggregate amount of
Securities set forth opposite the names of all the remaining Underwriters) the
Securities which the defaulting Underwriter or Underwriters agreed but failed to
purchase; provided, however, that in the event that the aggregate amount of
Securities which the defaulting Underwriter or Underwriters agreed but failed to
purchase shall exceed 10% of the aggregate amount of Securities set forth in
Schedule I hereto, the remaining Underwriters shall have the right to purchase
all, but shall not be under any obligation to purchase any, of the Securities,
and if such nondefaulting Underwriters do not purchase all the Securities, this
Agreement will terminate without liability to any nondefaulting Underwriter, the
Selling Stockholders or the Company. In the event of a default by any
Underwriter as set forth in this Section 9, the Closing Date shall be postponed
for such period, not exceeding five Business Days, as the Representatives shall
determine in order that the required changes in the Registration Statement and
the Prospectus or in any other documents or arrangements may be effected.
Nothing contained in this Agreement shall relieve any defaulting Underwriter of
its liability, if any, to the Company, the Selling Stockholders and any
nondefaulting Underwriter for damages occasioned by its default hereunder.

        10. Termination. This Agreement shall be subject to termination in the
absolute discretion of the Representatives, by notice given to the Company prior
to delivery of and payment for the Securities, if at any time prior to such time
(i) (x) trading in the Company's Common Stock shall have been suspended by the
Commission, any of the Canadian Securities Commissions, the Nasdaq National
Market or the TSX or trading in securities generally on the New York Stock
Exchange, the Nasdaq National Market or (y) the TSX shall have been suspended or
limited or minimum prices shall have been established on such Exchange, the
Nasdaq National Market or the TSX, (ii) a banking moratorium shall have been
declared either by Federal, New York State or Canadian authorities or (iii)
there shall have occurred any outbreak or escalation of hostilities, declaration
by the United States or Canada of a national emergency or war, or other calamity
or crisis the effect of which on financial markets is such as






                                      -43-
<PAGE>

to make it, in the sole judgment of the Representatives, impractical or
inadvisable to proceed with the offering or delivery of the Securities as
contemplated by the Prospectus (exclusive of any supplement thereto).

        11. Representations and Indemnities to Survive. The respective
agreements, representations, warranties, indemnities and other statements of the
Company or its officers, of each Selling Stockholder and of the Underwriters set
forth in or made pursuant to this Agreement will remain in full force and
effect, regardless of any investigation made by or on behalf of any Underwriter,
any Selling Stockholder or the Company or any of the officers, directors,
employees, agents or controlling persons referred to in Section 8 hereof, and
will survive delivery of and payment for the Securities. The provisions of
Sections 7 and 8 hereof shall survive the termination or cancellation of this
Agreement.


        12. Notices. All communications hereunder will be in writing and
effective only on receipt, and, if sent to the Representatives, will be mailed,
delivered or telefaxed to the Citigroup Global Markets Inc. General Counsel (fax
no.: (212) 816-7912) and confirmed to Citigroup Global Markets Inc., at 388
Greenwich Street, New York, New York 10013, Attention: General Counsel; or, if
sent to the Company, will be mailed, delivered or telefaxed to OccuLogix, Inc.,
2600 Skymark Drive, Unit 9, Suite 201, Mississauga, Ontario L4N 5B2, Attention:
Chief Executive Officer (fax no.: (905) 602-7623); or if sent to any Selling
Stockholder, will be mailed, delivered or telefaxed and confirmed to it at the
address set forth in Schedule II hereto.

        13. Successors. This Agreement will inure to the benefit of and be
binding upon the parties hereto and their respective successors and the
officers, directors, employees, agents and controlling persons referred to in
Section 8 hereof, and no other person will have any right or obligation
hereunder.

        14. Applicable Law. This Agreement will be governed by and construed in
accordance with the laws of the State of New York applicable to contracts made
and to be performed within the State of New York.

        15. Counterparts. This Agreement may be signed in one or more
counterparts, each of which shall constitute an original and all of which
together shall constitute one and the same agreement.

        16. Headings. The section headings used herein are for convenience only
and shall not affect the construction hereof.

        17. Definitions. The terms which follow, when used in this Agreement,
shall have the meanings indicated.

                        "Act" shall mean the Securities Act of 1933, as amended,
        and the rules and regulations of the Commission promulgated thereunder.

                        "Business Day" shall mean any day other than a Saturday,
        a Sunday or a legal holiday or a day on which banking institutions or
        trust companies are authorized or obligated by law to close in New York,
        New York or Toronto, Ontario.



                                      -44-
<PAGE>

                        "Canadian Securities Commissions" means, collectively,
        the securities commissions or other securities regulatory authorities in
        each of the Canadian Qualifying Jurisdictions.

