OCCULOGIX, INC.

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

                             Underwriting Agreement

                                                              New York, New York
                                                                  [      ], 2004

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


Ladies and Gentlemen:

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


- ----------

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





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

     1.   Representations and Warranties.

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

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

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


                                     - 2 -


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

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



                                     - 3 -

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

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

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



                                     - 4 -




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

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

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

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




                                     - 5 -



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

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

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

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



                                     - 6 -



     applicable accounting requirements of Regulation S-X under the Act and the
     Canadian Securities Laws and the pro forma adjustments have been properly
     applied to the historical amounts in the compilation of those statements.

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

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

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

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

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



                                     - 7 -



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

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

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

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

               (w)  The Company and its subsidiaries possess all licenses,
     certificates, permits and other authorizations issued by the appropriate
     federal, state, provincial, municipal or foreign regulatory authorities
     necessary to conduct their respective businesses, except for any which the
     failure to possess could not reasonably be expected to have a Material
     Adverse Effect, except as set forth in or contemplated in the Prospectus
     (exclusive of any supplement thereto), and neither the Company nor any such



                                     - 8 -


     subsidiary has received any notice of proceedings relating to the
     revocation or modification of any such certificate, authorization or permit
     which, singly or in the aggregate, if the subject of an unfavorable
     decision, ruling or finding, would have a Material Adverse Effect, except
     as set forth in or contemplated in the Prospectus (exclusive of any
     supplement thereto).

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

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

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

               (aa) In the ordinary course of its business, the Company
     periodically reviews the effect of Environmental Laws on the business,
     operations and properties of the Company and its subsidiaries, in the
     course of which it identifies and evaluates associated costs and
     liabilities (including, without limitation, any capital or operating
     expenditures required for clean-up, closure of properties or compliance
     with Environmental Laws, or any permit, license or approval, any related
     constraints on operating activities and any potential liabilities to third
     parties). On the basis of such review, the Company has reasonably concluded
     that such associated costs and liabilities would not, singly or in the
     aggregate, have a Material Adverse Effect, except as set forth in or
     contemplated in the Prospectus (exclusive of any supplement thereto).



                                     - 9 -



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

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

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

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

               (ee) The operations of the Company and its subsidiaries are and
     have been conducted at all times in compliance with applicable financial
     recordkeeping and reporting requirements of the Currency and Foreign
     Transactions Reporting Act of 1970, as amended, the money laundering
     statutes of all jurisdictions, the rules and regulations thereunder and any
     related or similar rules, regulations or guidelines, issued, administered



                                     - 10 -


     or enforced by any Governmental Authority (collectively, the "Money
     Laundering Laws") and no action, suit or proceeding by or before any court
     or Governmental Authority or any arbitrator involving the Company or any of
     its subsidiaries with respect to the Money Laundering Laws is pending or,
     to the best knowledge of the Company, threatened.

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

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

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



                                     - 11 -



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

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

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

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

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

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

     Furthermore, the Company represents and warrants to Citigroup Global
Markets Inc. that (i) the Registration Statement, the Prospectus and any
preliminary prospectus comply, and any further amendments or supplements thereto
will comply, with any applicable laws or regulations of foreign jurisdictions in
which the Prospectus or any preliminary prospectus, as amended or supplemented,
if applicable, are distributed in connection with the Directed Share Program,
and that (ii) no authorization, approval, consent, license, order, registration
or qualification of or with any Governmental Authority or court, other than such
as have been obtained, is necessary under the securities laws and regulations of
foreign jurisdictions in which the Directed Shares are offered outside the
United States. The Company has not offered, or caused the Underwriters to offer,
Securities to any person pursuant to the Directed Share Program with the
specific intent to unlawfully influence (x) a customer or supplier of the
Company to alter the customer's or



                                     - 12 -


supplier's level or type of business with the Company, or (y) a trade journalist
or publication to write or publish favorable information about the Company or
its products.

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

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

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

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

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



                                     - 13 -


     regardless of whether or not the Custodian shall have received notice of
     such death, incapacity or other event.

