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                                                                    EXHIBIT 4.33

                                  July 21, 2000

Vision Twenty-One, Inc.
7360 Bryan Dairy Road, Suite 200
Largo, FL 33777
Attention:        Bruce Maller, Chairman of the Board

Gentlemen:

         We refer to the Amended and Restated Credit Agreement dated as of July
1, 1998, as amended, between you and us (the "Credit Agreement"). All
capitalized terms used herein without definition shall have the same meaning
herein as such terms are defined in the Credit Agreement.

         The Borrower has advised the Banks that the Borrower is currently
working on a revised business plan which will include, among other things, a
request to restructure the Obligations owing to the Banks on terms and
conditions mutually agreed upon by the Borrower and the Banks. While the
Borrower and the Banks have initiated discussions concerning the proposed
restructuring of the Obligations, the Borrower acknowledges that the Banks have
not agreed to any terms and conditions relating to any restructuring of the
Obligations. In the meantime, however, the Borrower intends to continue to sell
the remaining physician practice management groups operated by the Borrower and
its Subsidiaries (collectively being referred to herein as the "PPM Businesses")
and use a portion of the proceeds from the sale of the PPM Businesses to meet
its reasonable and necessary operating expenses.

         To afford the Borrower an opportunity to proceed with the transactions
described above, the Borrower has requested that (i) the Banks extend the
temporary waiver period provided for in Sections 2.1 and 2.2 of that certain
Seventh Amendment and Waiver to Credit Agreement dated as of December 10, 1999,
among the Borrower, the Banks, and the Agent (the "Seventh Amendment") (as
further amended, in part, by a December 30, 1999, letter agreement, a February
29, 2000, letter agreement, a March 24, 2000, letter agreement, an April 14,
2000, letter agreement, a May 5, 2000, letter agreement, a May 19, 2000, letter
agreement, a June 1, 2000, letter agreement, a June 9, 2000, letter agreement, a
June 16, 2000, letter agreement, and a June 29, 2000, letter agreement, in each
case between the Borrower, the Banks and the Agent) and, in addition, that the
Banks temporarily waive any non-compliance by the Borrower as of December 31,
1999, and as of March 31, 2000, with Sections 8.8 (Total Funded Debt/Adjusted
EBITDA Ratio), 8.10 (Interest Coverage Ratio), and 8.11 (Debt Service Coverage
Ratio) of the Credit Agreement and the Borrower's non-compliance with Section
8.5(b) of the Credit Agreement with respect to the timely delivery of the
Borrower's March 31, 2000, financial


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Vision Twenty-One, Inc.
July 21, 2000
Page 2

statements, in each case to August 11, 2000 (the "Waiver Termination Date"),
(ii) Bank of Montreal extend the Bridge Loan Period from July 21, 2000, to the
Waiver Termination Date, and (iii) amend the due date for the payment of
principal, interest and unused commitment fees otherwise due on or before July
31, 2000, with respect to the Revolving Credit and the Term Loans (including
such payments described in Sections 2.1 and 2.2 of the Seventh Amendment) to the
Waiver Termination Date. By signing below, the Banks (including Bank of Montreal
with respect to the Bridge Loan Commitment) hereby agree to extend the waiver
period provided in Sections 2.1 and 2.2 of the Seventh Amendment from July 21,
2000, to the Waiver Termination Date, temporarily waive any non-compliance by
the Borrower as of December 31, 1999, and March 31, 2000, with Sections 8.8
(Total Funded Debt/Adjusted EBITDA Ratio), 8.10 (Interest Coverage Ratio), and
8.11 (Debt Service Coverage Ratio) of the Credit Agreement and the Borrower's
non-compliance with Section 8.5(b) of the Credit Agreement with respect to the
timely delivery of the Borrower's March 31, 2000, financial statements through
the period ending on the Waiver Termination Date, agree to extend the Bridge
Loan Period to the Waiver Termination Date, and agree to amend the due date for
the payment of principal, interest, and unused commitment fees otherwise due on
or before July 31, 2000, with respect to the Revolving Credit and the Term Loans
(including such payments described in Sections 2.1 and 2.2 of the Seventh
Amendment) to the Waiver Termination Date, provided that:

