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                                                                   EXHIBIT 10.12

                      PATENT LICENSE AND ROYALTY AGREEMENT

            THIS AGREEMENT (the "Agreement") is made by and between OccuLogix,
Inc. (formerly Vascular Sciences Corporation), a Delaware Corporation (the
"Licensee"), and Hans Stock ("Stock") living in Germany, who is the assignee of
the rights of Prof. Dr. Helmut Borberg ("Borberg"), listed as inventor along
with Dr. Richard Brunner ("Brunner") in US patent application 09/000,917, which
is the parent application of US letters patent 6,245,038 issued June 12, 2001
(the "Patent").

            WHEREAS, Brunner executed a patent license and royalty agreement
with a predecessor of the Licensee as of May 6, 2002 and amended and restated
that agreement as of the date hereof;

            WHEREAS, Borberg assigned all his right, title and interest to the
Patent and the Patent Rights to Stock;

            WHEREAS, Stock originally licensed any and all of his rights, title
and interests to the Patent and the Patent Rights to the Licensee in an
undocumented oral agreement;

            WHEREAS, Stock executed a patent license and royalty agreement with
Licensee as of August 6, 2004 and amended and restated that agreement as of the
date hereof;

            WHEREAS, Stock continues to desire to license any and all of his
rights, title and interest to the Patent and the Patent Rights derived therefrom
to Licensee, and

            WHEREAS, Licensee continues to desire to obtain an exclusive license
to all of Stock's interest in the Patent and the Patent Rights derived therefrom
and to exclusively own the License to any and all of his rights, title,
interests and ownership to the Patent and any and all related patents, rights
and inventions that specifically relate to the Patent whether owned now or at
any time in the future by Stock (the "License"), and

            WHEREAS, Stock shall be eligible to receive any and all
consideration and compensation from the Licensee, such as those pledged to be
made by the Licensee to Stock under the terms of this Agreement.

            NOW THEREFORE, in consideration for guaranteed Advance Royalty
Payments and Royalty Payments as described below, and other good and valuable
consideration, the parties agree as follows:

1.    Patent Rights. Shall mean any and all of Stock's rights, title, ownership
      and interests in and to US letters patent 6,245,038 and any and all
      inventions, modifications, continuations-in-part, extensions, divisions,
      improvements, etc. made by Stock or his agents, in any and all areas that
      relate directly to the Patent, regardless of whether such inventions or
      improvements are patentable or may become patented; all inventions,
      modifications, continuations-in-part, extensions, divisions, improvements,
      etc. shall automatically be incorporated herein without the payment of any
      additional fees, royalties or any other compensation or considerations of
      any kind.

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2.    License Grant. Stock confirms that he has exclusively licensed, and does
      hereby continue to exclusively license, in accordance with the terms set
      forth below, unto Licensee, Stock's entire undivided right, title,
      ownership and interest in and to the Patent and the Patent Rights,
      throughout the Territory, to be held and enjoyed by Licensee the same as
      it would have been held and enjoyed by Stock if this Patent License and
      Royalty Agreement had not been made and entered into. The exclusive
      license granted herein also includes an exclusive right for the Licensee
      to grant expressly or implicitly, directly or through its subsidiaries or
      affiliates, sublicenses to the Patent and the Patent Rights without the
      requirement to pay any additional royalty fee or sublicense fee to Stock,
      to end users of the patented method including medical practitioners and
      medical clinics.

      The exclusive license granted herein also includes an exclusive right for
      the Licensee to grant sublicenses to the Patent and the Patent Rights to
      unaffiliated third parties other than the end users referred to
      hereinbefore. The Licensee acknowledges that such sublicenses shall not
      have the right to grant sub-sublicenses to the Patent and the Patent
      Rights unless consented to in writing by Stock; sub-sublicensing to
      end-users as defined in the paragraph above is, however, permitted without
      consent.

