AMENDMENT NO. 1 TO
                               INPUT/OUTPUT, INC.
                              AMENDED AND RESTATED
                  1996 NON-EMPLOYEE DIRECTOR STOCK OPTION PLAN

         This Amendment No. 1 (the "Amendment") to the Input/Output, Inc.
Amended and Restated 1996 Non-Employee Director Stock Option Plan (the "Plan")
is effective as of the 13 day of September, 1999, and except as modified herein,
the terms of the Plan remain in full force and effect. Any terms not otherwise
defined herein have the meanings ascribed to them as set forth in the Plan.

                                    AMENDMENT

         The Plan is hereby amended by adding the following sentence to the end
of Section 4.6:

         "The Board (or the Compensation Committee of the Board), in its sole
discretion, may extend the period during which a Stock Option may be exercised;
provided, however, that no Nonqualified Stock Option shall be exercisable for a
period of longer than ten (10) years."


         IN WITNESS WHEREOF, the Board of Directors of Input/Output, Inc. has
caused this Amendment to the Plan to be adopted as of the date first written
above and has instructed the officer indicated below to sign same for and on
behalf of such corporation.

                                                     INPUT/OUTPUT, INC.


                                                     By: /s/ JAY LAPEYRE
                                                        -----------------------
                                                     Name: Jay Lapeyre
                                                          ---------------------
                                                     Title: Chairman
                                                           --------------------