Document:

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                                                                   EXHIBIT 10.43

CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
              EXCHANGE COMMISSION. ASTERISKS DENOTE SUCH OMISSIONS.

                               AMENDMENT NO. 1 TO
                            STOCK PURCHASE AGREEMENT

This Amendment No. 1 is made and entered into as of and effective on August 6,
2002, and amends the Stock Purchase Agreement dated as of February 19, 1998 (the
"Agreement"), by and between V.I. Technologies, Inc., a Delaware corporation
("Vitex"), and Pall Corporation, a New York corporation ("Pall").

WHEREAS, the parties hereto desire to amend the Agreement as set forth below,

NOW, THEREFORE, in consideration of the mutual covenants and agreements
hereinafter set forth, Vitex and Pall agree as follows:

     1.   Sections 1(e) and 2(e) of the Agreement are hereby deleted in their
entirety.

     2.   Section 2(d) of the Agreement is hereby amended and restated to read
in its entirety as follows:
                  "(d) The closing of the purchase and sale of the Shares
          pursuant to paragraph 1(d) of this Agreement (the "Fourth Closing")
          shall occur on such date as may be agreed upon by Pall and Vitex;
          provided that without the written consent of both Pall and Vitex, but
          subject to Section 6 of this Agreement, the Fourth Closing shall occur
          on the tenth business day after the date on which the System is first
          used by Vitex in a clinical investigation (as defined in 21 CFR
          ss.312.3) under the protocol for the Phase 3 study in the IND (the
          "Fourth Closing Trigger Date"), provided, however, that if the Fourth
          Closing Trigger Date does not occur by December 31, 2002, there shall
          be no Fourth Closing and both parties shall be relieved and released
          of and from their obligations under Sections 1(d) and 2(d) of this
          Agreement. At the Fourth Closing, if any, Pall shall pay Vitex $4
          million in immediately available funds to such account as Vitex shall
          designate, against delivery to Pall of a certificate for the number of
          shares determined under paragraph 1(d) of this Agreement."

     3.   Section 2(g) of the Agreement is hereby amended and restated to read
in its entirety as follows:
                 "(g)  The Initial Closing, the Second Closing, the Third
          Closing, the Fourth Closing (if any) and the IPO Closing are
          hereinafter referred to collectively as the "Closings" and
          individually as a "Closing." Each Closing other than the IPO Closing
          shall occur at the offices of Carter, Ledyard & Milburn, 2 Wall
          Street, New York, New York, or such other location as may be agreed
          upon by Vitex and Pall. The date on which any Closing occurs is
          referred to herein as a `Closing Date.'"

     4.   A new Section 5(i) of the Agreement is hereby added as follows:

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                 "(i)  Agreement Not to Dispose of Shares. Notwithstanding any
          provisions of this Agreement, the Registration Rights Agreement, the
          First Stockholders' Agreement or the Second Stockholders' Agreement to
          the contrary, Pall agrees that until after December 31, 2002, it will
          not, without the prior written consent of Vitex, sell, pledge, assign,
          transfer or otherwise dispose of any Shares. After December 31, 2002,
          Pall shall only dispose of Shares in an orderly manner designed not to
          disrupt the trading of Vitex's securities or the price thereof."

     5.   Section 8 of the Agreement is hereby amended and restated to read in
           its entirety as follows:
                 "8. Notices. All notices and other communications provided for
          or permitted hereunder shall be made in writing (a) by hand delivery
          or registered first class mail, postage prepaid, return receipt
          requested, or air courier guaranteeing overnight delivery, to the
          following addresses, or (b) by facsimile transmission or e-mail to the
          following numbers or e-mail addresses:

                      If to Pall:

                               Pall Corporation
                               2200 Northern Boulevard
                               East Hills, New York  11548
                               Attention: [*****]
                               Fax No.: [*****]
                               E-mail: [*****]

                      with a copy to:

                               Carter, Ledyard & Milburn
                               2 Wall Street
                               New York, New York  10005-2072
                               Attention [*****]
                               Fax No.: [*****]
                               E-mail: [*****]

                      If to Vitex:

                               V.I. Technologies, Inc.
                               134 Coolidge Avenue
                               Watertown, Massachusetts  02472
                               Attention: [*****]
                               Fax No.: [*****]
                               E-mail: [*****]

                      with a copy to:

                               Kaye Scholer LLP
                               425 Park Avenue
                               New York, New York  10022-3598
                               Attention: [*****]
                               Fax No.: [*****]
                               E-mail: [*****]

----------
Confidential materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote such omissions.

