Document:

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                                                                     EXHIBIT 4.2

                          REGISTRATION RIGHTS AGREEMENT

               THIS REGISTRATION RIGHTS AGREEMENT is made and entered into as of
November 1, 2000 by and between Allergan, Inc., a Delaware corporation ("the
Company"), and Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
Incorporated, (the "Purchaser") pursuant to the Purchase Agreement, dated as of
October 26, 2000 (the "Purchase Agreement"), between the Company and the
Purchaser. In order to induce the Purchaser to enter into the Purchase
Agreement, the Company has agreed to provide the registration rights set forth
in this Agreement. The execution of this Agreement is a condition to the closing
under the Purchase Agreement.

               The Company agrees with the Purchaser, (i) for its benefit as
Purchaser and (ii) for the benefit of the beneficial owners (including the
Purchaser) from time to time of the LYONs (as defined herein) and the beneficial
owners from time to time of the Underlying Common Stock (as defined herein)
issued upon conversion of the LYONs (each of the foregoing a "Holder" and
together the "Holders"), as follows:

               Section 1. Definitions. Capitalized terms used herein without
definition shall have their respective meanings set forth in the Purchase
Agreement. As used in this Agreement, the following terms shall have the
following meanings:

               Affiliate: With respect to any specified person, an "affiliate,"
as defined in Rule 144, of such person.

               Amendment Effectiveness Deadline Date: See Section 2(d) hereof.

               Applicable Conversion Price: The Applicable Conversion Price as
of any date of determination means the Applicable Principal Amount per $1,000
principal amount at maturity of LYONs as of such date of determination divided
by the Conversion Rate in effect as of such date of determination or, if no
LYONs are then outstanding, the Conversion Rate that would be in effect were
LYONs then outstanding.

               Applicable Principal Amount: Applicable Principal Amount as of
any date of determination, with respect to each $1,000 principal amount at
maturity of LYONs means the sum of the initial issue price of such LYONs
($608.41) plus accrued original issue discount with respect to such LYON through
such date of determination or, if no LYONs are then outstanding, such sum
calculated as if such LYONs were then outstanding.

               Business Day: Each Monday, Tuesday, Wednesday, Thursday and
Friday that is not a day on which banking institutions in The City of New York
are authorized or obligated by law or executive order to close.

               Common Stock: The shares of Common Stock, $0.01 par value, of the
Company and any other shares of common stock as may constitute "Common Stock"
for purposes of the Indenture, including the Underlying Common Stock.

               Conversion Rate: Conversion Rate shall have the meaning assigned
such term in the Indenture.

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               Damages Accrual Period: See Section 2(e) hereof.

               Damages Payment Date: Each [Month/Day] and [Month/Day] in the
case of LYONs and the Underlying Common Stock.

               Deferral Notice: See Section 3(i) hereof.

               Deferral Period:  See Section 3(i) hereof.

               Effectiveness Deadline Date:  See Section 2(a) hereof.

               Effectiveness Period: The period of (i) two years from the later
of the (a) Issue Date or (b) the last date of original issuance of the LYONs or
(ii) such shorter period ending on the date that all Registrable Securities have
ceased to be Registrable Securities.

               Event:  See Section 2(e) hereof.

               Event Termination Date:  See Section 2(e) hereof.

               Event Date:  See Section 2(e) hereof.

               Exchange Act: The Securities Exchange Act of 1934, as amended,
and the rules and regulations of the SEC promulgated thereunder.

               Filing Deadline Date:  See Section 2(a) hereof.

               Holder:  See the second paragraph of this Agreement.

               Indenture: The Indenture dated as of the date hereof between the
Company and U.S. Bank Trust National Association, as trustee, pursuant to which
the LYONs are being issued.

               Initial Shelf Registration Statement:  See Section 2(a) hereof.

               Issue Date:  November 1, 2000.

               Liquidated Damages Amount:  See Section 2(e) hereof.

               Losses:  See Section 6 hereof.

               LYONs: The Liquid Yield Option Notes due 2020 of the Company to
be purchased pursuant to the Purchase Agreement.

               Material Event:  See Section 3(i) hereof.

               Notice and Questionnaire: A written notice delivered to the
Company containing substantially the information called for by the Selling
Security Holder Notice and Questionnaire attached as Annex A to the Offering
Memorandum of the Company issued October 26, 2000 relating to the LYONs.

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               Notice Holder: On any date, any Holder that has delivered a
Notice and Questionnaire to the Company on or prior to such date.

               Prospectus: The prospectus included in any Registration Statement
(including, without limitation, a prospectus that discloses information
previously omitted from a prospectus filed as part of an effective registration
statement in reliance upon Rule 430A promulgated under the Securities Act), as
amended or supplemented by any amendment or prospectus supplement, including
post-effective amendments, and all materials incorporated by reference or
explicitly deemed to be incorporated by reference in such Prospectus.

               Purchase Agreement:  See the first paragraph of this Agreement.

               Purchaser: Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner &
Smith Incorporated.

               Record Holder: With respect to any Damages Payment Date relating
to any LYON or Underlying Common Stock as to which any Liquidated Damages Amount
has accrued, the registered holder of such LYON or Underlying Common Stock, as
the case may be, 15 days prior to the next succeeding Damages Payment Date.

               Registrable Securities: The LYONs and the Underlying Common
Stock, until such securities have been converted or exchanged, and, at all times
subsequent to any such conversion or exchange, any securities into or for which
such securities have been converted or exchanged, and any security issued with
respect thereto upon any stock dividend, split or similar event until, in the
case of any such security, the earliest of (i) its effective registration under
the Securities Act and resale in accordance with the Registration Statement
covering it, (ii) expiration of the holding period that would be applicable
thereto under Rule 144(k) were it not held by an Affiliate of the Company or
(iii) its sale to the public pursuant to Rule 144.

               Registration Expenses:  See Section 5 hereof.

               Registration Statement: Any registration statement of the Company
that covers any of the Registrable Securities pursuant to the provisions of this
Agreement, including the Prospectus, amendments and supplements to such
registration statement, including post-effective amendments, all exhibits, and
all materials incorporated by reference or explicitly deemed to be incorporated
by reference in such registration statement.

               Restricted Securities:  As this term is defined in Rule 144.

               Rule 144: Rule 144 under the Securities Act, as such Rule may be
amended from time to time, or any similar rule or regulation hereafter adopted
by the SEC.

               Rule 144A: Rule 144A under the Securities Act, as such Rule may
be amended from time to time, or any similar rule or regulation hereafter
adopted by the SEC.

               SEC:  The Securities and Exchange Commission.

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               Securities Act: The Securities Act of 1933, as amended, and the
rules and regulations promulgated by the SEC thereunder.

               Shelf Registration Statement:  See Section 2(a) hereof.

               Subsequent Shelf Registration Statement: See Section 2(b) hereof.

               TIA:  The Trust Indenture Act of 1939, as amended.

               Trustee: U.S. Bank Trust National Association (or any successor
entity), the Trustee under the Indenture.

               Underlying Common Stock: The Common Stock into which the LYONs
are convertible or issued upon any such conversion.

Section 2.     Shelf Registration

               (a) The Company shall prepare and file or cause to be prepared
and filed with the SEC, as soon as practicable but in any event by the date (the
"Filing Deadline Date") ninety (90) days after the Issue Date, a Registration
Statement for an offering to be made on a delayed or continuous basis pursuant
to Rule 415 of the Securities Act (a "Shelf Registration Statement") registering
the resale from time to time by Holders thereof of all of the Registrable
Securities (the "Initial Shelf Registration Statement"). The Initial Shelf
Registration Statement shall be on Form S-3 or another appropriate form
permitting registration of such Registrable Securities for resale by such
Holders in accordance with the methods of distribution elected by the Holders
and set forth in the Initial Shelf Registration Statement. The Company shall use
reasonable efforts to cause the Initial Shelf Registration Statement to be
declared effective under the Securities Act as promptly as is practicable but in
any event by the date (the "Effectiveness Deadline Date") that is one hundred
and eighty (180) days after the Issue Date, and to keep the Initial Shelf
Registration Statement (or any Subsequent Shelf Registration Statement)
continuously effective under the Securities Act until the expiration of the
Effectiveness Period. At the time the Initial Shelf Registration Statement is
declared effective, each Holder that became a Notice Holder on or prior to the
date ten (10) Business Days prior to such time of effectiveness shall be named
as a selling security holder in the Initial Shelf Registration Statement and the
related Prospectus in such a manner as to permit such Holder to deliver such
Prospectus to purchasers of Registrable Securities in accordance with applicable
law. None of the Company's security holders (other than the Holders of
Registrable Securities) shall have the right to include any of the Company's
securities in the Shelf Registration Statement.

