Page ---- EXHIBIT A Agreement of Reporting Persons 18

 
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EXHIBIT A           Agreement of Reporting Persons      18

 
                                   Exhibit A
                                   ---------

     Each of the undersigned hereby agrees that Amendment No. 1 to the Schedule
13G filed on the date hereof with respect to the shares of Common Stock of
Keravision, Inc. has been filed on behalf of the undersigned.

Signature:
----------


     Dated February 13, 1997


                              Oak Investment Partners V,
                              Limited Partnership

                              By:   Oak Associates V,
                                    Limited Partnership,
                                    As General Partner


                              By:   /s/ Xxxxxx X. Xxxxxxxxxx
                                    -------------------------------
                                    General Partner

                              Oak Associates V, Limited Partnership


                              By:   /s/ Xxxxxx X. Xxxxxxxxxx
                                    --------------------------------            
                                    General Partner


                              Oak V Affiliates Fund, Limited Partnership
 
                              By:   Oak V Affiliates,
                                    As General Partner


                              By:   /s/ Xxxxxx X. Xxxxxxxxxx
                                    -------------------------------
                                    General Partner


                              Oak V Affiliates


                              By:   /s/ Xxxxxx X. Xxxxxxxxxx
                                    -------------------------------
                                    General Partner

 
                              OAK MANAGEMENT CORPORATION



                         By:  /s/ Xxxxxx X. Xxxxxxxxxx
                              -------------------------------------          
                              Name:  Xxxxxx X. Xxxxxxxxxx
                              Title: President



                              /s/ Xxxxxx X. Xxxxxx
                              ------------------------------------
                              Xxxxxx X. Xxxxxx



                              /s/ Xxxxxxx X. Xxxxxx
                              ------------------------------------
                              Xxxxxxx X. Xxxxxx



                              /s/ Xxxxxx X. Xxxxxxxxx
                              ------------------------------------
                              Xxxxxx X. Xxxxxxxxx



                              /s/ Xxxxxx X. Xxxxxxxxxx
                              ------------------------------------
                              Xxxxxx X. Xxxxxxxxxx



                              /s/ Xxx X. Xxxxxx
                              ------------------------------------
                              Xxx X. Xxxxxx



                              /s/ Xxxxxx X. More
                              ------------------------------------
                              Xxxxxx X. More