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                      All such notices and communications shall be deemed
                      to have been duly given and received on the date
                      delivered by hand or by facsimile transmission or
                      e-mail; five business days after being deposited in
                      the mail, postage prepaid, if mailed; and on the next
                      business day, if timely delivered to an air courier
                      guaranteeing overnight delivery. Either party may
                      change its address for notices by a notice to the
                      other party given in accordance with this section."

    6. In all other respects, the Agreement shall remain in full force and
       effect in accordance with its terms.

IN WITNESS WHEREOF, Vitex and Pall have each caused this Amendment No. 1 to be
executed by its duly authorized officer, each as of and effective on the date
first above written.

                           V.I. TECHNOLOGIES, INC.

                           By: /s/ John R. Barr
                               ----------------------
                               Print Name: John R. Barr
                               Title: President and Chief Executive Officer

                           PALL CORPORATION

                           By: /s/ Samuel T. Wortham
                               ----------------------
                               Print Name: Samuel T. Wortham
                               Title: Group Vice President

                                        3<PAGE>

                                                                   Exhibit 10.26

                           FOURTH AMENDED AND RESTATED
                              EMPLOYMENT AGREEMENT

     THIS AGREEMENT, entered into as of the 20th day of February, 2002, amends
and restates the Amended and Restated Agreement, dated as of the 20th day of
February, 2000, by and between KOPIN CORPORATION, a Delaware corporation with
its principal place of business at 695 Myles Standish Boulevard, Taunton MA
02780 (the "Employer"), and John C. C. Fan, an individual residing at XXXXXXXXXX
(the "Employee"), as first amended and restated as of May 1, 1995.

     (S)1. Freedom to Contract. The Employee represents that he is free to enter
into this Agreement, that he has not made and will not make any agreements in
conflict with this Agreement, and will not disclose to the Employer, or use for
the Employer's benefit, any trade secrets or confidential information now or
hereafter in the Employee's possession which is the property of any other party.

     (S)2. Employment. The Employer hereby employs the Employee, and the
Employee hereby accepts his employment by the Employer, upon the terms and
conditions set forth herein.

     (S)3. Effective Date and Term. This Agreement shall take effect as of
February 20, 2002 (the "Effective Date"), and shall continue thereafter in full
force and effect through February 20, 2004, unless terminated prior to such time
in accordance with the provisions of this Agreement.

     (S)4. Title and Duties; Extent of Services. The Employee shall promote the
business and affairs of the Employer as President and Chief Executive Officer of
the Employer, with responsibility for performing such duties consistent with
such position as the Board of Directors may from time to time designate. As long
as he is employed hereunder, the Employee shall also continue to serve, if
elected by the Shareholders, as a member of the Board of Directors of the
Employer.

     (S)5. Termination Rights of the Parties. The employment of the Employee by
the Employer under this Agreement may be terminated at any time by either the
Employee or Employer upon 360 days' prior written notice of such termination to
the other.

     (S)6. Compensation. Employee shall be paid a salary at an initial annual
rate of Four Hundred Thousand Dollars ($400,000) through December 31, 2002. The
Board of Directors, in its sole discretion, shall have the absolute right to
determine the Employee's salary and benefits for each subsequent fiscal year

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                                      -2-

during the term hereof, provided that in no event shall such salary and such
benefits be less than such initial annual rate and the benefits awarded to the
Employee during the initial year hereof. The Employer agrees to diligently
review and consider alternative means of providing the Employee with additional
tax advantaged compensation.

     (S)7. Inventions and Proprietary Information.