                   (a)     until the Obligations are paid in full, the Borrower
         shall provide to the Banks a weekly Budget pursuant to Section 1.14(f)
         of the Credit Agreement and such Budget shall be subject to the
         Approved Budget and reconciliation procedures set forth therein,
         regardless of whether or not then being accompanied by a request for a
         Borrowing of Bridge Loans;

                   (b)     at all times on and after the date hereof (i) all
         proceeds from the sale of any assets of the Borrower and its
         Subsidiaries (including, without limitation, proceeds from the sale of
         the PPM Businesses or any part thereof), and (ii) cash receipts arising
         from the operation of the business of the Borrower and its Subsidiaries
         not applied pursuant to an Approved Budget, shall in each case be
         remitted promptly upon receipt to the Agent; and

                   (c)     except to the extent applied to payments pursuant to
         an Approved Budget or applied to the Obligations owing to the Banks,
         proceeds received pursuant to clause (c) above shall be held by the
         Agent as collateral for the remaining Obligations owing to the Banks
         (the Agent hereby being granted a Lien on and right of set-off for the
         benefit of the Banks against all such amounts so held).

The Borrower hereby acknowledges and agrees to the foregoing conditions. The
Borrower also hereby acknowledges and agrees that (i) any restructuring of the
terms and conditions relating to the Obligations shall be subject to the Banks'
consent, which may be given or withheld in their


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Vision Twenty-One, Inc.
July 21, 2000
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discretion and (ii) any sale of the Borrower's or its Subsidiaries' assets or
businesses shall be subject to the prior written consent of the Banks, and all
proceeds from any such sale represent proceeds of the Banks' Collateral, to be
held by the Agent or applied to the Obligations pursuant to the terms of the
Credit Agreement as modified hereby.

         Except as specifically modified hereby, all of the terms and conditions
of the Credit Agreement and the other Loan Documents shall stand and remain
unchanged and in full force and effect. This waiver shall become effective upon
the execution and delivery hereof by each of the Banks and the Borrower as set
forth below. This waiver may be executed in counterparts and by different
parties on separate counterpart signature pages, each of which shall be an
original and all of which taken together shall constitute one and the same
instrument. This waiver shall be governed by, and construed in accordance with,
the laws of the State of Illinois.

                           [SIGNATURE PAGES TO FOLLOW]


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Vision Twenty-One, Inc.
July 21, 2000
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         This waiver letter is entered into by and among the parties hereto as
of the date first above written.

<TABLE>
<S>                                                   <C>
BANK OF MONTREAL, in its individual                   BANK ONE TEXAS, N.A.
capacity as a Bank and as Agent

                                                      By: /s/Ronnie Kaplan
By: /s/ Jack J. Kane                                      Name: Ronnie Kaplan
    Name: Jack J. Kane                                    Title: Vice President
    Title: Director

PACIFICA PARTNERS I, L.P.                             PILGRIM PRIME RATE TRUST

By:      Imperial Credit Asset Management, as         By:      Pilgrim Investments, Inc., as its
         its Investment Manager                                Investment Manager


By: /s/ Dean K. Kawai                                 By: /s/ Charles E. LeMieux
    Name: Dean K. Kawai                                   Name: Charles E. LeMieux, CFA
    Title: Vice President                                 Title: Vice President

PILGRIM AMERICA HIGH INCOME                           MERRILL LYNCH BUSINESS FINANCIAL
INVESTMENTS LTD.                                      SERVICES, INC.

By:      Pilgrim Investments, Inc., as its
         Investment Manager                           By: /s/ Gary L. Stewart
                                                          Name: Gary L. Stewart
                                                          Title: Vice President
By: /s/ Charles E. LeMieux
    Name: Charles E. LeMieux, CFA
    Title: Vice President
</TABLE>

         Acknowledged and agreed to as of the date first above written.

                                              VISION TWENTY-ONE, INC.


                                              By: /s/ Bruce Maller
                                                  Name: Bruce Maller
                                                  Title: Chairman