               (b) If the Initial Shelf Registration Statement or any Subsequent
Shelf Registration Statement ceases to be effective for any reason at any time
during the Effectiveness Period (other than because all Registrable Securities
registered thereunder shall have been resold pursuant thereto or shall have
otherwise ceased to be Registrable Securities), the Company shall use all
reasonable efforts to obtain the prompt withdrawal of any order suspending the
effectiveness thereof, and in any event shall within thirty (30) days of such
cessation of effectiveness amend the Shelf Registration Statement in a manner
reasonably expected to obtain the withdrawal of the order suspending the
effectiveness thereof, or file an additional Shelf Registration Statement
covering all of the securities that as of the date of such filing are

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Registrable Securities (a "Subsequent Shelf Registration Statement"). If a
Subsequent Shelf Registration Statement is filed, the Company shall use all
reasonable efforts to cause the Subsequent Shelf Registration Statement to
become effective as promptly as is practicable after such filing and to keep
such Registration Statement (or subsequent Shelf Registration Statement)
continuously effective until the end of the Effectiveness Period.

               (c) The Company shall supplement and amend the Shelf Registration
Statement if required by the rules, regulations or instructions applicable to
the registration form used by the Company for such Shelf Registration Statement,
if required by the Securities Act or, to the extent to which the Company does
not reasonably object, as reasonably requested by the Purchaser or by the
Trustee on behalf of the registered Holders.

               (d) Each Holder of Registrable Securities agrees that if such
Holder wishes to sell Registrable Securities pursuant to a Shelf Registration
Statement and related Prospectus, it will do so only in accordance with this
Section 2(d) and Section 3(i). Each Holder of Registrable Securities wishing to
sell Registrable Securities pursuant to a Shelf Registration Statement and
related Prospectus agrees to deliver a Notice and Questionnaire to the Company
at least five (5) Business Days prior to any intended distribution of
Registrable Securities under the Shelf Registration Statement. From and after
the date the Initial Shelf Registration Statement is declared effective, the
Company shall, as promptly as is practicable after the date a Notice and
Questionnaire is delivered, and in any event within five (5) Business Days after
such date, (i) if required by applicable law, file with the SEC a post-effective
amendment to the Shelf Registration Statement or prepare and, if required by
applicable law, file a supplement to the related Prospectus or a supplement or
amendment to any document incorporated therein by reference or file any other
required document so that the Holder delivering such Notice and Questionnaire is
named as a selling security holder in the Shelf Registration Statement and the
related Prospectus in such a manner as to permit such Holder to deliver such
Prospectus to purchasers of the Registrable Securities in accordance with
applicable law and, if the Company shall file a post-effective amendment to the
Shelf Registration Statement, use reasonable efforts to cause such
post-effective amendment to be declared effective under the Securities Act as
promptly as is practicable, but in any event by the date (the "Amendment
Effectiveness Deadline Date") that is forty-five (45) days after the date such
post-effective amendment is required by this clause to be filed; (ii) provide
such Holder copies of any documents filed pursuant to Section 2(d)(i); and (iii)
notify such Holder as promptly as practicable after the effectiveness under the
Securities Act of any post-effective amendment filed pursuant to Section
2(d)(i); provided, that if such Notice and Questionnaire is delivered during a
Deferral Period, the Company shall so inform the Holder delivering such Notice
and Questionnaire and shall take the actions set forth in clauses (i), (ii) and
(iii) of this Section 2(d) upon expiration of the Deferral Period in accordance
with Section 3(i), provided, further, that if under applicable law the Company
has more than one option as to the type or manner of making any such filing, it
will make the required filing or filings in the manner or of a type that is
reasonably expected to result in the earliest availability of the Prospectus for
effecting resales of Registrable Securities. Notwithstanding anything contained
herein to the contrary, the Company shall be under no obligation to name any
Holder that is not a Notice Holder as a selling security holder in any
Registration Statement or related Prospectus; provided, however, that any Holder
that becomes a Notice Holder pursuant to the provisions of Section 2(d) of this
Agreement (whether or not such Holder was a Notice Holder at the time the
Registration Statement was declared effective) shall be named as a selling
security

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holder in the Registration Statement or related Prospectus in accordance with
the requirements of this Section 2(d).

               (e) The parties hereto agree that the Holders of Registrable
Securities will suffer damages, and that it would not be feasible to ascertain
the extent of such damages with precision, if (i) the Initial Shelf Registration
Statement has not been filed on or prior to the Filing Deadline Date, (ii) the
Initial Shelf Registration Statement has not been declared effective under the
Securities Act on or prior to the Effectiveness Deadline Date, (iii) the Company
has failed to perform its obligations set forth in Section 2(d) within the time
period required therein, (iv) the aggregate duration of Deferral Periods in any
period exceeds the number of days permitted in respect of such period pursuant
to Section 3(i) or (v) the number of Deferral Periods in any period exceeds the
number permitted in respect of such period pursuant to Section 3(i) (each of the
events of a type described in any clauses (i) through (v) of this Section 3(d)
are individually referred to herein as an "Event," and the Filing Deadline Date
in the case of clause (i) of this Section 3(d), the Effectiveness Deadline Date
in the case of clause (ii) of this Section 3(d), the date by which the Company
is required to perform its obligations set forth in Section 2(d) in the case of
clause (iii) of this Section 3(d) (including the filing of any post-effective
amendment prior to the Amendment Effectiveness Deadline Date), the date on which
the aggregate duration of Deferral Periods in any period exceeds the number of
days permitted by Section 3(i) hereof in the case of clause (iv) of this Section
3(d), and the date of the commencement of a Deferral Period that causes the
limit on the number of Deferral Periods in any period under Section 3(i) hereof
to be exceeded in the case of clause (v) of this Section 3(d), being referred to
herein as an "Event Date"). Events shall be deemed to continue until the "Event
Termination Date," which shall be the following dates with respect to the
respective types of Events: the date the Initial Shelf Registration Statement is
filed in the case of an Event of the type described in clause (i) of this
Section 3(d), the date the Initial Shelf Registration Statement is declared
effective under the Securities Act in the case of an Event of the type described
in clause (ii) of this Section 3(d), the date the Company performs its
obligations set forth in Section 2(d) in the case of an Event of the type
described in clause (iii) of this Section 3(d) (including, without limitation,
the date the relevant post-effective amendment to the Shelf Registration
Statement is declared effective under the Securities Act), termination of the
Deferral Period that caused the limit on the aggregate duration of Deferral
Periods in a period set forth in Section 3(i) to be exceeded in the case of the
commencement of an Event of the type described in clause (iv) of this Section
3(d), and termination of the Deferral Period the commencement of which caused
the number of Deferral Periods in a period permitted by Section 3(i) to be
exceeded in the case of an Event of the type described in clause (v) of this
Section 3(d).

               Accordingly, commencing on (and including) any Event Date and
ending on (but excluding) the next date on which there are no Events that have
occurred and are continuing (a "Damages Accrual Period"), the Company agrees to
pay, as liquidated damages and not as a penalty, an amount (the "Liquidated
Damages Amount"), payable on the Damages Payment Dates to Record Holders of then
outstanding LYONs that are Registrable Securities and of then outstanding shares
of Underlying Common Stock issued upon conversion of LYONs that are Registrable
Securities, as the case may be, accruing, for each portion of such Damages
Accrual Period beginning on and including a Damages Payment Date (or, in respect
of the first time that the Liquidation Damages Amount is to be paid to Holders
on a Damages Payment Date as a result of the occurrence of any particular Event,
from the Event Date) and ending on but

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excluding the first to occur of (A) the date of the end of the Damages Accrual
Period or (B) the Next Damages Payment Date, at a rate per annum equal to
one-quarter of one percent (0.25%) for the first 90-day period from the Event
Date, and thereafter at a rate per annum equal to one-half of one percent (0.5%)
of the aggregate Applicable Principal Amount of such LYONs and the aggregate
Applicable Conversion Price of such shares of Underlying Common Stock, as the
case may be, in each case determined as of the Business Day immediately
preceding the next Damages Payment Date; provided, that in the case of a Damages
Accrual Period that is in effect solely as a result of an Event of the type
described in clause (iii) of the immediately preceding paragraph, such
Liquidated Damages Amount shall be paid only to the Holders that have delivered
Notice and Questionnaires that caused the Company to incur the obligations set
forth in Section 2(d) the non-performance of which is the basis of such Event;
provided further, that any Liquidated Damages Amount accrued with respect to any
LYON or portion thereof called for redemption on a redemption date or converted
into Underlying Common Stock on a conversion date prior to the Damages Payment
Date, shall, in any such event, be paid instead to the Holder who submitted such
LYON or portion thereof for redemption or conversion on the applicable
redemption date or conversion date, as the case may be, on such date (or
promptly following the conversion date, in the case of conversion).
Notwithstanding the foregoing, no Liquidated Damages Amounts shall accrue as to
any Registrable Security from and after the earlier of (x) the date such
security is no longer a Registrable Security and (y) expiration of the
Effectiveness Period. The rate of accrual of the Liquidated Damages Amount with
respect to any period shall not exceed the rate provided for in this paragraph
notwithstanding the occurrence of multiple concurrent Events. Following the cure
of all Events requiring the payment by the Company of Liquidated Damages Amounts
to the Holders of Registrable Securities pursuant to this Section, the accrual
of Liquidated Damages Amounts will cease (without in any way limiting the effect
of any subsequent Event requiring the payment of Liquidated Damages Amount by
the Company).