     (S)7.1. Inventions. Employee shall inform the Employer using the
established procedures promptly and fully of all inventions, improvements,
discoveries, know-how, designs, processes, formulae and techniques, and any
related suggestions and ideas (hereinafter "Inventions"), whether patentable or
not, which are solely or jointly conceived or made by Employee, during the
period of Employee's employment by the Employer, whether during or out of
Employee's usual hours of work. The Employer shall own all right, title and
interest to those inventions (hereinafter "Employer Inventions") which are: (a)
within the scope of the Employer's business, which includes areas in which
research is being conducted and areas of technical or market investigation;
and/or (b) related to work done for the Employer by Employee. Employee hereby
assigns and agrees to assign to the Employer Employee's entire right, title and
interest in all Employer Inventions and any patents, design patents, and any
other forms of intellectual property resulting therefrom. Employee shall protect
the Employer's right to patent Employee's Employer Inventions by keeping written
records, which are witnessed and dated, concerning dates of conception and
reduction to practice, and Employee shall not publish information concerning
Employer Inventions without prior approval from the Employer. Employee shall
also, during and after Employee's employment, execute such written instruments
and render such other assistance as the Employer shall reasonably request to
obtain and maintain patents, design patents, or other forms of protection on any
Employer Inventions and to vest and confirm in the Employer its entire right,
title and interest therein. In this regard, Employee shall be reimbursed by the
Employer for actual expenses incurred and, if no longer an employee of the
Employer, shall be reasonably compensated for assistance rendered.

     (S)7.2. Proprietary Information. (a) Employee understands that as a
consequence of Employee's employment by the Employer, proprietary data and
confidential information (both hereinafter referred to as "Information")
relating to the business of the Employer may be disclosed to Employee or
developed by Employee which is not generally known in the Employer's trade and
which is of considerable value to the Employer. Such Information includes,
without limitation, information about trade secrets, the Employer Inventions (as

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                                      -3-

previously defined), patents, licenses, research projects, costs, profits,
markets, sales, customer lists, plans for future development, and any other
information of a similar nature to the extent not generally known in the trade.
Employee acknowledges and agrees that Employee's relationship to the Employer
with respect to such Information shall be fiduciary in nature. Employee shall
not make any use of any such Information except in the performance of Employee's
work for the Employer; Employee shall maintain such Information in confidence;
and Employee shall not disclose to any person not employed by the Employer any
such Information at any time either during or after Employee's employment or use
any such Information in connection with other employment, except as authorized,
in writing, by a duly empowered officer of the Employer.

          (b) Employee shall deliver promptly to the Employer on termination of
Employee's employment, or at any time the Employer so requests, all memoranda,
notes, records, reports, manuals, drawings, blueprints, plans, customer lists,
pricing and/or cost data, and all other property or materials belonging to the
Employer, including all copies thereof, which Employee then possesses or has
under Employee's control.

          (c) Employee covenants that there are no Inventions and/or patents
within the scope of the Employer's business in which Employee held an interest
prior to the date of this Agreement and which are not subject to this Agreement.

  (S)7.3. Remedies. Employee recognizes that irreparable injury may result to
the Employer, its business and property, in the event of a breach of any of the
agreements, assurances and understandings contained herein. Employee further
recognizes that in the event of such a breach, or the substantial likelihood
that such a breach will occur, the Employer intends to take legal action, and to
seek injunctive relief if available, in accordance with the language and spirit
of this Agreement in order to protect fully its interests and property.

    (S)8. Covenant Not to Compete.

          (a) The Employee recognizes that the Employer is engaged in the
development and sale of III-IV compounds used in semiconductors and related
products in Massachusetts and throughout the United States and the world and in
the development of liquid crystal electronic imaging devices and display
products based thereon (collectively, the "Principal Business"). In the event of
the termination of the Employee's employment hereunder, voluntarily or for cause
(as defined in Section 8(d) below) and so long as the Employer is not in breach
of its obligations to the Employee hereunder, the Employee agrees

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                                      -4-

that, for a period of twelve (12) months from the date of such termination, he
will neither

          (i)  engage in the Principal Business directly for himself, or in
               conjunction with or on behalf of any commercial entity, or

          (ii) work as an employee in the Principal Business for any commercial
               entity,

where either (A) the Employee's duties in the course of any such activities
would be substantially similar to those he has performed for the Employer
hereunder or (B) the Employee's duties in the course of such activities would
involve disclosure or use of any confidential or proprietary information
relating to the business of the Employer which he may in any way acquire by
reason of his employment by the Employer. The Employee's obligation under this
Section 8 shall extend to all geographical areas of the United States and the
world in which the Employer, as set forth above, carries on business, either
directly or indirectly, including, but not limited to, places where the Employer
has a place of business, has employees or representatives, or has advertised or
sold any products during the time period specified in this section.