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

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

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

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

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



                                     - 14 -


     2.  Purchase and Sale.

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

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

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



                                     - 15 -


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

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

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

     5.   Agreements.

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

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

               (b)  The Company shall deliver to the Underwriters
     contemporaneously, as nearly as practicable, with the execution and
     delivery of this Agreement: (i) a copy of the Canadian Preliminary
     Prospectus and the Canadian Final Prospectus in each of the French and the
     English language signed and certified as required by the Canadian
     Securities Laws in each of the Canadian Qualifying Jurisdictions; (ii) a
     copy of all such documents and certificates that were filed with the
     Canadian Preliminary Prospectus and the Canadian Final Prospectus under
     Canadian Securities Laws; (iii) an opinion of its auditors, Ernst & Young
     LLP, addressed to the Underwriters and their counsel, in form and substance
     satisfactory to the Underwriters



                                     - 16 -


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

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

               (d)  The Company will notify the Underwriters promptly, and
     confirm the notice in writing, when any amendment to the Registration
     Statement has been filed with the Commission or has become effective, and
     when the Canadian Supplemental PREP Prospectus containing the PREP
     information, or any amended Canadian Prospectus, U.S. Prospectus or any
     supplement thereto (collectively, "Supplementary Material") shall have been
     filed, in which case the Company shall deliver to the Underwriters all
     signed and certified copies of such Supplementary Material in the English
     and French languages along with all documents similar to those referred to
     in Section 5(i)(b)(i) (ii), (iii) and (iv) and such other documents as the
     Underwriters may reasonably request. Prior to the termination of the
     offering of the Securities and the Distribution, the Company will not file
     any amendment of the Registration Statement or supplement to the U.S.
     Prospectus or any Rule 462(b) Registration Statement or the U.S. Prospectus
     or any amendment to the Canadian Prospectus or the Canadian Supplemental
     PREP Prospectus unless the Company has furnished to the Underwriters a copy
     for their



                                     - 17 -


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

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

               (f)  Commencing on the date hereof and until the later of (1) the
     completion of the Distribution, or (2) the time at which the Act no longer
     requires a



                                     - 18 -



     prospectus relating to the Securities to be delivered, the Company shall
     promptly notify the Underwriters in writing of:

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

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

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

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

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

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



                                     - 19 -


     in all respects with the Underwriters to allow and assist the Underwriters
     to participate in the preparation of any Supplementary Material and to
     conduct all due diligence investigations which the Underwriters deem
     appropriate in order to fulfill their obligations as underwriters and to
     enable the Underwriters to responsibly execute any certificate related to
     such Supplementary Material required to be executed by them.

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

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

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

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



                                     - 20 -


     Agreement, provided, however, that the Company may issue and sell Common
     Stock pursuant to any employee stock option plan (and may issue options
     thereunder), stock ownership plan or dividend reinvestment plan of the
     Company in effect at the Execution Time and the Company may issue Common
     Stock issuable upon the conversion of securities or the exercise of
     warrants outstanding at the Execution Time.

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

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

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

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



                                     - 21 -


     counsel for the Underwriters relating to such filings); (ix) the
     transportation and other expenses incurred by or on behalf of Company
     representatives in connection with presentations to prospective purchasers
     of the Securities; (x) the fees and expenses of the Company's accountants
     and the fees and expenses of counsel (including local and special counsel)
     for the Company; and (xi) all other costs and expenses incident to the
     performance by the Company and the Selling Stockholders of their
     obligations hereunder.

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

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

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

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

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

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

               (c)  Such Selling Stockholder will advise you promptly, and if
     requested by you, will confirm such advice in writing, so long as delivery
     of a prospectus relating to the Securities by an underwriter or dealer may
     be required under the Act, of (i)



                                     - 22 -


     any material change in the Company's condition (financial or otherwise),
     prospects, earnings, business or properties, (ii) any change in information
     in the Registration Statement or the Prospectus relating to such Selling
     Stockholder or (iii) any new material information relating to the Company
     or relating to any matter stated in the Prospectus which comes to the
     attention of such Selling Stockholder.