               The Trustee shall be entitled, on behalf of Holders of LYONs or
Underlying Common Stock, to seek any available remedy for the enforcement of
this Agreement, including for the payment of any Liquidated Damages Amount.
Notwithstanding the foregoing, the parties agree that the sole monetary damages
payable for a violation of the terms of this Agreement with respect to which
liquidated damages are expressly provided shall be such liquidated damages.
Nothing shall preclude a Notice Holder or Holder of Registrable Securities from
pursuing or obtaining specific performance or other equitable relief with
respect to this Agreement.

               All of the Company's obligations set forth in this Section 2(e)
that are outstanding with respect to any Registrable Security at the time such
security ceases to be a Registrable Security shall survive until such time as
all such obligations with respect to such security have been satisfied in full
(notwithstanding termination of this Agreement pursuant to Section 8(k)).

               The parties hereto agree that the liquidated damages provided for
in this Section 2(e) constitute a reasonable estimate of the damages that may be
incurred by Holders of Registrable Securities by reason of the failure of the
Shelf Registration Statement to be filed or declared effective or available for
effecting resales of Registrable Securities in accordance with the provisions
hereof.

               Section 3. Registration Procedures. In connection with the
registration obligations of the Company under Section 2 hereof, the Company
shall:

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               (a) Before filing any Registration Statement or Prospectus or any
amendments or supplements thereto with the SEC, furnish to the Purchaser copies
of all such documents proposed to be filed and use reasonable efforts to reflect
in each such document when so filed with the SEC such comments as the Purchaser
reasonably shall propose within three (3) Business Days of the delivery of such
copies to the Purchaser.

               (b) (i) Prepare and file with the SEC such amendments and
post-effective amendments to each Registration Statement as may be necessary to
keep such Registration Statement continuously effective for the applicable
period specified in Section 2(a); (ii) cause the related Prospectus to be
supplemented by any required Prospectus supplement, and as so supplemented to be
filed pursuant to Rule 424 (or any similar provisions then in force) under the
Securities Act; and (iii) use all reasonable efforts to comply with the
provisions of the Securities Act applicable to it with respect to the
disposition of all securities covered by such Registration Statement during the
Effectiveness Period in accordance with the intended methods of disposition by
the sellers thereof set forth in such Registration Statement as so amended or
such Prospectus as so supplemented.

               (c) As promptly as practicable give notice to the Notice Holders
and the Purchaser (i) when any Prospectus, Prospectus supplement, Registration
Statement or post-effective amendment to a Registration Statement has been filed
with the SEC and, with respect to a Registration Statement or any post-effective
amendment, when the same has been declared effective, (ii) of any request,
following the effectiveness of the Initial Shelf Registration Statement under
the Securities Act, by the SEC or any other federal or state governmental
authority for amendments or supplements to any Registration Statement or related
Prospectus or for additional information, (iii) of the issuance by the SEC or
any other federal or state governmental authority of any stop order suspending
the effectiveness of any Registration Statement or the initiation or threatening
of any proceedings for that purpose, (iv) of the receipt by the Company of any
notification with respect to the suspension of the qualification or exemption
from qualification of any of the Registrable Securities for sale in any
jurisdiction or the initiation or threatening of any proceeding for such
purpose, (v) of the occurrence of (but not the nature of or details concerning)
a Material Event (provided, however, that no notice by the Company shall be
required pursuant to this clause (v) in the event that the Company either
promptly files a Prospectus supplement to update the Prospectus or a Form 8-K or
other appropriate Exchange Act report that is incorporated by reference into the
Registration Statement, which, in either case, contains the requisite
information with respect to such Material Event that results in such
Registration Statement no longer containing any untrue statement of material
fact or omitting to state a material fact necessary to make the statements
contained therein not misleading) and (vi) of the determination by the Company
that a post-effective amendment to a Registration Statement will be filed with
the SEC, which notice may, at the discretion of the Company (or as required
pursuant to Section 3(i)), state that it constitutes a Deferral Notice, in which
event the provisions of Section 3(i) shall apply.

               (d) Use all reasonable efforts to obtain the withdrawal of any
order suspending the effectiveness of a Registration Statement or the lifting of
any suspension of the qualification (or exemption from qualification) of any of
the Registrable Securities for sale in any jurisdiction in which they have been
qualified for sale, in either case at the earliest possible moment.

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               (e) If reasonably requested by the Purchaser or any Notice
Holder, promptly as reasonably practicable incorporate in a Prospectus
supplement or post-effective amendment to a Registration Statement such
information as the Purchaser or such Notice Holder shall, on the basis of an
opinion of nationally-recognized counsel experienced in such matters, determine
to be required to be included therein by applicable law and make any required
filings of such Prospectus supplement or such post-effective amendment;
provided, that the Company shall not be required to take any actions under this
Section 3(e) that are not, in the reasonable opinion of counsel for the Company,
in compliance with applicable law.

               (f) Promptly as reasonably practicable furnish to each Notice
Holder and the Purchaser, upon their request and without charge, at least one
(1) conformed copy of the Registration Statement and any amendment thereto,
including financial statements but excluding schedules, all documents
incorporated or deemed to be incorporated therein by reference and all exhibits
(unless requested in writing to the Company by such Notice Holder or the
Purchaser, as the case may be).

               (g) During the Effectiveness Period, deliver to each Notice
Holder in connection with any sale of Registrable Securities pursuant to a
Registration Statement, without charge, as many copies of the Prospectus or
Prospectuses relating to such Registrable Securities (including each preliminary
prospectus) and any amendment or supplement thereto as such Notice Holder may
reasonably request; and the Company hereby consents (except during such periods
that a Deferral Notice is outstanding and has not been revoked) to the use of
such Prospectus or each amendment or supplement thereto by each Notice Holder in
connection with any offering and sale of the Registrable Securities covered by
such Prospectus or any amendment or supplement thereto in the manner set forth
therein.

               (h) Prior to any public offering of the Registrable Securities
pursuant to the Shelf Registration Statement, use all reasonable efforts to
register or qualify or cooperate with the Notice Holders in connection with the
registration or qualification (or exemption from such registration or
qualification) of such Registrable Securities for offer and sale under the
securities or Blue Sky laws of such jurisdictions within the United States as
any Notice Holder reasonably requests in writing (which request may be included
in the Notice and Questionnaire); prior to any public offering of the
Registrable Securities pursuant to the Shelf Registration Statement, use all
reasonable efforts to keep each such registration or qualification (or exemption
therefrom) effective during the Effectiveness Period in connection with such
Notice Holder's offer and sale of Registrable Securities pursuant to such
registration or qualification (or exemption therefrom) and do any and all other
acts or things necessary or advisable to enable the disposition in such
jurisdictions of such Registrable Securities in the manner set forth in the
relevant Registration Statement and the related Prospectus; provided, that the
Company will not be required to (i) qualify as a foreign corporation or as a
dealer in securities in any jurisdiction where it would not otherwise be
required to qualify but for this Agreement or (ii) take any action that would
subject it to general service of process in suits or to taxation in any such
jurisdiction where it is not then so subject.

               (i) Upon (A) the issuance by the SEC of a stop order suspending
the effectiveness of the Shelf Registration Statement or the initiation of
proceedings with respect to the Shelf Registration Statement under Section 8(d)
or 8(e) of the Securities Act, (B) the

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occurrence of any event or the existence of any fact (a "Material Event") as a
result of which any Registration Statement shall contain any untrue statement of
a material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein not misleading, or any Prospectus
shall contain any untrue statement of a material fact or omit to state any
material fact required to be stated therein or necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading, or (C) the occurrence or existence of any pending corporate
development that, in the discretion of the Company, makes it appropriate to
suspend the availability of the Shelf Registration Statement and the related
Prospectus, (i) in the case of clause (B) of this Section 3(i), subject to the
next sentence, as promptly as practicable prepare and file a post-effective
amendment to such Registration Statement or a supplement to the related
Prospectus or any document incorporated therein by reference or file any other
required document that would be incorporated by reference into such Registration
Statement and Prospectus so that such Registration Statement does not contain
any untrue statement of a material fact or omit to state any material fact
required to be stated therein or necessary to make the statements therein not
misleading, and such Prospectus does not contain any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading, as thereafter delivered to the
purchasers of the Registrable Securities being sold thereunder, and, in the case
of a post-effective amendment to a Registration Statement, subject to the next
sentence, use all reasonable efforts to cause it to be declared effective as
promptly as is reasonably practicable, and (ii) give notice to the Notice
Holders that the availability of the Shelf Registration Statement is suspended
(a "Deferral Notice") and, upon receipt of any Deferral Notice, each Notice
Holder agrees not to sell any Registrable Securities pursuant to the
Registration Statement until such Notice Holder's receipt of copies of the
supplemented or amended Prospectus provided for in clause (i) above, or until it
is advised in writing by the Company that the Prospectus may be used, and has
received copies of any additional or supplemental filings that are incorporated
or deemed incorporated by reference in such Prospectus. The Company will all use
reasonable efforts to ensure that the use of the Prospectus may be resumed (x)
in the case of clause (A) above, as promptly as is practicable, (y) in the case
of clause (B) above, as soon as, in the sole judgment of the Company, public
disclosure of such Material Event would not be prejudicial to or contrary to the
interests of the Company or, if necessary to avoid unreasonable burden or
expense, as soon as reasonably practicable thereafter and (z) in the case of
clause (C) above, as soon as, in the discretion of the Company, such suspension
is no longer appropriate. The period during which the availability of the
Registration Statement and any Prospectus is suspended (the "Deferral Period")
shall, without the Company incurring any obligation to pay liquidated damages
pursuant to Section 2(e), not exceed forty-five (45) days in any three (3) month
period or ninety (90) days in any twelve (12) month period.