      Stock recognizes that by signing this Agreement, the combination of this
      Agreement and a patent license and royalty agreement between Brunner and
      Licensee will collectively constitute an EXCLUSIVE PATENT LICENSE AND
      ROYALTY AGREEMENT by which Stock and Brunner grant an exclusive license in
      the Patent to Licensee including the right to sue for past infringement.

3.    Representation by Stock. Stock warrants that he as the assignee of the
      right of Borberg, along with Brunner, as the joint inventors of United
      States Patent 6,245,038, exclusively owns and possesses the Patent and the
      Patent Rights, and has all right and title thereto and that this Patent
      License and Royalty Agreement is made without encumbrance or threat of
      future interference by others claiming ownership therein and that no
      security interests to any third party exists therein or any other
      agreement to the contrary.

4.    Representation by Licensee. Licensee represents that it is a bona fide
      corporation in good standing in Delaware.

5.    Advance Royalty Payments. Licensee agrees to pay Stock Fifty Thousand
      Dollars ($50,000 USD) annually as an advance and credited against any and
      all Royalty Payments paid in accordance with this Agreement. Such Advance
      Royalty Payments shall be non-refundable and be paid to Stock and in equal
      payments of Twelve Thousand Five-hundred Dollars ($12,500 USD), made
      quarterly, on or before the expiration of Forty-five (45) days after the
      reporting close of each prior calendar quarter.

6.    Royalty Payments. Licensee agrees to pay royalties to Stock totaling
      One-and-a-Half Percent (1.5% in USD). Royalty Payments shall be
      non-refundable and be calculated and paid based upon Total Net Revenues
      that Licensee, or any subsidiary of licensee or any company affiliated
      with licensee receives from the bona fide commercial sales of its Products
      sold in reliance and dependence upon the validity of the Patent's claims
      and of the Patent Rights in the Territory.

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7.    Sublicense Fee. In instances where Stock has consented to a sublicense to
      the Patent and the Patent Rights from Licensee to a third party who is not
      an end user of the patented method, Licensee agrees to pay to Stock a
      sublicense fee constituting a non-refundable cash payment equal to
      Twelve-and-a-Half Percent (12,5% in USD) of any:

            (i)   Upfront cash payment made to Licensee in consideration of the
                  sublicense;

            (ii)  Sublicense fees received by Licensee in consideration of the
                  sublicense;

            (iii) Premium over the fair market value of equity investments in
                  Licensee in consideration of the sublicense; and

            (iv)  Non-cash consideration received by Licensee from a sublicense
                  in consideration of the sublicense, such consideration to
                  include, without limitation, equity in other companies and the
                  value of any license granted to Licensee.

8.    Accounting and Timing of Royalty Payments and of payments of Sublicense
      Fees. Upon making each Royalty and Sublicense Fee Payment, Licensee shall
      provide Stock with a summary of the accounting used to determine the
      amount of Royalty Payment and Sublicense Fees due. Royalty Payments and
      Payments of Sublicense Fees shall be made by wire transfer and shall be
      computed on Total Net Revenues received by the Licensee by the reporting
      close of each calendar quarter and distributed and paid to Stock and on a
      quarterly basis, on or before the expiration of Forty-five (45) days
      after the reporting close of each prior calendar quarter.

9.    Failure to Pay by Licensee. Should Licensee fail to make any payments as
      required herein, and should the Licensee fail to cure the breach created
      thereby, any and all rights, title and ownership to the License provided
      to the Licensee under this Agreement shall be forfeited and any and all
      such rights, title and ownership to the License shall, upon notice of the
      failure to cure the breach, immediately revert to Stock, and all monies
      paid by Licensee until such date shall be retained by him without
      forfeiture.

10.   Territory. Shall mean the United States and any other jurisdictions
      subject to recognizing any valid claims of the Patent or of the Patent
      Rights.

