FOURTH AMENDMENT
TO AMENDED AND RESTATED CREDIT AGREEMENT

            THIS FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (the
"Amendment") is made and dated as of the 25th day of March, 2003 by and between
BANK OF THE WEST ("Lender") and MENTOR CORPORATION (the "Borrower") and amends
that certain Amended and Restated Credit Agreement dated as of October 25, 2000
(as amended by a First Amendment dated as of February 2, 2001, a Second
Amendment dated as of February 14, 2001, a Third Amendment dated as of December
14, 2001 and as further amended, modified or waived from time to time, the
"Agreement") between Lender and the Borrower.

RECITALS

                        A.        The Borrower has asked the Lender to extend
the Loan Maturity Date (as such term and all other capitalized terms used in but
not otherwise defined in this Amendment are defined in the Agreement).

                        B.         Lender has agreed to do so on the terms and
conditions contained in this Amendment.

                        NOW, THEREFORE, in consideration of the above Recitals
and for other good and valuable consideration, the receipt and adequacy of which
are hereby acknowledged, the parties hereby agree that, upon the satisfaction of
the conditions contained in Paragraph 2 below, the Agreement shall be amended as
set forth below:

AGREEMENT

1.         Amendment.  The definitions of "Loan Maturity Date" in Paragraph 1 of
the Agreement is amended to read as follows:

Loan Maturity Date shall mean the earlier of:  (a) September 15, 2004, as such
date may be extended from time to time in writing by the Borrower and Lender,
(b) the date Lender terminates its obligations to make further Loans pursuant to
Paragraph 8 below; or the date the Credit Limit is reduced to $0.00."

2.         Conditions to Effectiveness of Amendment.  As conditions precedent to
the effectiveness of this Amendment, (1) the Borrower and Lender shall have duly
executed and delivered this Amendment and (2) Lender shall have received such
other additional documentation as it may request in connection herewith.

3.         Representations and Warranties of the Borrower.  As an inducement to
Lender to enter into this Amendment, the Borrower represents and warrants to
Lender that:

3(a)      No Change.  Since the date of the financial statements most recently
delivered to Lender pursuant to the Agreement, there has been no material
adverse change in the business, operations, assets or financial or other
condition of the Borrower or the Borrower and the Guarantors taken as a whole or
the Borrower and its consolidated Subsidiaries taken as a whole.  Since such
date, the Borrower has not entered into, incurred or assumed any long-term debt,
mortgages, material leases or material oral or written commitments not disclosed
to Lender prior to the date of this Amendment. 

3(b)      Corporate Existence; Compliance with Law.  The Borrower and each
Guarantor (1) is duly organized, validly existing and in good standing as a
corporation under the laws of the state of its incorporation and is qualified to
do business in each jurisdiction where its ownership of property or conduct of
business requires such qualification and where failure to qualify would have a
material adverse effect on it or its property and/or business or on the ability
of the Borrower to pay or perform the Obligations, (2) has the corporate power
and authority and the legal right to own and operate its property and to conduct
business in the manner in which it does and proposes so to do, and (3) is in
compliance in all material respects with all Requirements Of Law and Contractual
Obligations. 

3(c)      Corporate Power; Authorization; Enforceable Obligations.  The Borrower
and each Guarantor has the corporate power and authority and the legal right to
execute, deliver and perform this Amendment, as amended hereby, to which it is a
party and has taken all necessary corporate action to authorize the execution,
delivery and performance of this Amendment and the Loan Documents.  This
Amendment has been duly executed and delivered on behalf of the Borrower and
each Guarantor and constitutes legal, valid and binding obligations of the
Borrower and each Guarantor enforceable against the Borrower and each Guarantor
in accordance with its terms, subject to the effect of applicable bankruptcy and
other similar laws affecting the rights of creditors generally and the effect of
equitable principles whether applied in an action at law or a suit in equity. 

3(d)      No Legal Bar.  The execution, delivery and performance of this
Amendment will not violate any Requirement Of Law or any Contractual Obligations
of the Borrower or create or result in the creation of any Lien on any assets of
the Borrower or any Guarantor. 

4.  Miscellaneous Provisions. 

4(a)      Entire Agreement.  This Amendment and the documents and agreements
referred to herein embody the entire agreement and understanding between the
parties hereto and supersede all prior agreements and understandings relating to
the subject matter hereof and thereof. 

4(b)      Survival.  All representations, warranties, covenants and agreements
herein contained on the part of the Borrower shall survive the termination of
this Amendment and the Agreement and shall be effective until the Obligations
are paid and performed in full or longer as expressly provided herein. 

4(c)      Governing Law.  This Amendment shall be governed by and construed in
accordance with the laws of the State of California, without giving effect to
choice of law rules. 

4(d)      Counterparts.  This Amendment may be executed in any number of
counterparts, all of which together shall constitute one agreement. 

4(e)      Expenses.  In accordance with Paragraph 6(g) of the Agreement, the
Borrower agrees to pay to Lender, on demand, all reasonable out-of-pocket
expenses (including fees and disbursements of counsel, including reasonable
allocated cost of inside counsel) of Lender incident to the preparation,
negotiation, and closing of this Amendment.

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
this __ day of March, 2003 but to be effective as of the date and year first
above written. 

 

MENTOR CORPORATION, a
Minnesota corporation,
as the Borrower

By:   /s/CHRISTOPHER J. CONWAY
       Christopher J. Conway, Chairman and Chief Executive Officer

By: /s/ADEL MICHAEL
     Adel Michael, Chief Financial Officer

MENTOR CORPORATION
5425 Hollister
Santa Barbara, CA   93111

 

BANK OF THE WEST, as Lender

By: /s/DAVID G. KRONEN
David G. Kronen, Regional Vice President

Bank of the West
1036 State Street
Santa Barbara, CA  93101