               (j) If reasonably requested in writing in connection with a
disposition of Registrable Securities pursuant to a Registration Statement in
connection with an underwritten offering, make reasonably available for
inspection during normal business hours by one representative for the Notice
Holders of such Registrable Securities to be registered thereunder and any
broker-dealers, attorneys and accountants retained by such Notice Holders, all
relevant financial and other records, pertinent corporate documents and
properties of the Company and its subsidiaries, and cause the appropriate
executive officers, directors and designated employees of the Company and its
subsidiaries to make reasonably available for inspection during normal

                                       10
<PAGE>   11
business hours all relevant information reasonably requested by such
representative for the Notice Holders or any such broker-dealers, attorneys or
accountants in connection with such disposition, in each case as is customary
for similar "due diligence" examinations; provided, however, that such persons
shall first agree in writing with the Company that any information that is
reasonably and in good faith designated by the Company in writing as
confidential at the time of delivery of such information shall be kept
confidential by such persons and shall be used solely for the purposes of
exercising rights under this Agreement, unless (i) disclosure of such
information is required by court or administrative order or is necessary to
respond to inquiries of regulatory authorities, (ii) disclosure of such
information is required by law (including any disclosure requirements pursuant
to federal securities laws in connection with the filing of any Registration
Statement or the use of any Prospectus referred to in this Agreement), (iii)
such information becomes generally available to the public other than as a
result of a disclosure or failure to safeguard by any such person or (iv) such
information becomes available to any such person from a source other than the
Company and such source is not bound by a confidentiality agreement; and
provided further, that the foregoing inspection and information gathering shall,
to the greatest extent possible, be coordinated on behalf of all the Notice
Holders and the other parties entitled thereto by the counsel referred to in
Section 5.

               (k) Comply with all applicable rules and regulations of the SEC
and make generally available to its securityholders earning statements (which
need not be audited) satisfying the provisions of Section 11(a) of the
Securities Act and Rule 158 thereunder (or any similar rule promulgated under
the Securities Act) no later than 45 days after the end of any 12-month period
(or 90 days after the end of any 12-month period if such period is a fiscal
year) commencing on the first day of the first fiscal quarter of the Company
commencing after the effective date of a Registration Statement, which
statements shall cover said 12-month periods.

               (l) Cooperate with each Notice Holder to facilitate the timely
preparation and delivery of certificates representing Registrable Securities
sold pursuant to a Registration Statement, and cause such Registrable Securities
to be in such denominations as are permitted by the Indenture and registered in
such names as such Notice Holder may request in writing at least two Business
Days prior to any sale of such Registrable Securities.

               (m) Provide a CUSIP number for all Registrable Securities covered
by each Registration Statement not later than the effective date of such
Registration Statement and provide the Trustee for the LYONs and the transfer
agent for the Common Stock with printed certificates for the Registrable
Securities that are in a form eligible for deposit with The Depository Trust
Company.

               (n) Make a reasonable effort to provide such information as is
required for any filings required to be made with the National Association of
Securities Dealers, Inc.

               (o) Upon (i) the filing of the Initial Shelf Registration
Statement and (ii) the effectiveness of the Initial Shelf Registration
Statement, announce the same, in each case by release to Reuters Economic
Services and Bloomberg Business News.

               (p) Enter into such customary agreements and take all such other
reasonable necessary actions in connection therewith (including those reasonably
requested by the holders

                                       11
<PAGE>   12

of a majority of the Registrable Securities being sold) in order to expedite or
facilitate disposition of such Registrable Securities; and

               (q) Cause the Indenture to be qualified under the TIA not later
than the effective date of any Registration Statement; and in connection
therewith, cooperate with the Trustee to effect such changes to the Indenture as
may be required for the Indenture to be so qualified in accordance with the
terms of the TIA and execute, and use all reasonable efforts to cause the
Trustee to execute, all documents as may be required to effect such changes, and
all other forms and documents required to be filed with the SEC to enable the
Indenture to be so qualified in a timely manner.

               Section 4. Holder's Obligations. Each Holder agrees, by
acquisition of the Registrable Securities, that no Holder of Registrable
Securities shall be entitled to sell any of such Registrable Securities pursuant
to a Registration Statement or to receive a Prospectus relating thereto, unless
such Holder has furnished the Company with a Notice and Questionnaire as
required pursuant to Section 2(d) (including the information required to be
included in such Notice and Questionnaire) and the information set forth in the
next sentence. Each Notice Holder agrees promptly to furnish to the Company all
information required to be disclosed in order to make the information previously
furnished to the Company by such Notice Holder not misleading and any other
information regarding such Notice Holder and the distribution of such
Registrable Securities as may be required to be disclosed in the Registration
Statement under applicable law.

               Section 5. Registration Expenses. The Company shall bear all
reasonable fees and expenses incurred in connection with the performance by the
Company of its obligations under Sections 2 and 3 of this Agreement whether or
not any of the Registration Statements are declared effective. Such fees and
expenses shall include, without limitation, (i) all registration and filing fees
(including, without limitation, fees and expenses (x) with respect to filings
required to be made with the National Association of Securities Dealers, Inc.
and (y) of compliance with federal and state securities or Blue Sky laws
(including, without limitation, reasonable fees and disbursements of the counsel
specified in the next sentence in connection with Blue Sky qualifications of the
Registrable Securities under the laws of such jurisdictions as the Notice
Holders of a majority of the Registrable Securities being sold pursuant to a
Registration Statement may designate), (ii) printing expenses (including,
without limitation, expenses of printing certificates for Registrable Securities
in a form eligible for deposit with The Depository Trust Company), (iii)
duplication expenses relating to copies of any Registration Statement or
Prospectus delivered to any Holders hereunder, (iv) fees and disbursements of
counsel for the Company in connection with the Shelf Registration Statement, and
(v) reasonable fees and disbursements of the Trustee and its counsel and of the
registrar and transfer agent for the Common Stock. In addition, the Company
shall bear or reimburse the Notice Holders for the reasonable fees and
disbursements of one firm of legal counsel for the Holders, which shall
initially be Shearman & Sterling, but which may, upon the written consent of the
Purchaser (which shall not be unreasonably withheld), be another nationally
recognized law firm experienced in securities law matters designated by the
Company. In addition, the Company shall pay the internal expenses of the Company
(including, without limitation, all salaries and expenses of officers and
employees performing legal or accounting duties), the expense of any annual
audit, the fees and expenses incurred in connection with the listing of the
Registrable

                                       12
<PAGE>   13

Securities on any securities exchange on which similar securities of the Company
are then listed and the fees and expenses of any person, including special
experts, retained by the Company.

               Indemnification; Contribution.(a) The Company agrees to indemnify
and hold harmless the Purchaser and each holder of Registrable Securities and
each person, if any, who controls the Purchaser or any holder of Registrable
Securities within the meaning of either Section 15 of the Securities Act or
Section 20 of the Exchange Act, as follows:

               (i) against any and all loss, liability, claim, damage and
        expense whatsoever, as incurred, arising out of any untrue statement or
        alleged untrue statement of a material fact contained in the
        Registration Statement (or any amendment thereto), or the omission or
        alleged omission therefrom of a material fact necessary in order to make
        the statements therein, in light of the circumstances under which they
        were made, not misleading or arising out of any untrue statement or
        alleged untrue statement of a material fact included in any preliminary
        prospectus or the Prospectus (or any amendment or supplement thereto),
        or the omission or alleged omission therefrom of a material fact
        necessary in order to make the statements therein, in the light of the
        circumstances under which they were made, not misleading;

               (ii) against any and all loss, liability, claim, damage and
        expense whatsoever, as incurred, to the extent of the aggregate amount
        paid in settlement of any litigation, or any investigation or proceeding
        by any governmental agency or body, commenced or threatened, or of any
        claim whatsoever based upon any such untrue statement or omission, or
        any such alleged untrue statement or omission, provided that (subject to
        Section 6(d) below) any such settlement is effected with the prior
        written consent of the Company; and

               (iii) against any and all expense whatsoever, as incurred
        (including the fees and disbursements of counsel), reasonably incurred
        in investigating, preparing or defending against any litigation, or any
        investigation or proceeding by any governmental agency or body,
        commenced or threatened, or any claim whatsoever based upon any such
        untrue statement or omission, or any such alleged untrue statement or
        omission, to the extent that any such expense is not paid under (i) or
        (ii) above;

provided, however, that this indemnity agreement shall not apply to any loss,
liability, claim, damage or expense to the extent arising out of any untrue
statement or omission or alleged untrue statement or omission made in reliance
upon and in conformity with written information furnished to the Company by the
Purchaser or such holder of Registrable Securities (which also acknowledges the
indemnity provisions herein) and each person, if any, who controls the Purchaser
or any such holder of Registrable Securities expressly for use in the
Registration Statement (or any amendment thereto), or any preliminary prospectus
or the Prospectus (or any amendment or supplement thereto).