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

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

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

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

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

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

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

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



                                     - 23 -



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

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

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

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

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

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



                                     - 24 -


               business as a foreign corporation and is in good standing under
               the laws of each jurisdiction set forth on Schedule A to such
               counsel's opinion;

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

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

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



                                     - 25 -



               Registration Statement or Prospectus, or to be filed as an
               exhibit thereto, which is not described or filed as required; and
               the statements in the Prospectus under the headings "Risk Factors
               - We currently depend on single sources for key components of our
               RHEO System. The loss of any of these sources could delay our
               clinical trials or prevent or delay commercialization of our RHEO
               System," "Risk Factors - Future sales of our common stock could
               reduce our stock price," "Business - Supplier Relationships,"
               "Reorganization," "Management," "Certain Relationships and
               Related Party Transactions," "Description of Capital Stock" and
               "Shares Eligible for Future Sale," insofar as such statements
               summarize legal matters, agreements, documents or legal
               proceedings discussed therein, are accurate and fair summaries,
               in all material respects, of such legal matters, agreements,
               documents or legal proceedings;

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

                    (vi)  all necessary corporate action has been taken by the
               Company to authorize the execution and delivery of each of the
               Canadian Preliminary Prospectus and the Canadian Final Prospectus
               and the filing thereof and the Canadian Supplemental PREP
               Prospectus under Canadian Securities Laws in each of the Canadian
               Qualifying Jurisdictions;

                    (vii) all documents have been filed and all requisite
               proceedings have been taken and all approvals, permits, consents
               and authorizations of appropriate regulatory authorities under
               Canadian Securities Laws have been obtained to qualify the
               Distribution of the Over-Allotment Option



                                     - 26 -


               and the Securities in each of the Canadian Qualifying
               Jurisdictions through investment dealers or brokers duly
               registered under the Canadian Securities Laws of each such
               Canadian Qualifying Jurisdiction who have complied with the
               relevant provisions of the Canadian Securities Laws of such
               Canadian Qualifying Jurisdiction;

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

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

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

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

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



                                     - 27 -



               (other than registered education savings plans), registered
               pension plans and other tax exempt entities;

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

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

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

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

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

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

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

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

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



                                     - 28 -


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

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

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

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

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

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



                                     - 29 -



               materially affect the ability of the Company to conduct its
               business as described in the Registration Statement and
               Prospectus;

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

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

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

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

                    (i)  the statements contained in the Registration Statement
               and Prospectus under the captions "Risk Factors - Even if we
               complete MIRA-1, we may not receive FDA approval to market the
               RHEO System in the United States," "Risk Factors - If we fail to
               comply with the extensive regulatory requirements to which we and
               our RHEO System are subject, our RHEO System could be subject to
               restrictions or withdrawals from the market and we could be
               subject to penalties" and "Business - Government Regulation,"
               (collectively, the "FDA Portion") insofar as such statements
               purport to summarize applicable provisions of the Federal Food,
               Drug, and Cosmetic Act, as amended (the "FFDCA"), and the
               regulations promulgated thereunder, are accurate summaries in all
               material respects of the provisions of the FFDCA and the
               regulations thereunder purported to be summarized under such
               captions in the Registration Statement and the Prospectus; and

                    (ii)  based on such counsel's participation in the
               preparation of the FDA Portion, such counsel has no reason to
               believe that the information contained in the FDA Portion of the
               Registration Statement, as of the Effective Date, and in the FDA
               Portion of the Prospectus, as of its date, contained any untrue
               statement of a material fact or omitted to state any material
               fact necessary to make the statements



                                     - 30 -



               therein, in the light of the circumstances under which they were
               made, not misleading.

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

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

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

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

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

                    (iv)  neither the sale of the Securities being sold by any
               Selling Stockholder nor the consummation of any other of the
               transactions herein contemplated by any Selling Stockholder or
               the fulfillment of the terms hereof by any Selling Stockholder
               will conflict with, result in a breach or violation of, or
               constitute a default under any law or, with respect to TLC



                                     - 31 -



               only, the terms of any indenture or other agreement or instrument
               filed as an exhibit to TLC's 2003 Form 10-K, or any judgment,
               order or decree known to such counsel to be applicable to any
               Selling Stockholder or any of its subsidiaries of any court,
               regulatory body, administrative agency, Governmental Authority or
               arbitrator having jurisdiction over any Selling Stockholder or
               any of its subsidiaries.

