<PAGE>   1

                                                                 EXHIBIT 10.3(c)



                                 AMENDMENT NO. 1

                                       TO

                            PATENT LICENSE AGREEMENT


        THIS AMENDMENT TO PATENT LICENSE AGREEMENT (this "Amendment") is dated
as of February 20, 2000 ("Effective Date") and is by and between International
Remote Imaging Systems, Inc., a Delaware corporation ("IRIS"), and Sysmex
Corporation, a Japanese corporation ("SYSMEX") formerly named TOA Medical
Electronics Co., Ltd., ("TOA"), with respect to the following facts:

        A. IRIS and TOA entered into that certain Patent License Agreement dated
as of April 1, 1997 (the "Patent License Agreement"), pursuant to which IRIS
licensed to TOA certain IRIS' patents for use by TOA in the development,
manufacturing, marketing, distribution and sale, on a commercial basis, of
instruments for non-medical, industrial applications in Japan and for certain
Japanese customers outside of Japan.

        B. IRIS now desires to license to SYSMEX, and SYSMEX now desires to
license from IRIS, such patents for use worldwide, subject to the terms and
conditions of the Patent License Agreement, as amended by this Amendment No. 1.

        NOW, THEREFORE, in consideration of the mutual covenants, promises,
agreements set forth in this Amendment, and for other good valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties amend the Patent License Agreement as follows. Unless otherwise stated,
all capitalized terms shall have the same meanings assigned to them in the
Patent License Agreement.

        1. Section 2 of the Patent License Agreement shall be renumbered as
Section 2(a).

        2. The following shall be added as Section 2(b) of the Patent License
Agreement:

               "In consideration of the payments by TOA to IRIS pursuant to
Sections 5.1, IRIS hereby grants to TOA for the Term a non-exclusive right and
license under the IRIS Patents to practice inventions covered by the IRIS
Patents to make Sales of Industrial Products worldwide, other than Sales as to
which a license is granted pursuant to Section 2(a) herein. Sales of Industrial
Products may be made directly by TOA or indirectly through a distributor or
agent of TOA. IRIS represents and warrants that it owns or holds rights to the
IRIS Patents necessary to grant the rights conveyed hereunder, and that the
exercise of such rights by TOA as contemplated hereunder will not conflict with,
infringe or otherwise violate the rights of third parties. This representation
is not intended to cover compliance with United States export laws affecting the
transfer of IRIS Patents, compliance with which TOA assumes responsibility."

        3. Section 5.1(b) of Patent License Agreement shall be amended to read
as follows:

               "b. Periodic Payment.

                      (i) With respect to the license granted under Section
2(a), not later than thirty (30) days following the end of each calendar quarter
throughout the Term, TOA shall pay to IRIS in immediately available funds in US
Dollars royalties in the amount of five percent (5%) of Revenues received by TOA
or its subsidiaries from sales of Industrial Products and Associated Consumable
and Spare Parts during such completed calendar quarter (the "Periodic
Payments"), net of payments made pursuant to Sections 5.1(c)(i).

                      (ii) With respect to the license granted under Section
2(b), not later than thirty (30) days following the end of such calendar quarter
throughout the Term, TOA shall pay to IRIS in



                                       7
<PAGE>   2

immediately available funds in US Dollars royalties in the amount of five
percent (5%) of Revenues received by TOA or its subsidiaries from Sales of
Industrial Products and Associated Consumable and Spare Parts during such
completed calendar quarter (the "Periodic Payments"), net of payments made
pursuant to Sections 5.1(c)(ii).

        4. Section 5.1(c) of the Patent License Agreement shall be amended to
read as follows:

               "c. Minimum Payments.

                      (i) With respect to the license granted under Section
2(a), for each of the three (3) 12-month periods commencing July 1, 1998, July
1, 1999 and July 1, 2000 only, TOA shall make minimum payments to IRIS in the
amount of Fifty Thousand US Dollars (US$50,000). Each such minimum payment shall
be payable at the commencement of each such twelve-month (12-month) period and
shall be credited against the payment of Periodic Payments due in respect to
Revenues received by TOA with respect to the license granted under Section 2(a)
during such 12-month period."

                      (ii) With respect to the license granted under Section
2(b), for each of the four (4) 12-month periods commencing July 1, 2000, July 1,
2001, July 1, 2002 and July 1, 2003 only, TOA shall make minimum payments to
IRIS in the amount of Fifth Thousand US Dollars (US$50,000). Each such minimum
payment shall be payable at the commencement of each such twelve-month
(12-month) period and shall be credited against the payment of Periodic Payments
due in respect to Revenues received by TOA with respect to the license granted
under Section 2(b) during such 12-month period."

        5. Within ten (10) business days after execution of this Amendment,
SYSMEX shall pay to IRIS, as an additional payment under Section 5.1(a) of the
Patent License Agreement, with respect to grant of the license pursuant to
Section 2(b) of the Patent License Agreement, the amount of Three Hundred
Thousand US Dollars (US$300,000).

        6. All other terms and conditions of the Patent License Agreement shall
remain in full force and effect.

        7. This Amendment may be executed in any number of counterparts, each of
which shall be deemed an original and all of which shall constitute one and the
same instrument.



INTERNATIONAL REMOTE                        SYSMEX CORPORATION,
SYSTEMS, INC.,                              a Japanese corporation
a Delaware Corporation

By:  /s/  John C. O'Malley                  By:  /s/  Kenichi Yukimoto
Name:     John C. O'Malley                  Name:     Kenichi Yukimoto
Title:    Chairman, CEO, & President        Title:    Senior Managing Director



                                       8