               (b) In connection with any Shelf Registration in which a holder,
including, without limitation, the Purchaser, of Registrable Securities is
participating, in furnishing information relating to such holder of Registrable
Securities to the Company in writing expressly for use in such Registration
Statement, any preliminary prospectus, the Prospectus or any

                                       13
<PAGE>   14

amendments or supplements thereto, the holders of such Registrable Securities
agree, severally and not jointly, to indemnify and hold harmless the Purchaser
and each person, if any, who controls the Purchaser within the meaning of either
Section 15 of the Securities Act or Section 20 of the Exchange Act and the
Company, and each person, if any, who controls the Company within the meaning of
either such Section, against any and all loss, liability, claim, damage and
expense described in the indemnity contained in subsection (a) of this Section,
as incurred, but only with respect to untrue statements or omissions, or alleged
untrue statements or omissions, made in the Registration Statement (or any
amendment thereto), or any preliminary prospectus or the Prospectus (or any
amendment or supplement thereto) in reliance upon and in conformity with written
information furnished to the Company by such holder of Registrable Securities
(which also acknowledges the indemnity provisions herein) and each person, if
any, who controls any such holder of Registrable Securities expressly for use in
the Registration Statement (or any amendment thereto) or such preliminary
prospectus or the Prospectus (or any amendment or supplement thereto).

               The Purchaser agrees to indemnify and hold harmless the Company,
the holders of Registrable Securities, and each person, if any, who controls the
Company or any holder of Registrable Securities within the meaning of either
Section 15 of the Securities Act or Section 20 of the Exchange Act against any
and all loss, liability, claim, damage and expense described in the indemnity
contained in subsection (a) of this Section, as incurred, but only with respect
to untrue statements or omissions, or alleged untrue statements or omissions,
made in the Registration Statement (or any amendment thereto), or any
preliminary prospectus or the Prospectus (or any amendment or supplement
thereto) in reliance upon and in conformity with written information furnished
to the Company by the Purchaser expressly for use in the Registration Statement
(or any amendment thereto) or such preliminary prospectus or the Prospectus (or
any amendment or supplement thereto).

               (c) Each indemnified party shall give notice as promptly as
reasonably practicable to each indemnifying party of any action commenced
against it in respect of which indemnity may be sought hereunder, but failure to
so notify an indemnifying party shall not relieve such indemnifying party from
any liability hereunder to the extent it is not materially prejudiced as a
result thereof and in any event shall not relieve it from any liability which it
may have otherwise than on account of this indemnity agreement. An indemnifying
party may participate at its own expense in the defense of any such action;
provided, however, that counsel to the indemnifying party shall not (except with
the consent of the indemnified party) also be counsel to the indemnified party.
In no event shall the indemnifying parties be liable for fees and expenses of
more than one counsel (in addition to any local counsel) separate from their own
counsel for all indemnified parties in connection with any one action or
separate but similar or related actions in the same jurisdiction arising out of
the same general allegations or circumstances. No indemnifying party shall,
without the prior written consent of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any
litigation, or any investigation or proceeding by any governmental agency or
body, commenced or threatened, or any claim whatsoever in respect of which
indemnification or contribution could be sought under this Section 6 hereof
(whether or not the indemnified parties are actual or potential parties
thereto), unless such settlement, compromise or consent (i) includes an
unconditional release of each indemnified party from all liability arising out
of such litigation,

                                       14
<PAGE>   15

investigation, proceeding or claim and (ii) does not include a statement as to
or an admission of fault, culpability or a failure to act by or on behalf of any
indemnified party.

               (d) If at any time an indemnified party shall have requested an
indemnifying party to reimburse the indemnified party for fees and expenses of
counsel, such indemnifying party agrees that it shall be liable for any
settlement of the nature contemplated by Section 6(a)(ii) effected without its
written consent if (i) such settlement is entered into more than 45 days after
receipt by such indemnifying party of aforesaid request, (ii) such indemnifying
party shall have received notice of the terms of such settlement at least 30
days prior to such settlement being entered into and (iii) such indemnifying
party shall not have reimbursed such indemnified party in accordance with such
request prior to the date of such settlement.

               (e) If the indemnification provided for in this Section 6 is for
any reason unavailable to or insufficient to hold harmless an indemnified party
in respect of any losses, liabilities, claims, damages or expenses referred to
therein, then each indemnifying party shall contribute to the aggregate amount
of such losses, liabilities, claims, damages and expenses incurred by such
indemnified party, as incurred, in such proportion as is appropriate to reflect
the relative fault of the indemnifying party or parties on the one hand and of
the indemnified party on the other hand in connection with the statements or
omissions which resulted in such losses, liabilities, claims, damages or
expenses, as well as any other relevant equitable considerations.

               The relative fault of the Company on the one hand and the holders
of the Registrable Securities or the Purchaser on the other hand shall be
determined by reference to, among other things, whether any such untrue or
alleged untrue statement of a material fact or omission or alleged omission to
state a material fact relates to information supplied by the Company or by the
holder of the Registrable Securities or the Purchaser and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission.

               The parties hereto agree that it would not be just and equitable
if contribution pursuant to this Section 6(e) were determined by pro rata
allocation or by any other method of allocation which does not take account of
the equitable considerations referred to above in this Section 6(e). The
aggregate amount of losses, liabilities, claims, damages, and expenses incurred
by an indemnified party and referred to above in this Section 6(e) shall be
deemed to include any legal or other expenses reasonably incurred by such
indemnified party in investigating, preparing or defending against any
litigation, or any investigation or proceeding by any governmental agency or
body, commenced or threatened, or any claim whatsoever based upon any such
untrue or alleged untrue statement or omission or alleged omission.

               Notwithstanding the provisions of this Section 6, neither the
holder of any Registrable Securities nor the Purchaser, shall be required to
indemnify or contribute any amount in excess of the amount by which the total
price at which the Registrable Securities sold by such holder of Registrable
Securities or unwritten by the Purchaser, as the case may be, and distributed to
the public were offered to the public exceeds the amount of any damages that
such holder of Registrable Securities or the Purchaser has otherwise been
required to pay by reason of such untrue or alleged untrue statement or omission
or alleged omission.

                                       15
<PAGE>   16

               No person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Securities Act) shall be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation.

               For purposes of this Section 6(e), each person, if any, who
controls the Purchaser or any holder of Registrable Securities within the
meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act
shall have the same rights to contribution as the Purchaser or such holder, and
each person, if any, who controls the Company within the meaning of Section 15
of the Securities Act or Section 20 of the Exchange Act shall have the same
rights to contribution as the Company.

               Section 7. Information Requirements. The Company covenants that,
if at any time before the end of the Effectiveness Period the Company is not
subject to the reporting requirements of the Exchange Act, it will cooperate
with any Holder of Registrable Securities and take such further reasonable
action as any Holder of Registrable Securities may reasonably request in writing
(including, without limitation, making such reasonable representations as any
such Holder may reasonably request), all to the extent required from time to
time to enable such Holder to sell Registrable Securities without registration
under the Securities Act within the limitation of the exemptions provided by
Rule 144 and Rule 144A under the Securities Act and customarily taken in
connection with sales pursuant to such exemptions. Upon the written request of
any Holder of Registrable Securities, the Company shall deliver to such Holder a
written statement as to whether it has complied with such filing requirements,
unless such a statement has been included in the Company's most recent report
required to be filed and filed pursuant to Section 13 or Section 15(d) of
Exchange Act. Notwithstanding the foregoing, nothing in this Section 7 shall be
deemed to require the Company to register any of its securities (other than the
Common Stock) under any section of the Exchange Act.

               Section 8. Miscellaneous.

               (a) No Conflicting Agreements. The Company is not, as of the date
hereof, a party to, nor shall it, on or after the date of this Agreement, enter
into, any agreement with respect to its securities that conflicts with the
rights granted to the Holders of Registrable Securities in this Agreement. The
Company represents and warrants that the rights granted to the Holders of
Registrable Securities hereunder do not in any way conflict with the rights
granted to the holders of the Company's securities under any other agreements.

               (b) Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Company has obtained the written consent of Holders
of a majority of the then outstanding Underlying Common Stock constituting
Registrable Securities (with Holders of LYONs deemed to be the Holders, for
purposes of this Section, of the number of outstanding shares of Underlying
Common Stock into which such LYONs are or would be convertible or exchangeable
as of the date on which such consent is requested). Notwithstanding the
foregoing, a waiver or consent to depart from the provisions hereof with respect
to a matter that relates exclusively to the rights of Holders of Registrable
Securities whose securities are being sold pursuant to a Registration Statement
and that does not directly or indirectly affect the rights of other Holders of
Registrable

                                       16
<PAGE>   17

Securities may be given by Holders of at least a majority of the Registrable
Securities being sold by such Holders pursuant to such Registration Statement;
provided, that the provisions of this sentence may not be amended, modified, or
supplemented except in accordance with the provisions of the immediately
preceding sentence. Each Holder of Registrable Securities outstanding at the
time of any such amendment, modification, supplement, waiver or consent or
thereafter shall be bound by any such amendment, modification, supplement,
waiver or consent effected pursuant to this Section 8(b), whether or not any
notice, writing or marking indicating such amendment, modification, supplement,
waiver or consent appears on the Registrable Securities or is delivered to such
Holder.

