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                                                                EXHIBIT 8.1     
                     
                  [Ropes & Gray Letterhead Appears Here]     
                                             
                                               , 1999     
   
Summit Technology, Inc.     
   
21 Hickory Drive     
   
Waltham, MA 02451     
   
Ladies and Gentlemen:     
   
  We have acted as counsel to Summit Technology, Inc. ("Summit"), a
Massachusetts corporation, in connection with the planned transaction (the
"Merger") contemplated by the Agreement and Plan of Merger, dated as of October
1, 1998, by and among Summit, Alpine Acquisition Corp., a Delaware corporation
and a wholly-owned subsidiary of Summit ("Merger Sub"), and Autonomous
Technologies Corporation, a Florida corporation ("Autonomous") (the "Merger
Agreement"). All capitalized terms used but not defined herein have the
meanings ascribed to them in the Merger Agreement.     
   
  For purposes of the opinion set forth below, we have reviewed and relied upon
(i) the Merger Agreement, (ii) the Joint Proxy Statement and Prospectus
included in the Registration Statement on Form S-4 filed by Summit with the
Securities and Exchange Commission on January 7, 1999 (the "Proxy Statement"),
and (iii) such other documents, records and instruments as we have deemed
necessary or appropriate as a basis for our opinion. We have assumed without
investigation or verification that all statements contained in the foregoing
documents are true, correct, and complete as of the date hereof and will remain
true, correct and complete through the Effective Time; that no actions
inconsistent with such statements have occurred or will occur; that all such
statements made "to the best of the knowledge of" any persons or parties, or
similarly qualified, are true, correct and complete as if made without such
qualification; and, as to all matters in which a person or entity making a
representation has represented that such person or entity either is not a party
to, does not have, or is not aware of, any plan or intention, understanding or
agreement, we have assumed that there is in fact no such plan, intention,
understanding or agreement.     
   
  We also have assumed that (i) the Merger will be consummated in accordance
with the Merger Agreement (including satisfaction of all covenants and
conditions to the obligations of the parties without amendment or waiver
thereof); (ii) all representations and warranties contained in the Merger
Agreement are true, correct, and complete in all respects; (iii) the Merger
will be effective as a merger under the applicable laws of Delaware and
Massachusetts; and (iv) if the Merger is not restructured as a fully taxable
Merger, (a) each of Summit, Autonomous and Merger Sub will deliver a tax
representation certificate satisfactory to Ropes & Gray and (b) each of Summit,
Autonomous and Merger Sub will comply with the reporting obligations with
respect to the Merger, if any, required under the Internal Revenue Code (the
"Code") and the Treasury regulations promulgated thereunder.     
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Summit Technology, Inc.                   -2 -                      , 1999     
   
  Any inaccuracy in, or breach of, any of the aforementioned statements,
representations and assumptions and any change in applicable law after the date
hereof could adversely affect our opinion. No ruling has been sought from the
Internal Revenue Service by Summit, Autonomous or Merger Sub as to the federal
income tax consequences of any aspect of the Merger, and the Internal Revenue
Service is not bound by our opinion herein.     
   
  Based upon and subject to the foregoing as well as to the qualifications and
limitations set forth below, it is our opinion that the legal conclusions under
the caption "Material Federal Income Tax Consequences of the Merger" in the
Proxy Statement constitute the opinion of Ropes & Gray as to the material
United States federal income tax consequences generally applicable to
Autonomous stockholders in connection with the Merger.     
   
  No opinion is expressed as to any matter not specifically addressed above,
including the tax consequences of any of the transactions under any foreign,
state, or local tax law or the tax consequences of any other transactions
contemplated or entered into by Summit, Autonomous or Merger Sub in connection
with the transactions described above. Our opinion is based on current federal
income tax law and we do not undertake to advise you as to any changes in
federal income tax law after the date hereof that may affect our opinion.     
   
  This opinion is solely for your benefit, shall not inure to the benefit of
any other person, including without limitation any successor or assign of
Summit, whether by operation of law or otherwise, and is not to be used,
circulated, quoted or otherwise referred to for any purpose without our express
written permission.     
   
  We hereby consent to the filing with the Securities and Exchange Commission
of this opinion as an exhibit to the Proxy Statement.     
                                             
                                          Very truly yours,     
                                             
                                          Ropes & Gray