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Exhibit 10.27

                AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER
                  AND AMENDMENT NO. 1 TO REVOLVING CREDIT LINE
                         AND REVOLVING PROMISSORY NOTE



     This Amendment No. 1 to the Agreement and Plan of Merger and Amendment No.
1 to Revolving Credit Line and Revolving Promissory Note dated as of October 1,
1998 (the "Merger Agreement") is entered into this 16th day of March, 1999, by
and among Autonomous Technologies Corporation ("Autonomous"), Summit Technology,
Inc. ("Summit") and Alpine Acquisition Corp. ("Alpine").  Capitalized terms used
herein and not otherwise defined shall have the same meaning as in the Merger
Agreement.

     WHEREAS, pursuant to notice duly given on February 17, 1999, Summit
extended the termination date of the Merger Agreement to March 30, 1999 and
agreed to increase the line of credit to Autonomous under the revolving credit
line to $6.5 million; and

     WHEREAS, the parties now desire to, among other things, extend the
termination date of the Merger Agreement to April 30, 1999.

     NOW THEREFORE, pursuant to Section 8.4 of the Merger Agreement, the parties
hereby agree to amend the Merger Agreement as follows:

     1.   Article VII of the Merger Agreement shall be amended by replacing the
          reference to February 28, 1999 with April 30, 1999.

     2.   The last paragraph of Section 7.1 shall be deleted in its entirety.

     3.   In connection with the execution of this Amendment, Summit and
          Autonomous hereby amend the Revolving Credit Line letter agreement,
          dated October 1, 1998, such that all references to $5,000,000 within
          such Revolving Credit Line letter are hereby replaced with $8,000,000.
          Further, Summit and Autonomous hereby amend the Revolving Promissory
          Note made by Autonomous to Summit, dated October 1, 1998, such that
          the reference to "Five Million Dollars ($5,000,000)" in the first
          paragraph of that Note is hereby replaced with "Eight Million Dollars
          ($8,000,000)."

     4.   A new Section 1.6(g) shall be inserted into the Merger Agreement as
          follows:

          (g)  Assumption of Warrants.  At the Effective Time, each warrant to
               purchase Company Common stock (a "Warrant") shall represent the
               right to purchase and receive (in lieu of the Company Stock
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               purchasable and receivable upon exercise of the rights
               represented thereby), upon exercise of the Warrant, the Merger
               Consideration issued or payable with respect to or in exchange
               for a number of outstanding shares of Company Common Stock equal
               to the number of shares of Company Common Stock purchasable and
               receivable upon the exercise of such Warrant immediately before
               the Merger.  The provisions of each Warrant (including, without
               limitation, provisions for adjustment of the exercise price and
               the number of shares purchasable and receivable upon exercise of
               the Warrant) shall be applicable, as nearly as practicable, after
               the Merger in relation to the Merger Consideration deliverable
               upon exercise of the Warrant.  At or before the Effective Time,
               Summit shall execute such instruments of assumption as may be
               required by any Warrant.

     5.   Section 5.11 of the Merger Agreement is hereby amended in its entirety
          such that it reads as follows:

          "Upon reasonable notice from the other, Parent and the Company shall
          use their respective best efforts to cause Deloitte & Touche LLP, as
          auditor of the December 31, 1998 financial statements for each of the
          Parent and the Company, and the Company shall use its best efforts to
          cause Arthur Andersen LLP, as auditor of its December 31, 1996 and
          1997 financial statements, to deliver to Parent or the Company, as the
          case may be, a letter, dated within 2 business days of the Effective
          Date of the S-4 Registration Statement covering such matters as are
          requested by Parent or the Company and as are customarily addressed in
          accountant's "comfort" letters."

     6.   This Amendment may be executed in two or more counterparts, each of
          which shall be deemed an original but all of which together shall
          constitute one and the same instrument.  This Amendment may be
          executed by facsimile signature.

     7.   Except as amended hereby, the Merger Agreement the Revolving Credit
          Line letter agreement and the Revolving Promissory Note shall remain
          in full force and effect in accordance with their terms.

     IN WITNESS WHEREOF, the parties have executed this Amendment as of the date
first written above.


                                    SUMMIT TECHNOLOGY, INC.



                                    By: /s/ Robert J. Palmisano
                                        -----------------------
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                                      Name:
                                      Title:


                                    ALPINE ACQUISITION CORP.



                                    By: /s/ Robert J. Palmisano
                                        -----------------------
                                      Name:
                                      Title:


                                    AUTONOMOUS TECHNOLOGIES
                                    CORPORATION



                                    By: /s/ Randy W. Frey
                                        -----------------
                                      Name: Randy W. Frey
                                      Title: CEO