                        "Canadian Securities Laws" means all applicable
        securities laws in each of the Canadian Qualifying Jurisdictions
        emanating from Governmental Authorities, including the respective rules
        and regulations made thereunder together with applicable published
        national and local instruments, policy statements, notices, blanket
        rulings and orders of the Canadian Securities Commissions, all
        discretionary rulings and orders applicable to the Company, if any, of
        the Canadian Securities Commissions and all rules, by-laws and
        regulations governing the TSX, all as the same are in effect at the date
        hereof and as amended, supplemented or replaced from time to time during
        the period of Distribution.

                        "Commission" shall mean the Securities and Exchange
        Commission.

                        "Distribution" means "distribution" or "distribution to
        the public" of the Securities as those terms are defined in Canadian
        Securities Laws.

                        "Effective Date" shall mean each date and time that the
        Registration Statement, any post-effective amendment or amendments
        thereto and any Rule 462(b) Registration Statement became or become
        effective.

                        "Exchange Act" shall mean the Securities Exchange Act of
        1934, as amended, and the rules and regulations of the Commission
        promulgated thereunder.

                        "Execution Time" shall mean the date and time that this
        Agreement is executed and delivered by the parties hereto.

                        "Governmental Authority" means any (a) multinational,
        federal, provincial, state, regional, municipal, local or other
        government, governmental or public department, central bank, court,
        tribunal, arbitral body, bureau or agency, domestic or foreign, (b) any
        subdivision, agent, commission, board, or authority of any of the
        foregoing, or (c) any quasi- governmental or private body exercising any
        regulatory, expropriation or taxing authority under or for the account
        of any of the foregoing, and any stock exchange or self-regulatory
        authority and, for greater certainty, includes the Canadian Securities
        Commissions, the TSX, Market Regulation Services Inc. and the FDA.

                        "Laws" means applicable securities laws and all other
        statutes, regulations, statutory rules, orders, by-laws, codes,
        ordinances, decrees, the terms and conditions of any grant of approval,
        permission, authority or license, or any judgment, order, decision,
        ruling, award, policy or guideline, of any Governmental Authority, and
        the term "applicable" with respect to such Laws and in the context that
        refers to one or more persons, means that such Laws apply to such person
        or persons or its or their business, undertaking, property or securities
        and emanate from a Governmental Authority, having jurisdiction over the
        person or persons or its or their business, undertaking, property or
        securities.



                                      -45-
<PAGE>

                        "MRRS" means the mutual reliance review system
        procedures provided for under National Policy 43-201 - Mutual Reliance
        Review System for Prospectuses and Annual Information Forms.

                        "Preliminary U.S. Prospectus" shall mean any preliminary
        prospectus referred to in paragraph l(i)(a) above and any preliminary
        prospectus included in the Registration Statement at the Effective Date
        that omits Rule 430A Information.

                        "Registration Statement" shall mean the registration
        statement referred to in paragraph 1(i)(a) above, including exhibits and
        financial statements, as amended at the Execution Time (or, if not
        effective at the Execution Time, in the form in which it shall become
        effective) and, in the event any post-effective amendment thereto or any
        Rule 462(b) Registration Statement becomes effective prior to the
        Closing Date, shall also mean such registration statement as so amended
        or such Rule 462(b) Registration Statement, as the case may be. Such
        term shall include any Rule 430A Information deemed to be included
        therein at the Effective Date as provided by Rule 430A.

                        "Rule 424", "Rule 430A" and "Rule 462" refer to such
        rules under the Act.

                        "Rule 430A Information" shall mean information with
        respect to the Securities and the offering thereof permitted to be
        omitted from the Registration Statement when it becomes effective
        pursuant to Rule 430A.

                        "Rule 462(b) Registration Statement" shall mean a
        registration statement and any amendments thereto filed pursuant to Rule
        462(b) relating to the offering covered by the registration statement
        referred to in Section 1(a) hereof.

                        "Selling Firms" means such investment dealers and
        brokers through which the Underwriters may sell Securities to the public
        under the terms of this Agreement.

                        "Taxes" includes all forms of taxation (including,
        without limitation, any net income or gains, minimum, gross income,
        gross receipts, sales, use, ad valorem, value-added, transfer,
        franchise, profits, license, withholding, payroll, employment, excise,
        severance, stamp, capital stock, occupation, property, custom,
        environmental or windfall tax or duty), together with interest,
        penalties and additions imposed with respect to the foregoing, imposed
        by any local, municipal, state, provincial, Federal or other government,
        governmental entity or political subdivision, whether of Canada, the
        United States or other country or political unit.

                        "Tax Return" means all returns, declarations,
        statements, reports, schedules, forms and information returns, whether
        original or amended, relating to Taxes.