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

               (h)  Diamed Medizintechnik GmbH ("Diamed") shall have requested
     and caused [ ], German counsel for Diamed, to have furnished to the
     Representatives their opinion, dated the Closing Date and addressed to the
     Representatives, to the effect that:

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

                    (ii)  no consent, approval, authorization or order of any
               German court or governmental agency or body is required for the
               consummation by Diamed of the transactions contemplated herein;
               and

                    (iii) neither the sale of the Securities being sold by
               Diamed nor the consummation of any other of the transactions
               herein contemplated by Diamed or the fulfillment of the terms
               hereof by Diamed will conflict with, result in a breach or
               violation of, or constitute a default under any German law or the
               organizational documents of Diamed or the terms of any indenture
               or other agreement or instrument known to such counsel and to
               which Diamed or any of its subsidiaries is a party or bound, or
               any judgment, order or decree known to such counsel to be
               applicable to Diamed or any of its subsidiaries of any German
               court, regulatory body, administrative agency, governmental body
               or arbitrator having jurisdiction over Diamed or any of its
               subsidiaries.



                                     - 32 -



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

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

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

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

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

                    (iv)  no consent, approval, authorization or order of any
               court or governmental agency or body of the Province of New
               Brunswick or of Canada is required in connection with the
               consummation by TLC of the transactions contemplated herein;

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

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



                                     - 33 -


               is such opinion) who have complied with the relevant provisions
               of such applicable Securities Laws.

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

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

               (k)  The Company shall have furnished to the Representatives
     certificates dated the Closing Date, signed by appropriate officers of the
     Company, addressed to the Underwriters and their counsel, with respect to
     the charter and by-laws of the Company, all resolutions of the board of
     directors of the Company and other corporate action relating to this
     Agreement and to the authorization, issue and sale of the Securities, the
     incumbency and specimen signatures of signing officers and with respect to
     such other matters as the Underwriters may reasonably request;

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

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

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

                    (iii) no order, ruling or determination having the effect of
               suspending the sale or ceasing the trading of the Securities or
               any other securities of the Company has been issued or made by
               any Governmental



                                     - 34 -


               Authority and is continuing in effect and no proceedings for that
               purpose have been instituted or are pending or, to the knowledge
               of the Company, contemplated or threatened by any Governmental
               Authority;

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

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

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

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

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



                                     - 35 -



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

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

                         (2)  with respect to the period subsequent to September
                    30, 2004, there were any changes, at a specified date not
                    more than two days prior to the date of the letter, in the
                    capital stock of the Company or partners' capital of
                    OccuLogix, L.P., increases in due to stockholders,
                    convertible debentures due to stockholders and long-term
                    convertible debentures of the Company and its subsidiaries
                    or increases in due to related parties of OccuLogix, L.P. or
                    increases in net current liabilities or stockholders'
                    deficiency of the Company or increases in net current
                    liabilities or partners' deficit of OccuLogix, L.P. as
                    compared with the amounts shown on the September 30, 2004
                    consolidated balance sheet of the Company and the September
                    30, 2004 balance sheet of OccuLogix, L.P., as applicable,
                    included in the Registration Statement and the Prospectus,
                    or for the period from October 1, 2004 to such specified
                    date there were any decreases, as compared with the
                    corresponding period in the preceding year, in revenues or
                    increases, as compared with the corresponding period in the



                                     - 36 -



                    preceding year, in total or per share amounts of net loss
                    for the period of the Company and its subsidiaries and
                    OccuLogix, L.P., except in all instances for changes,
                    decreases or increases set forth in such letter, in which
                    case the letter shall be accompanied by an explanation by
                    the Company or OccuLogix, L.P., as applicable, as to the
                    significance thereof unless said explanation is not deemed
                    necessary by the Underwriters; and

                         (3)  the information included in the Registration
                    Statement and the Prospectus in response to Regulation S-K,
                    Item 301 (Selected Financial Data) and Item 402 (Executive
                    Compensation), is not in conformity with the applicable
                    disclosure requirements of Regulation S-K;

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

                    (iv)  on the basis of a reading of the unaudited pro forma
               financial statements included in the Registration Statement and
               the Prospectus (the "pro forma financial statements"); carrying
               out certain specified procedures; inquiries of certain officials
               of the Company and OccuLogix, L.P. who have responsibility for
               financial and accounting matters; and proving the arithmetic
               accuracy of the application of the pro forma adjustments to the
               historical amounts in the pro forma financial statements, nothing
               came to their attention which caused them to believe that the pro
               forma financial statements do not comply as to form in all
               material respects with the applicable accounting requirements of
               Rule 11-02 of Regulation S-X or the Canadian Securities Laws or
               that the pro forma adjustments have not been properly applied to
               the historical amounts in the compilation of such statements.