               (c) Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand delivery, by telecopier, by
courier guaranteeing overnight delivery or by first-class mail, return receipt
requested, and shall be deemed given (i) when made, if made by hand delivery,
(ii) upon confirmation, if made by telecopier, (iii) one (1) Business Day after
being deposited with such courier, if made by overnight courier or (iv) on the
date indicated on the notice of receipt, if made by first-class mail, to the
parties as follows:

               (w) if to a Holder of Registrable Securities, at the most current
        address given by such Holder to the Company in a Notice and
        Questionnaire or any amendment thereto;

               (x) if to the Company, to:

               Allergan, Inc.
               2525 Dupont Drive
               Irvine, CA  92612
               Attention: General Counsel
               Telecopy No.: (714) 264-6987

               and

               (y) if to the Purchaser, to:

               Merrill Lynch & Co., Merrill Lynch, Pierce, Fenner & Smith
               Incorporated
               World Financial Center
               North Tower
               250 Vesey Street
               New York, New York  10281
               Attention: Syndicate Department
               Telecopy No.: (212) 449-1000

or to such other address as such person may have furnished to the other persons
identified in this Section 8(c) in writing in accordance herewith.

               (d) Approval of Holders. Whenever the consent or approval of
Holders of a specified percentage of Registrable Securities is required
hereunder, Registrable Securities held by the Company or its affiliates (as such
term is defined in Rule 405 under the Securities Act) (other than the Purchaser
or subsequent Holders of Registrable Securities if such subsequent Holders are
deemed to be such affiliates solely by reason of their holdings of such
Registrable

                                       17
<PAGE>   18

Securities) shall not be counted in determining whether such consent or approval
was given by the Holders of such required percentage.

               (e) Successors and Assigns. Any person who purchases any
Registrable Securities from the Purchaser shall be deemed, for purposes of this
Agreement, to be an assignee of the Purchaser. This Agreement shall inure to the
benefit of and be binding upon the successors and assigns of each of the parties
and shall inure to the benefit of and be binding upon each Holder of any
Registrable Securities.

               (f) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be original and all of which taken together
shall constitute one and the same agreement.

               (g) Headings. The headings in this Agreement are for convenience
of reference only and shall not limit or otherwise affect the meaning hereof.

               (h) Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD
TO CONFLICTS OF LAWS PRINCIPLES THEREOF.

               (i) Severability. If any term, provision, covenant or restriction
of this Agreement is held to be invalid, illegal, void or unenforceable, the
remainder of the terms, provisions, covenants and restrictions set forth herein
shall remain in full force and effect and shall in no way be affected, impaired
or invalidated thereby, and the parties hereto shall use their best efforts to
find and employ an alternative means to achieve the same or substantially the
same result as that contemplated by such term, provision, covenant or
restriction, it being intended that all of the rights and privileges of the
parties shall be enforceable to the fullest extent permitted by law.

               (j) Entire Agreement. This Agreement is intended by the parties
as a final expression of their agreement and is intended to be a complete and
exclusive statement of the agreement and understanding of the parties hereto in
respect of the subject matter contained herein and the registration rights
granted by the Company with respect to the Registrable Securities. Except as
provided in the Purchase Agreement, there are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein,
with respect to the registration rights granted by the Company with respect to
the Registrable Securities. This Agreement supersedes all prior agreements and
undertakings among the parties with respect to such registration rights.

               (k) Termination. This Agreement and the obligations of the
parties hereunder shall terminate upon the end of the Effectiveness Period,
except for any liabilities or obligations under Sections 4, 5 or 6 hereof and
the obligations to make payments of and provide for liquidated damages under
Section 2(e) hereof to the extent such damages accrue prior to the end of the
Effectiveness Period, each of which shall remain in effect in accordance with
its terms.

               [Remainder of this page intentionally left blank]

                                       18
<PAGE>   19

               IN WITNESS WHEREOF, the parties have executed this Registration
Rights Agreement as of the date first written above.

ALLERGAN, INC.

By: /s/ ERIC K. BRANDT
    -----------------------------------------
    Eric K. Brandt
    Corporate Vice President and
    Chief Financial Officer

Accepted as of the date first above written:

MERRILL LYNCH & CO.,
MERRILL LYNCH, PIERCE, FENNER & SMITH INCORPORATED

By: /s/ JAMES J. KARRELS
    -----------------------------------------
Name:   James J. Karrels
Title:  Vice President<PAGE>   1

                                                                EXHIBIT 10.56(a)

                               ALTERA CORPORATION
                   2000 NON-QUALIFIED STOCK OPTION PLAN NO. 1

        1. Purposes of the Plan. The purposes of this Non-Qualified Stock Option
Plan are to attract and retain the best available personnel, to provide
additional incentive to Employees and to promote the success of the Company's
business.

        2. Definitions. As used herein, the following definitions shall apply:

                (a) "Administrator" means the Board or any of the Committees
appointed to administer the Plan.

                (b) "Affiliate" and "Associate" shall have the respective
meanings ascribed to such terms in Rule 12b-2 promulgated under the Exchange
Act.

                (c) "Applicable Laws" means the legal requirements relating to
the administration of stock incentive plans, if any, under applicable provisions
of federal securities laws, state corporate and securities laws, the Code, the
rules of any applicable stock exchange or national market system, and the rules
of any foreign jurisdiction applicable to Options granted to residents therein.

                (d) "Approved Leave of Absence" means any leave at the end of
which an Employee is guaranteed by law or contract that such Employee will be
reinstated to the same or a similar position, military leave, or any other
personal leave that has been authorized by the Administrator.

                (e) "Board" means the Board of Directors of the Company.

                (f) "Code" means the Internal Revenue Code of 1986, as amended.

                (g) "Committee" means any committee appointed by the Board to
administer the Plan.

                (h) "Common Stock" means the common stock of the Company.

                (i) "Company" means Altera Corporation, a Delaware corporation.

                (j) "Continuous Service" means that the provision of services to
the Company or a Related Entity in any capacity of Employee is not interrupted
or terminated. Continuous Service shall not be considered interrupted in the
case of (i) any Approved Leave of Absence, (ii) transfers among the Company, any
Related Entity, or any successor, in any capacity of Employee, or (iii) any
change in status as long as the individual remains an Employee of the Company or
a Related Entity (except as otherwise provided in the Option Agreement).

                (k) "Corporate Transaction" means any of the following
transactions:

                        (i) a merger or consolidation in which the Company is
        not the surviving entity, except for a transaction the principal purpose
        of which is to change the state in which the Company is incorporated;

                        (ii) the sale, transfer or other disposition of all or
        substantially all of the assets of the Company (including the capital
        stock of the Company's subsidiary corporations); or

                                       1
<PAGE>   2

                        (iii) any reverse merger in which the Company is the
        surviving entity but in which securities possessing more than fifty
        percent (50%) of the total combined voting power of the Company's
        outstanding securities are transferred to a person or persons different
        from those who held such securities immediately prior to such merger.

                (l) "Director" means a member of the Board or the board of
directors of any Related Entity.

                (m) "Disability" means a Grantee would qualify for benefit
payments under the long-term disability insurance policy of the Company or the
Related Entity to which the Grantee provides services regardless of whether the
Grantee is covered by such policy. If the Company or the Related Entity to which
the Grantee provides service does not have a long-term disability insurance
policy in place, "Disability" means that a Grantee is permanently unable to
carry out the responsibilities and functions of the position held by the Grantee
by reason of any medically determinable physical or mental impairment. A Grantee
will not be considered to have incurred a Disability unless he or she furnishes
proof of such impairment sufficient to satisfy the Administrator in its
discretion.

                (n) "Employee" means any person, including an Officer or
Director, who is an employee of the Company or any Related Entity. Neither
service as a Director nor the payment of a director's fee by the Company or a
Related Entity shall be sufficient to constitute "employment" by the Company.

                (o) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                (p) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                        (i) Where there exists a public market for the Common
        Stock, the Fair Market Value shall be (A) the closing price for a Share
        for the last market trading day prior to the time of the determination
        (or, if no closing price was reported on that date, on the last trading
        date on which a closing price was reported) on the stock exchange
        determined by the Administrator to be the primary market for the Common
        Stock or the Nasdaq National Market, whichever is applicable or (B) if
        the Common Stock is not traded on any such exchange or national market
        system, the average of the high bid and low asked prices of a Share on
        the Nasdaq Small Cap Market for the day prior to the time of the
        determination (or, if no such prices were reported on that date, on the
        last date on which such prices were reported), in each case, as reported
        in The Wall Street Journal or such other source as the Administrator
        deems reliable; or

                        (ii) In the absence of an established market for the
        Common Stock of the type described in (i), above, the Fair Market Value
        thereof shall be determined by the Administrator in good faith.