11.   Total Net Revenues. Shall mean total gross revenues less any discounts,
      rebates, shipping costs, handling costs, transportation insurance costs,
      importation fees, and duties on any and all Products sold by the Licensee
      in the Territory which are sold in reliance upon and which are
      specifically used for extracorporeal therapies for the treatment of
      ophthalmic diseases in accordance with or subject to any of the valid
      claims of the Patent. In the case of sales of filters for ophthalmic
      treatment within the meaning of the Patent, either directly by Licensee or
      through Licensee's subsidiaries or a company affiliated with Licensee,
      such total gross revenues shall be deemed to be the cost of the filters to
      Licensee; or in case of Products having components in addition to said
      filters, the allocated cost of the filters to Licensee relative to the
      total costs of said Products. For

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      other Products the Total Net Revenues shall be the actual sales price to
      purchasers of the Products, less any of the discounts etc. as mentioned
      above.

12.   Records. Licensee agrees to keep complete and correct books, accounts and
      records according to Generally Accepted Accounting Principles (GAAP)
      regulations to facilitate computation of Royalty Payments and Sublicense
      Fees. Stock or his representatives acceptable to Licensee, shall have a
      full right of accounting including the right to confidentially examine
      Licensee's books and records, at all reasonable times and upon reasonable
      notice, for the purpose of verifying the amount of Royalty Payments due.
      In case of miscalculations elicited by such examination, Licensee shall
      compensate Stock for the agreed upon shortfall within thirty (30) days of
      receipt of a detailed report outlining the Royalty Payments determined to
      be due. In case the shortfall exceeds 5% or US$ 5.000, whichever is
      greater, Licensee shall reimburse Stock's costs for the examination.

13.   Products. Shall mean any filters, tubing sets or pumps sold by Licensee or
      its subsidiaries or affiliates to unaffiliated third parties in the
      Territory for the purposes of providing extracorporeal therapies for the
      treatment of the ophthalmic diseases as defined by any valid claim(s) of
      the Patent.

14.   Term and Termination. The Royalty Payments shall be due to Stock beginning
      with the first bona fide commercial sale of any Product in the Territory
      and may, at the discretion of Licensee terminate upon the first of any of
      the following three events to occur: (a) all patents of the Patent Rights
      expire; (b) all material patent claims of the Patent Rights are
      determined, in the opinion of an experienced patent attorney approved by
      Stock and Licensee or an independent experienced patent attorney selected
      by the American Arbitration Association in accordance with its rules if
      such joint approval cannot be obtained after thirty (30) days, to be
      invalid or unenforceable; or (c) a similarly fashioned competitive
      extracorporeal product, method or technology is commercially introduced in
      the Territory for use in ophthalmic indications that could not be deterred
      by best-efforts enforcement/infringement proceedings brought by Licensee
      against the competitive product, method or technology where such
      proceedings are made in reliance in full or in part upon the Patent's
      claims and or the Patent Rights.

      "material patent claims" within the meaning of this section of the
      Agreement are those claims of the Patent Rights covering a method for the
      effective therapeutic treatment of Age-related Macular Degeneration (AMD)
      using plasma differential separation techniques.

      Either Party may terminate this Agreement in the event of a material
      breach by the other Party that is not addressed elsewhere in this
      Agreement, provided only if the breaching Party is given Notice of the
      breach and a reasonable time, not to exceed thirty (30) days from the date
      of receipt of such Notice, in which to cure such breach. Stock may further
      terminate this Agreement in case of a final court order of bankruptcy or
      insolvency of Licensee, and in case Licensee refuses to defend and/or
      enforce the Patent (which defence or enforcement may include a license or
      other reasonable settlement) as provided under section 15. In the case of
      bankruptcy or insolvency of Stock the Licensee shall

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      retain its rights to the Patent and the Patent Rights in accordance with
      the terms of this agreement.

      The right of Stock to receive the royalty payments and Sublicense Fees
      under sections 5, 6 and 7 shall survive the death of Stock and shall
      become a receivable of Stock's estate until the termination of this
      agreement.