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

               (o)  The Company shall have furnished to the Underwriters letters
     of its chief financial officer, at the Execution Time and at the Closing
     Date, dated respectively as of the Execution Time and as of the Closing
     Date, in form and substance reasonably



                                     - 37 -



     satisfactory to the Representatives, stating his conclusions and findings
     with respect to financial information contained in the Prospectus and not
     otherwise covered by the letters described in Section 6(n) hereof.

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

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

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

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

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

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

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



                                     - 38 -



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

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

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

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

     7.   Reimbursement of Underwriters' Expenses. If the sale of the Securities
provided for herein is not consummated because any condition to the obligations
of the Underwriters set forth in Section 6 hereof is not satisfied, because of
any termination pursuant to Section 10 hereof or because of any refusal,
inability or failure on the part of the Company or any Selling Stockholders to
perform any agreement herein or comply with any provision hereof other than by
reason of a default by any of the Underwriters, the Company will reimburse the
Underwriters severally through Citigroup Global Markets Inc. on demand for all
out-of-pocket expenses (including reasonable fees and disbursements of counsel)
that shall have been incurred by them in connection with the proposed purchase
and sale of the Securities. If the Company is required to make any payments to
the Underwriters under this Section 7 because of any Selling Stockholder's
refusal, inability or failure to satisfy any condition to the obligations of the
Underwriters set forth in Section 6, the Selling Stockholders pro rata in
proportion to the percentage of Securities to be sold by each shall reimburse
the Company on demand for all amounts so paid.

     8.   Indemnification and Contribution.

               (a)  The Company and each of the Major Selling Stockholders
     jointly and severally agree to indemnify and hold harmless each
     Underwriter, the directors, officers, employees and agents of each
     Underwriter and each person who controls any Underwriter within the meaning
     of either the Act or the Exchange Act against any and all



                                     - 39 -



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

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

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



                                     - 40 -


     sentences related to concessions and reallowances and (iii) the paragraph
     related to stabilization, syndicate covering transactions and penalty bids
     in any Preliminary Prospectus and the Prospectus constitute the only
     information furnished in writing by or on behalf of the several
     Underwriters for inclusion in any Preliminary Prospectus or the Prospectus.

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

               (e)  Promptly after receipt by an indemnified party under this
     Section 8 of notice of the commencement of any action, such indemnified
     party will, if a claim in respect thereof is to be made against the
     indemnifying party under this Section 8, notify the indemnifying party in
     writing of the commencement thereof; but the failure so to notify the
     indemnifying party (i) will not relieve it from liability under paragraph
     (a), (b) (c) or (d) above unless and to the extent it did not otherwise
     learn of such action and such failure results in the forfeiture by the
     indemnifying party of substantial rights and defenses and (ii) will not, in
     any event, relieve the indemnifying party from any obligations to any
     indemnified party other than the indemnification obligation provided in
     paragraph (a), (b), (c) or (d) above. The indemnifying party shall be
     entitled to appoint counsel of the indemnifying party's choice at the
     indemnifying party's expense to represent the indemnified party in any
     action for which indemnification is sought (in which case the indemnifying
     party shall not thereafter be responsible for the fees and expenses of any
     separate counsel retained by the indemnified party or parties except as set
     forth below); provided, however, that such counsel shall be reasonably
     satisfactory to the indemnified party. Notwithstanding the indemnifying
     party's election to appoint counsel to represent the indemnified party in
     an action, the indemnified party shall have