                (q) "Grantee" means an Employee who receives an Option pursuant
to an Option Agreement under the Plan.

                (r) "Officer" means a person who is an officer of the Company or
a Related Entity within the meaning of Section 16 of the Exchange Act and the
rules and regulations promulgated thereunder.

                                       2
<PAGE>   3

                (s) "Option" means an option to purchase Shares pursuant to an
Option Agreement granted under the Plan not intended to qualify as an incentive
stock option within the meaning of Section 422 of the Code.

                (t) "Option Agreement" means the written agreement evidencing
the grant of an Option executed by the Company and the Grantee, including any
amendments thereto.

                (u) "Parent" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

                (v) "Plan" means this 2000 Non-Qualified Stock Option Plan No.
1.

                (w) "Related Entity" means any Parent, Subsidiary and any
business, corporation, partnership, limited liability company or other entity in
which the Company, a Parent or a Subsidiary holds a substantial ownership
interest, directly or indirectly.

                (x) "Rule 16b-3" means Rule 16b-3 promulgated under the Exchange
Act or any successor thereto.

                (y) "Share" means a share of the Common Stock.

                (z) "Subsidiary" means a "subsidiary corporation," whether now
or hereafter existing, as defined in Section 424(f) of the Code.

        3. Stock Subject to the Plan.

                (a) Subject to the provisions of Section 10 below, the maximum
aggregate number of Shares that may be issued pursuant to all Options is 153,945
Shares. The Shares to be issued pursuant to Options may be authorized, but
unissued, or reacquired Common Stock.

                (b) Any Shares covered by an Option (or portion of an Option)
which is forfeited or canceled, expires or is settled in cash, shall be deemed
to have been issued for purposes of determining the maximum aggregate number of
Shares which may be issued under the Plan. Shares that actually have been issued
under the Plan pursuant to an Option shall not be returned to the Plan and shall
not become available for future issuance under the Plan.

        4. Administration of the Plan.

                (a) Plan Administrator.

                        (i) Administration with Respect to Directors and
        Officers. With respect to grants of Options to Employees who are also
        Officers or Directors of the Company, the Plan shall be administered by
        (A) the Board or (B) a Committee designated by the Board, which
        Committee shall be constituted in such a manner as to satisfy the
        Applicable Laws and to permit such grants and related transactions under
        the Plan to be exempt from Section 16(b) of the Exchange Act in
        accordance with Rule 16b-3. Once appointed, such Committee shall
        continue to serve in its designated capacity until otherwise directed by
        the Board.

                                       3
<PAGE>   4

                        (ii) Administration With Respect to Other Employees.
        With respect to grants of Options to Employees who are neither Directors
        nor Officers of the Company, the Plan shall be administered by (A) the
        Board or (B) a Committee designated by the Board, which Committee shall
        be constituted in such a manner as to satisfy the Applicable Laws. Once
        appointed, such Committee shall continue to serve in its designated
        capacity until otherwise directed by the Board. The Board may authorize
        one or more Officers to grant such Options and may limit such authority
        as the Board determines from time to time.

                        (iii) Administration Errors. If an Option is granted in
        a manner inconsistent with the provisions of this subsection (a), such
        Option shall be presumptively valid as of its grant date to the extent
        permitted by the Applicable Laws.

                (b) Powers of the Administrator. Subject to Applicable Laws and
the provisions of the Plan (including any other powers given to the
Administrator hereunder), and except as otherwise provided by the Board, the
Administrator shall have the authority, in its discretion:

                        (i) to select the Employees to whom Options may be
        granted from time to time hereunder;

                        (ii) to determine whether and to what extent Options are
        granted hereunder;

                        (iii) to determine the number of Shares or the amount of
        other consideration to be covered by each Option granted hereunder;

                        (iv) to approve forms of Option Agreements for use under
        the Plan;

                        (v) to determine the terms and conditions of any Option
        granted hereunder;

                        (vi) to amend the terms of any outstanding Option
        granted under the Plan, provided that any amendment that would adversely
        affect the Grantee's rights under an outstanding Option shall not be
        made without the Grantee's written consent;

                        (vii) to construe and interpret the terms of the Plan
        and Options granted pursuant to the Plan, including without limitation,
        any notice of Option or Option Agreement, granted pursuant to the Plan;

                        (viii) to establish additional terms, conditions, rules
        or procedures to accommodate the rules or laws of applicable foreign
        jurisdictions and to afford Grantees favorable treatment under such
        laws; provided, however, that no Option shall be granted under any such
        additional terms, conditions, rules or procedures with terms or
        conditions which are inconsistent with the provisions of the Plan; and

                        (ix) to take such other action, not inconsistent with
        the terms of the Plan, as the Administrator deems appropriate.

        5. Eligibility. Options may be granted to Employees.

                                       4
<PAGE>   5

        6. Terms and Conditions of Options.

                (a) Conditions of Option. Subject to the terms of the Plan, the
Administrator shall determine the provisions, terms, and conditions of each
Option including, but not limited to, the Option vesting schedule, repurchase
provisions, rights of first refusal, forfeiture provisions, form of payment
(cash, Shares, or other consideration) upon settlement of the Option, payment
contingencies, and satisfaction of any performance criteria. The performance
criteria established by the Administrator may be based on any one of, or
combination of, increase in share price, earnings per share, total stockholder
return, return on equity, return on assets, return on investment, net operating
income, cash flow, revenue, economic value added, personal management
objectives, or other measure of performance selected by the Administrator.
Partial achievement of the specified criteria may result in a payment or vesting
corresponding to the degree of achievement as specified in the Option Agreement.

                (b) Acquisitions and Other Transactions. The Administrator may
issue Options under the Plan in settlement, assumption or substitution for,
outstanding Options or obligations to grant future Options in connection with
the Company or a Related Entity acquiring another entity, an interest in another
entity or an additional interest in a Related Entity whether by merger, stock
purchase, asset purchase or other form of transaction.

                (c) Deferral of Option Payment. The Administrator may establish
one or more programs under the Plan to permit selected Grantees the opportunity
to elect to defer receipt of consideration upon exercise of an Option,
satisfaction of performance criteria, or other event that absent the election
would entitle the Grantee to payment or receipt of Shares or other consideration
under an Option. The Administrator may establish the election procedures, the
timing of such elections, the mechanisms for payments of, and accrual of
interest or other earnings, if any, on amounts, Shares or other consideration so
deferred, and such other terms, conditions, rules and procedures that the
Administrator deems advisable for the administration of any such deferral
program.

                (d) Separate Programs. The Administrator may establish one or
more separate programs under the Plan for the purpose of issuing particular
forms of Options to one or more classes of Grantees on such terms and conditions
as determined by the Administrator from time to time.

                (e) Buyout Provisions. The Administrator may at any time offer
to buy out for a payment in cash or Shares, an Option previously granted based
on such terms and conditions as the Administrator shall establish and
communicate to the Grantee at the time that such offer is made.

                (f) Early Exercise. The Option Agreement may, but need not,
include a provision whereby the Grantee may elect at any time while an Employee
to exercise any part or all of the Option prior to full vesting of the Option.
Any unvested Shares received pursuant to such exercise may be subject to a
repurchase right in favor of the Company or a Related Entity or to any other
restriction the Administrator determines to be appropriate.

                (g) Term of Option. The term of each Option shall be the term
stated in the Option Agreement.

                (h) Transferability of Options. Options may be transferred by
will and by the laws of descent and distribution or during the Grantee's
lifetime through a domestic relations order to the extent provided in the Option
Agreement or in the manner and to the extent determined by the Administrator.

                                       5
<PAGE>   6

                (i) Time of Granting Options. The date of grant of an Option
shall for all purposes be the date on which the Administrator makes the
determination to grant such Option, or such other date as is determined by the
Administrator. Notice of the grant determination shall be given to each Employee
to whom an Option is so granted within a reasonable time after the date of such
grant.

        7. Option Exercise or Purchase Price, Consideration and Taxes.

                (a) Exercise or Purchase Price. The exercise or purchase price,
if any, for an Option shall be the price determined by the Administrator.

                (b) Consideration. Subject to Applicable Laws, the consideration
to be paid for the Shares to be issued upon exercise or purchase of an Option
including the method of payment, shall be determined by the Administrator. In
addition to any other types of consideration the Administrator may determine,
the Administrator is authorized to accept as consideration for Shares issued
under the Plan the following, provided that the portion of the consideration
equal to the par value of the Shares must be paid in cash or other legal
consideration permitted by the Delaware General Corporation Law:

                        (i) cash;

                        (ii) check;

                        (iii) surrender of Shares or delivery of a properly
        executed form of attestation of ownership of Shares as the Administrator
        may require (including withholding of Shares otherwise deliverable upon
        exercise of the Option) which have a Fair Market Value on the date of
        surrender or attestation equal to the aggregate exercise price of the
        Shares as to which said Option shall be exercised (but only to the
        extent that such exercise of the Option would not result in an
        accounting compensation charge with respect to the Shares used to pay
        the exercise price unless otherwise determined by the Administrator);

                        (iv) payment through a broker-dealer sale and remittance
        procedure pursuant to which the Grantee (A) shall provide written
        instructions to a Company designated brokerage firm to effect the
        immediate sale of some or all of the purchased Shares and remit to the
        Company, out of the sale proceeds available on the settlement date,
        sufficient funds to cover the aggregate exercise price payable for the
        purchased Shares and (B) shall provide written directives to the Company
        to deliver the certificates for the purchased Shares directly to such
        brokerage firm in order to complete the sale transaction;

                        (v) a reduction in the amount of any Company liability
        to the Grantee, including any liability attributable to the Grantee's
        participation in any Company-sponsored deferred compensation program or
        arrangement; or

                        (vi) any combination of the foregoing methods of
        payment.