                        "TSX" means the Toronto Stock Exchange.

                        "U.S. Prospectus" shall mean the prospectus relating to
        the Securities that is first filed pursuant to Rule 424(b) after the
        Execution Time or, if no filing pursuant to



                                      -46-
<PAGE>

        Rule 424(b) is required, shall mean the form of final prospectus
        relating to the Securities included in the Registration Statement at the
        Effective Date.











                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]






                                      -47-
<PAGE>

                If the foregoing is in accordance with your understanding of our
agreement, please sign and return to us the enclosed duplicate hereof, whereupon
this letter and your acceptance shall represent a binding agreement among the
Company, the Selling Stockholders and the several Underwriters.

                               Very truly yours,

                               OCCULOGIX, INC.


                               By:
                                  -------------------------------------------
                                  Name:
                                  Title:



                               SELLING STOCKHOLDERS LISTED ON SCHEDULE II HERETO





                               By:
                                  --------------------------------
                                  Elias Vamvakas, as Attorney-in-Fact
                                  acting on behalf of the Selling
                                  Stockholders



                               By:
                                  --------------------------------
                                  William G. Dumencu, CA, as
                                  Attorney-in-Fact acting on behalf of
                                  the Selling Stockholders



<PAGE>



The foregoing Agreement is hereby
confirmed and accepted as of the
date first above written.

Citigroup Global Markets Inc.
SG Cowen & Co., LLC
ThinkEquity Partners LLC

By:   Citigroup Global Markets Inc.


By:
   -----------------------------------------
   Name:
   Title:

For themselves and the other several
Underwriters named in Schedule I to
the foregoing Agreement.


<PAGE>

                                   SCHEDULE I


<Table>
<Caption>
                                                        NUMBER OF UNDERWRITTEN
UNDERWRITERS                                          SECURITIES TO BE PURCHASED
-------------------------------------------           --------------------------
<S>                                                   <C>

Citigroup Global Markets Inc.......................

SG Cowen & Co., LLC................................

ThinkEquity Partners LLC...........................

Orion Securities (USA) Inc.........................

DeMatteo Monness LLC...............................

Citigroup Global Markets Canada Inc................

Clarus Securities Inc..............................

Orion Securities Inc...............................

Octagon Capital Corporation........................



                                                              ------------
                      TOTAL........................
                                                              ============
</Table>


<PAGE>

                                   SCHEDULE II



Unless otherwise noted, each person's address is:
c/o OccuLogix, Inc., 2600 Skymark Drive, Unit 9, Suite 201
Mississauga, Ontario L4N 5B2





<Table>
<Caption>
                                                NUMBER OF UNDERWRITTEN           MAXIMUM NUMBER OF OPTION
    MAJOR SELLING STOCKHOLDERS                   SECURITIES TO BE SOLD            SECURITIES TO BE SOLD
----------------------------------             ---------------------------      --------------------------
<S>                                            <C>                              <C>

TLC Vision Corporation
5280 Solar Drive, Suite 100,
Mississauga, Ontario
L4W 5M8..................                                2,329,031                           3,382,927


Richard Davis, MD..................                        157,365                             228,574


John Cornish..................                              32,637                              47,405
</TABLE>



<TABLE>
<CAPTION>
                                                NUMBER OF UNDERWRITTEN           MAXIMUM NUMBER OF OPTION
    OTHER SELLING STOCKHOLDERS                   SECURITIES TO BE SOLD            SECURITIES TO BE SOLD
----------------------------------             ---------------------------      --------------------------
<S>                                            <C>                              <C>

Bermuda Bay, Ltd. (Alberto de
Alejo) ..................

Daniel Bertoch, D.D.S...................

Tom Brandt..................

Sandra Bruck..................

Margaret Cornish..................

Ramia Cornish..................

Margaret Cornish QDOT
Trust..................

Dana Deupree..................

Larry Dewberry..................

David Dieters..................
</TABLE>




<PAGE>

<TABLE>
<S>                                             <C>                              <C>
Burt Dubow..................

Alexander Eaton, M.D...................

Richard Fielder..................

Richard & Brigitte
Fielder..................

Patrick Flaherty, M.D...................

David Geller, M.D...................

James Gills, M.D...................

James P. Gills Flint
Trust..................

Ray Gonzalez..................

Alan & Debra Green..................

Richard Hairston..................

Thomas Hooker..................

Susan B. Howard..................

David Israel..................

Charles Jenkins..................

Carol Jones..................

Charles L. Jones..................

W. Andrew Krusen..................

Merit Partners (Jeffrey
Schoenbaum)..................

Angela Metelski..................

Julie & Matt Mores..................

Julie Mores..................

Matt Mores..................