          (b) The Employee further agrees that for a period of twelve (12)
months from the date of such termination, he will not on behalf of himself or
any commercial competitor of the Employer, compete for, or engage in the
solicitation of, with respect to the Company's products or services, any
commercial customer of the Employer, that he has, during the one year
immediately preceding such termination, solicited or serviced on behalf of the
Employer or that has been so solicited or serviced, during such period, by any
person under the Employee's supervision.

          (c) In the event of any violation of the foregoing provisions of this
Section 8, the Employer shall be entitled, in addition to any other rights or
remedies it may have, to injunctive relief, it being agreed that the damages
which the Employer would sustain upon any such violation are difficult or
impossible to ascertain in advance and that the Employee's violations may cause
irreparable harm to the Employer.

          (d) The term "cause" shall mean termination due to an act or acts by
the Employee in willful contravention of the written directions of the Board of
Directors of the Employer.

    (S)9. Provisions of General Application.

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                                      -5-

     (S)9.1. Governing Law. This Agreement and the rights and obligations of the
parties hereunder shall be construed, interpreted and determined in accordance
with the laws of the Commonwealth of Massachusetts.

     (S)9.2. Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be an original and all of which, taken
together, shall constitute one and the same instrument. In making proof of this
Agreement it shall not be necessary to produce or account for more than one such
counterpart.

     (S)9.3. Other Agreements. This Agreement represents the entire
understanding and agreement between the parties as to the subject matter hereof.
No prior, concurrent or subsequent agreement, whether written or oral, shall be
construed to change, amend, alter, repeal or invalidate this Agreement, unless
this Agreement is specifically identified in and made subject to such other
written agreement.

     (S)9.4. Amendment. This Agreement may be amended only by a written
instrument executed in one or more counterparts by the parties hereto.

     (S)9.5. Waiver. No consent to or waiver of any breach or default in the
performance of any obligation hereunder shall be deemed or construed to be a
consent to or waiver of any other breach or default in the performance of any of
the same or any other obligation hereunder. Failure on the part of either party
to complain of any act or failure to act of the other party or to declare the
other party in default, irrespective of the duration of such failure, shall not
constitute a waiver or rights hereunder and no waiver hereunder shall be
effective unless it is in writing, executed by the party waiving the breach or
default hereunder.

     (S)9.6. Headings. The headings of sections and subsections of this
Agreement have been inserted for convenience of reference only and shall not be
deemed to be a part of this Agreement or to affect the meaning of any of its
provisions.

     (S)9.7. Severability. If any provision of this Agreement shall, in whole or
in part, prove to be invalid for any reason, such invalidity shall affect only
the portion of such provision which shall be invalid, and in all other respects
this Agreement shall stand as if such invalid provision, or the invalid portion
thereof, had not been a part hereof.

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                                      -6-

     (S)9.8. Notices and Other Communications. All notices and other
communications required hereunder shall be effective if in writing and if
delivered or sent by certified or registered mail, return receipt requested (a)
if to the Employee, at his residence address first set forth above, and (b) if
to the Employer, at 695 Myles Standish Boulevard, Taunton MA, Attention: Chief
Financial Officer, with a copy to John H. Chu, Esq., Chu, Ring & Hazel LLP, 49
Melcher Street, Boston, Massachusetts 02210, or to such other persons or
addresses as the parties hereto may specify by a written notice to the other
from time to time.

     IN WITNESS WHEREOF, this Agreement has been executed by the Employer, by
its duly authorized officer, and by the Employee, as of the date first above
written.

KOPIN CORPORATION

By: /s/ Richard A. Sneider                          /s/ John C. C. Fan
   ---------------------------------             -------------------------
     Richard A. Sneider                                John C. C. Fan
     Chief Financial Officer
       and Treasurer

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