                                     - 41 -



     the right to employ separate counsel (including local counsel), and the
     indemnifying party shall bear the reasonable fees, costs and expenses of
     such separate counsel if (i) the use of counsel chosen by the indemnifying
     party to represent the indemnified party would present such counsel with a
     conflict of interest, (ii) the actual or potential defendants in, or
     targets of, any such action include both the indemnified party and the
     indemnifying party and the indemnified party shall have reasonably
     concluded based on advice of counsel that there may be legal defenses
     available to it and/or other indemnified parties which are different from
     or additional to those available to the indemnifying party, (iii) the
     indemnifying party shall not have employed counsel reasonably satisfactory
     to the indemnified party to represent the indemnified party within a
     reasonable time after notice of the institution of such action or (iv) the
     indemnifying party shall authorize the indemnified party to employ separate
     counsel at the expense of the indemnifying party. An indemnifying party
     will not, without the prior written consent of the indemnified parties,
     settle or compromise or consent to the entry of any judgment with respect
     to any pending or threatened claim, action, suit or proceeding in respect
     of which indemnification or contribution may be sought hereunder (whether
     or not the indemnified parties are actual or potential parties to such
     claim or action) unless such settlement, compromise or consent includes an
     unconditional release of each indemnified party from all liability arising
     out of such claim, action, suit or proceeding. It is understood that the
     indemnifying party shall not, in connection with any proceeding or related
     proceedings in the same jurisdiction, be liable for the reasonable fees and
     expenses of more than one separate firm for all such indemnified parties.
     Such firm shall be designated in writing by the Representatives in the case
     of parties indemnified pursuant to paragraph (a) or (d) and by the Company
     in the case of parties indemnified pursuant to paragraph (b) or (c). The
     indemnifying party shall not be liable for any settlement of any proceeding
     effected without its written consent but if settled with such consent or if
     there be a final judgment for the plaintiff, the indemnifying party agrees
     to indemnify the indemnified party from and against any loss or liability
     by reason of such settlement or judgment.

     Notwithstanding anything contained herein to the contrary, if indemnity may
     be sought pursuant to Section 8(d) hereof in respect of such action or
     proceeding, then in addition to such separate firm for the indemnified
     parties, the indemnifying party shall be liable for the reasonable fees and
     expenses of not more than one separate firm (in addition to any local
     counsel) for Citigroup Global Markets Inc., the directors, officers,
     employees and agents of Citigroup Global Markets Inc., and all persons, if
     any, who control Citigroup Global Markets Inc. within the meaning of either
     the Act or the Exchange Act for the defense of any losses, claims, damages
     and liabilities arising out of the Directed Share Program.

               (f)  In the event that the indemnity provided in paragraph (a),
     (b) (c) or (d) of this Section 8 is unavailable to or insufficient to hold
     harmless an indemnified party for any reason, the Company and the Major
     Selling Stockholders, jointly and severally, the Other Selling Stockholders
     severally and the Underwriters severally agree to contribute to the
     aggregate losses, claims, damages and liabilities (including legal or other
     expenses reasonably incurred in connection with investigating or defending
     same) (collectively "Losses") to which the Company, the Major Selling
     Stockholders, the Other Selling Stockholders and one or more of the
     Underwriters may be subject in such



                                     - 42 -



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

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



                                     - 43 -



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

     10.  Termination. This Agreement shall be subject to termination in the
absolute discretion of the Representatives, by notice given to the Company prior
to delivery of and payment for the Securities, if at any time prior to such time
(i) (x) trading in the Company's Common Stock shall have been suspended by the
Commission, any of the Canadian Securities Commissions, the Nasdaq National
Market or the TSX or trading in securities generally on the New York Stock
Exchange, the Nasdaq National Market or (y) the TSX shall have been suspended or
limited or minimum prices shall have been established on such Exchange, the
Nasdaq National Market or the TSX, (ii) a banking moratorium shall have been
declared either by Federal, New York State or Canadian authorities, (iii) there
shall have occurred any outbreak or escalation of hostilities, declaration by
the United States or Canada of a national emergency or war, or other calamity or
crisis the effect of which on financial markets is such as to make it, in the
sole judgment of the Representatives, impractical or inadvisable to proceed with
the offering or delivery of the Securities as contemplated by the Prospectus
(exclusive of any supplement thereto), (iv) any inquiry, action, suit,
investigation or other proceeding (whether formal or informal) is instituted,
announced or threatened or any order is made by any Governmental Authority
(other than an inquiry, action, suit, investigation or proceeding or order based
solely upon the activities or alleged activities of the Underwriters or the
Selling Firms), or there is any change of Law, or interpretation or
administration thereof, which, in the opinion of the Representatives, in
consultation with counsel, operates to prevent or restrict the Distribution or
offering of the Securities in the United States or any of the Canadian
Qualifying Jurisdictions or would prevent or restrict trading in the Securities
of the Company or would reasonably be expected to have a significant adverse
effect on the market price or value of the Securities or (v) the state of the
financial markets in Canada or the United States is such that, in the reasonable
opinion of the Representatives, the Securities cannot be profitably marketed.