Robin Morrison..................
</TABLE>




                                      -2-
<PAGE>

<TABLE>
<S>                                             <C>                              <C>
Donna M. Muller............

Michael Murray..................

Sandara Murray..................

Northlea Partners (Dr. John
Abeles)..................

Rula Peindado..................

Nancie Reichle..................

Kris Richards, Jr., M.D...................

A.H. Rodriguez..................

Christopher Rodriguez..................

Donna Rodriguez..................

Jennifer Rodriguez..................

Rodriguez Family Trust,
A.H...................

Donna Rodriguez Family
Trust..................

Safe Harbor Fund, L.P. (Dean G.
Tanella)..................

Safe Harbor Managed Account
101-A, Ltd. (Gary Saling)..................

Paul Scharfer..................

Jeffrey Schwartz..................

Jane Cornish Smith..................

Mark Stern..................

Mark Stern & Ellen
Kaplan..................

Don Strickland..................

S.M. Weinstock..................
</TABLE>



                                      -3-
<PAGE>


<TABLE>
<S>                                     <C>                   <C>
Leslie Wells..................

Barbara White..................

Elizabeth White..................
</TABLE>



                                        ------------          ------------
                      TOTAL
                                        ============          ============





                                      -4-
<PAGE>


                                     ANNEX A



                            SIGNIFICANT SUBSIDIARIES


OccuLogix Holdings, Inc.                                  Delaware

OccuLogix, L.P.                                           Delaware

OccuLogix LLC                                             Delaware

OccuLogix Management, Inc.                                Delaware

OccuLogix ExchangeCo ULC                                  Nova Scotia







<PAGE>


[FORM OF LOCK-UP AGREEMENT]                                            EXHIBIT A


              [Letterhead of officer, director or major stockholder
                               of OccuLogix, Inc.]

                                 OccuLogix, Inc.
                         Public Offering of Common Stock

                                                                          , 2004
                                                    --------------- ------

Citigroup Global Markets Inc.
SG Cowen & Co., LLC
ThinkEquity Partners LLC
As Representatives of the several Underwriters,
c/o Citigroup Global Markets Inc.
388 Greenwich Street
New York, New York 10013

Ladies and Gentlemen:

        This letter is being delivered to you in connection with the proposed
Underwriting Agreement (the "Underwriting Agreement"), between OccuLogix, Inc.,
a Delaware corporation (the "Company"), and each of you as representatives of a
group of Underwriters named therein, relating to an underwritten public offering
(the "Offering") of Common Stock, $0.001 par value (the "Common Stock"), of the
Company.

        In order to induce you and the other Underwriters to enter into the
Underwriting Agreement, the undersigned will not, without the prior written
consent of Citigroup Global Markets Inc., offer, sell, contract to sell, pledge
or otherwise dispose of, (or enter into any transaction which is designed to, or
might reasonably be expected to, result in the disposition (whether by actual
disposition or effective economic disposition due to cash settlement or
otherwise) by the undersigned or any affiliate of the undersigned or any person
in privity with the undersigned or any affiliate of the undersigned), directly
or indirectly, including the filing (or participation in the filing) of a
registration statement with the Securities and Exchange Commission in respect
of, or establish or increase a put equivalent position or liquidate or decrease
a call equivalent position within the meaning of Section 16 of the Securities
Exchange Act of 1934, as amended, and the rules and regulations of the
Securities and Exchange Commission promulgated thereunder with respect to, any
shares of capital stock of the Company or any securities convertible into, or
exercisable or exchangeable for such capital stock, or publicly announce an
intention to effect any such transaction:

        (i)  in the event that the undersigned is not a selling stockholder
             that will be executing the Underwriting Agreement, for the
             period from the date hereof until 180 days after the date of the
             Underwriting Agreement, other than shares of Common Stock
             disposed of as bona fide gifts approved by Citigroup Global
             Markets Inc.; and



                                      -2-
<PAGE>

        (ii) in the event that the undersigned is a selling stockholder that
             will be executing the Underwriting Agreement, for the period
             from the date hereof until the Underwriting Agreement is
             executed by such selling stockholder.

        This agreement shall automatically terminate and be of no further force
or effect upon the earlier of (i) an Underwriting Agreement not being executed
within 270 days of the date hereof; and (ii) either the Company or the
representatives of the group of Underwriters notifying the other in writing that
they are abandoning the Offering. If for any reason the Underwriting Agreement
shall be terminated prior to the Closing Date (as defined in the Underwriting
Agreement), the agreement set forth above shall likewise be terminated.

                                        Yours very truly,

                                        [SIGNATURE OF OFFICER, DIRECTOR OR MAJOR
                                        STOCKHOLDER]

[Name and address of officer, director or major stockholder]


                                      -3-