                (c) Taxes. No Shares shall be delivered under the Plan to any
Grantee or other person until such Grantee or other person has made arrangements
acceptable to the Administrator for the satisfaction of any foreign, federal,
state, or local income and employment tax withholding obligations, including,
without limitation, obligations incident to the receipt of Shares. Upon exercise
of an Option, the Company shall withhold or collect from Grantee an amount
sufficient to satisfy such tax obligations.

                                       6
<PAGE>   7

        8. Exercise of Option.

                (a) Procedure for Exercise; Rights as a Stockholder.

                        (i) Any Option granted hereunder shall be exercisable at
        such times and under such conditions as determined by the Administrator
        under the terms of the Plan and specified in the Option Agreement. No
        Option may be exercised for a fraction of a Share.

                        (ii) An Option shall be deemed to be exercised when (1)
        notice of such exercise has been given to the Company or its authorized
        representative in accordance with the terms of the Option by the person
        entitled to exercise the Option and (2)(a) full payment for the Shares
        with respect to which the Option is exercised has been received by the
        Company or (b) the Shares have been sold as a result of the use of the
        broker-dealer sale and remittance procedure to pay the purchase price as
        provided in Section 7(b)(iv). Until the issuance (as evidenced by the
        appropriate entry on the books of the Company or of a duly authorized
        transfer agent of the Company) of the stock certificate evidencing such
        Shares, no right to vote or receive dividends or any other rights as a
        stockholder shall exist with respect to Shares subject to an Option,
        notwithstanding the exercise of an Option or other Option. The Company
        shall issue (or cause to be issued) such stock certificate promptly upon
        exercise of the Option. No adjustment will be made for a dividend or
        other right for which the record date is prior to the date the stock
        certificate is issued, except as provided in the Option Agreement or
        Section 10 below.

                (b) Exercise of Option Following Termination of Continuous
Service.

                        (i) An Option may not be exercised after the termination
        date of such Option set forth in the Option Agreement and may be
        exercised following the termination of a Grantee's Continuous Service
        only to the extent provided in the Option Agreement.

                        (ii) Where the Option Agreement permits a Grantee to
        exercise an Option following the termination of the Grantee's Continuous
        Service for a specified period, the Option shall terminate to the extent
        not exercised on the last day of the specified period or the last day of
        the original term of the Option, whichever occurs first.

        9. Conditions Upon Issuance of Shares.

                (a) Shares shall not be issued pursuant to the exercise of an
Option unless the exercise of such Option and the issuance and delivery of such
Shares pursuant thereto shall comply with all Applicable Laws, and shall be
further subject to the approval of counsel for the Company with respect to such
compliance.

                (b) As a condition to the exercise of an Option, the Company may
require the person exercising such Option to represent and warrant at the time
of any such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares if, in the
opinion of counsel for the Company, such a representation is required by any
Applicable Laws.

        10. Adjustments Upon Changes in Capitalization. Subject to any required
action by the stockholders of the Company, the number of Shares covered by each
outstanding Option, and the number of Shares which have been authorized for
issuance under the Plan but as to which no Options have yet been granted, the
exercise or purchase price of each such outstanding Option, as well as any other
terms

                                       7
<PAGE>   8

that the Administrator determines require adjustment shall be proportionately
adjusted for (i) any increase or decrease in the number of issued Shares
resulting from a stock split, reverse stock split, stock dividend, combination
or reclassification of the Shares, or similar event affecting the Shares, (ii)
any other increase or decrease in the number of issued Shares effected without
receipt of consideration by the Company, or (iii) as the Administrator may
determine in its discretion, any other transaction with respect to Common Stock
to which Section 424(a) of the Code applies or any similar transaction;
provided, however that conversion of any convertible securities of the Company
shall not be deemed to have been "effected without receipt of consideration."
Such adjustment shall be made by the Administrator and its determination shall
be final, binding and conclusive. Except as the Administrator determines, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason hereof shall be made with respect to, the number or price of Shares
subject to an Option.

        11. Dissolution or Liquidation; Corporate Transaction.

                (a) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Administrator shall notify each
Grantee as soon as practicable prior to the effective date of such proposed
transaction. The Administrator in its discretion may provide for Grantee to have
the right to exercise his or her Option prior to such transaction as to all of
the Shares covered thereby, including Shares as to which the Option would not
otherwise be exercisable. In addition, the Administrator may provide that any
Company repurchase option applicable to any Shares purchased upon exercise of an
Option shall lapse as to all such Shares, provided the proposed dissolution or
liquidation takes place at the time and in the manner contemplated. To the
extent it has not been previously exercised, an Option will terminate
immediately prior to the consummation of such proposed transaction.

                (b) Corporate Transaction. In the event of a Corporate
Transaction, each Option which is at the time outstanding under the Plan shall
automatically become fully vested and exercisable and be released from any
restrictions on transfer and repurchase or forfeiture rights, immediately prior
to the specified effective date of such Corporate Transaction, for all of the
Shares at the time represented by such Option if the Option is not assumed by
the successor corporation or the Parent thereof in connection with the Corporate
Transaction. For the purposes of accelerating the vesting and the release of
restrictions applicable to Options pursuant to this subsection (but not for
purposes of termination of such Options), the Option shall be considered assumed
if, in connection with the Corporate Transaction, the option or right confers
the right to purchase or receive, for each Share subject to the Option
immediately prior to the Corporate Transaction, the consideration (whether
stock, cash, or other securities or property) received in the Corporate
Transaction by holders of Common Stock for each Share held on the effective date
of the transaction (and if holders were offered a choice of consideration, the
type of consideration chosen by the holders of a majority of the outstanding
Shares) under vesting and terms that give effect to the vesting and terms of the
Options surrendered; provided, however, that if such consideration received in
the Corporate Transaction was not solely common stock of the successor
corporation or its Parent, the Administrator may, with the consent of the
successor corporation, provide for the consideration to be received upon the
exercise of the Option, for each Share of Optioned Stock subject to the Option,
to be solely common stock of the successor corporation or its Parent equal in
fair market value to the per share consideration received by holders of Common
Stock in the Corporate Transaction. The determination of Option comparability
above shall be made by the Administrator and its determination shall be final,
binding and conclusive. Effective upon the consummation of the Corporate
Transaction, all outstanding Options under the Plan shall terminate. However,
all such Options shall not terminate if the Options are, in connection with the
Corporate Transaction, assumed by the successor corporation or Parent thereof.

                                       8
<PAGE>   9

        12. Effective Date and Term of Plan. The Plan shall become effective
upon the adoption by the Board of the Company. It shall continue in effect for a
term of ten (10) years unless sooner terminated. Subject to Applicable Laws,
Options may be granted under the Plan upon its becoming effective.

        13. Amendment, Suspension or Termination of the Plan.

                (a) The Board may at any time amend, suspend or terminate the
Plan. To the extent necessary to comply with Applicable Laws, the Company shall
obtain stockholder approval of any Plan amendment in such a manner and to such a
degree as required.

                (b) No Option may be granted during any suspension of the Plan
or after termination of the Plan.

                (c) Any amendment, suspension or termination of the Plan
(including termination of the Plan under Section 12 above) shall not affect
Options already granted, and such Options shall remain in full force and effect
as if the Plan had not been amended, suspended or terminated, unless mutually
agreed otherwise between the Grantee and the Administrator, which agreement must
be in writing and signed by the Grantee and the Company.

        14. Reservation of Shares.

                (a) The Company, during the term of the Plan, will at all times
reserve and keep available such number of Shares as shall be sufficient to
satisfy the requirements of the Plan.

                (b) The inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company's
counsel to be necessary to the lawful issuance and sale of any Shares hereunder,
shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained.

        15. No Effect on Terms of Employment. The Plan shall not confer upon any
Grantee any right with respect to the Grantee's Continuous Service, nor shall it
interfere in any way with his or her right or the Company's right to terminate
the Grantee's Continuous Service at any time, for any reason.

        16. No Effect on Retirement and Other Benefit Plans. Except as
specifically provided in a retirement or other benefit plan of the Company or a
Related Entity, Options shall not be deemed compensation for purposes of
computing benefits or contributions under any retirement plan of the Company or
a Related Entity, and shall not affect any benefits under any other benefit plan
of any kind or any benefit plan subsequently instituted under which the
availability or amount of benefits is related to level of compensation. The Plan
is not a "Retirement Plan" or "Welfare Plan" under the Employee Retirement
Income Security Act of 1974, as amended.

                                       9

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