                                     - 44 -



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

     12.  Notices. All communications hereunder will be in writing and effective
only on receipt, and, if sent to the Representatives, will be mailed, delivered
or telefaxed to the Citigroup Global Markets Inc. General Counsel (fax no.:
(212) 816-7912) and confirmed to Citigroup Global Markets Inc., at 388 Greenwich
Street, New York, New York 10013, Attention: General Counsel; or, if sent to the
Company, will be mailed, delivered or telefaxed to OccuLogix, Inc., 5280 Solar
Drive, Suite 100, Mississauga, Ontario L4W 5M8, Attention: Chief Executive
Officer (fax no.: (905) 602-7956); or if sent to any Selling Stockholder, will
be mailed, delivered or telefaxed and confirmed to it at the address set forth
in Schedule II hereto.

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

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

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

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

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

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

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

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



                                     - 45 -


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

               "Commission" shall mean the Securities and Exchange Commission.

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

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

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

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

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

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

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



                                     - 46 -



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

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

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

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

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

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

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

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

               "TSX" means the Toronto Stock Exchange.

               "U.S. Prospectus" shall mean the prospectus relating to the
     Securities that is first filed pursuant to Rule 424(b) after the Execution
     Time or, if no filing pursuant to Rule 424(b) is required, shall mean the
     form of final prospectus relating to the Securities included in the
     Registration Statement at the Effective Date.



                                     - 47 -





                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]






                                     - 48 -


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



                                    Very truly yours,

                                    OCCULOGIX, INC.


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


                                    [SELLING STOCKHOLDERS]


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






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

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


By:   Citigroup Global Markets Inc.


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


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




                                   SCHEDULE I



                                                              NUMBER OF UNDERWRITTEN
UNDERWRITERS                                                SECURITIES TO BE PURCHASED
- ------------                                                --------------------------
                                                         
Citigroup Global Markets Inc...............................
SG Cowen & Co., LLC........................................
ThinkEquity Partners LLC...................................
Orion Securities (USA) Inc.................................
DeMatteo Monness LLC.......................................
Citigroup Global Markets Canada Inc........................
Clarus Securities Inc......................................
Orion Securities Inc.......................................
Octagon Capital Corporation................................



                                                                  ----------------
                          TOTAL............................
                                                                  ================




                                   SCHEDULE II




                                        NUMBER OF UNDERWRITTEN    MAXIMUM NUMBER OF OPTION
     MAJOR SELLING STOCKHOLDERS         SECURITIES TO BE SOLD      SECURITIES TO BE SOLD
     --------------------------         ----------------------    ------------------------
                                                             
TLC Vision Corporation
[Address, Fax No.]..................

Diamed Medizintechnik GmbH
[Address, Fax No.]..................

Hans K. Stock
[Address, Fax No.]..................

Richard Davis
[Address, Fax No.]..................

John Cornish
[Address, Fax No.]..................







                                         NUMBER OF UNDERWRITTEN   MAXIMUM NUMBER OF OPTION
   OTHER SELLING STOCKHOLDERS            SECURITIES TO BE SOLD     SECURITIES TO BE SOLD
   --------------------------            ----------------------   ------------------------
                                                             
[Name]
[Address, Fax No.]..................




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

 





                                                                         ANNEX A


                            SIGNIFICANT SUBSIDIARIES










[FORM OF LOCK-UP AGREEMENT]                                            EXHIBIT A


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


                                 OccuLogix, Inc.
                         Public Offering of Common Stock

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

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


Ladies and Gentlemen:

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

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

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



                                     - 2 -



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

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




                                         Yours very truly,



                                         [SIGNATURE OF OFFICER, DIRECTOR OR
                                         MAJOR STOCKHOLDER]



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