15.   Patent Defense. Licensee shall pay for any and all costs incurred for
      patent maintenance, enforcement and defense of the Patent or the Patent
      Rights in the Territory other than re-examination costs as noted below.
      Stock may, at his own expense, join with the Licensee in the enforcement
      or the defense of the Patent or the Patent Rights in the Territory. In
      case Licensee, after due consideration expressly indicates its refusal in
      writing to Stock to enforce or defend the Patent or the Patent Rights in
      the Territory then Stock may take his own steps to enforce or defend the
      Patent at his awn expense. Stock has no obligation for such participation,
      defense or enforcement at own expenses. Licensee may deduct the allocated
      costs for one reexamination procedure of US letters patent 6,245,038
      incurred under this section 14 from future Royalty Payments and Sublicense
      Fees payable to Stock under sections 6 and 7.

16.   Participation. Stock agrees, in consideration of the premises herein, that
      his executors and administrators will, at any time upon request,
      communicate to the Licensee, its successors and assigns, any facts
      relating to said Patent and Patent Rights, and the history thereof, known
      to him or his successors and assigns, and that he will testify as to the
      same in any interference or other proceeding when requested to do so by
      the Licensee, its successors and assigns. Any and all costs of such
      participation by Stock or his successors and assigns shall be borne by
      Licensee.

17.   Succession. Stock binds himself and his heirs, executors, administrators,
      employees and legal representatives, as the case may be, to execute and
      deliver to the Licensee, any further documents or instruments and to do
      any and all further acts that may be deemed necessary by the Licensee (i)
      in connection with any aspect of the re-examination proceedings, (ii) in
      connection with any proceedings to enforce or defend the Patent; (iii) to
      file applications for improvements and inventions in any country where
      Licensee may elect to file such application(s), and (iv) that may be
      necessary to vest in the Licensee, the license, rights or title herein
      conveyed, or intended so to be, and to enable such title to be recorded in
      the United States and or foreign countries where such application(s) may
      be filed. Any and all costs of such participation by Stock or his
      successors and assigns shall be borne by Licensee.

18.   Relationship of the Parties; Indemnification. It is agreed that this
      Agreement does not make any Party herein a general or special agent, legal
      representative, subsidiary, joint venturer, partner, employee or servant
      of any other Party herein for any purpose.

19.   Validity. During the time of this agreement, licensee will not challenge
      the validity of the patent rights at court or with patent authorities, or
      will support third parties in such a challenge. The parties acknowledge
      that the re-examination proceedings shall not be considered a challenge of
      the Patent Rights.

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20.   Breach and Disputes. Any breaching Party shall have Thirty (30) Days from
      the date of notification to cure such breach. Any dispute between the
      Parties to this Agreement shall be resolved through binding arbitration,
      which shall be governed under the rules and regulations of the American
      Arbitration Association.

21.   Forum, Venue and Governing Law. This agreement shall be governed and
      interpreted under Delaware law (without applying its conflict of law
      principles). Exclusive venue for legal proceedings arising hereunder shall
      be in New York, New York.

22.   Entire Agreement. This Agreement supersedes any prior understanding that
      may have been reached between the Parties (including the Consulting
      Agreement between OccuLogix Corporation and Hans Stock dated June 25,
      2002) and encompasses the entire agreement between the Licensee and Stock
      with respect to the Patent and the Patent Rights. The terms of this
      Agreement are confidential and shall be maintained by the Parties in
      accordance thereby.

23.   Modification. This Agreement cannot be modified except in writing executed
      mutually between the Parties.

24.   Assignment Licensee shall not grant, transfer, convey or otherwise assign
      any of its rights under this Agreement without the express consent in
      writing of Stock.

            IN WITNESS WHEREOF, the Parties have signed and executed this
Agreement and have caused this Agreement to become effective as of the Effective
Date last executed below.

OCCULOGIX, INC.                            HANS STOCK

By: /s/ Elias Vamvakas                     /s/ Hans Stock
    ------------------------------         -------------------------------------

Title: ___________________________

Date: Oct 25, 2004                         Date: October 25, 2004