<PAGE>   1

                                                                   EXHIBIT 4.15

                             VISION TWENTY-ONE, INC.
                       FIRST AMENDMENT TO CREDIT AGREEMENT

         This First Amendment to Credit Agreement (herein, the "Amendment") is
entered into as of February 23, 1999, among Vision Twenty-One, Inc., a Florida
corporation, the Banks party hereto, and Bank of Montreal as Agent for the
Banks.


                             PRELIMINARY STATEMENTS

          A.    The Borrower, the Banks, and the Agent entered into an Amended
and Restated Credit Agreement, dated as of July 1, 1998 (herein, the "Credit
Agreement"). All capitalized terms used herein without definition shall have the
same meanings herein as such terms have in the Credit Agreement.

          B.    The Credit Agreement currently provides for, among other things,
a $22,500,000 five-year amortizing acquisition term loan facility and a
$70,000,000 seven-year amortizing term loan.

          C.    The Borrower and the Banks have agreed to reduce the Term A
Credit Commitments from $22,500,000 to $12,500,000 and modify the $70,000,000
term credit facility described above into a $20,000,000 five-year amortizing
term loan and a $50,000,000 seven-year amortizing term loan, and to make certain
other changes to the Credit Agreement as more fully provided for in this
Amendment.

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

SECTION 1.          AMENDMENTS.

         Subject to the satisfaction of the conditions precedent set forth in
Section 3 below, the Credit Agreement shall be and hereby is amended as follows:

                  1.1      The first sentence of Section 1.1 of the Credit
         Agreement shall be amended and restated to read as follows:

                  Subject to the terms and conditions hereof, each Bank, by its
                  acceptance hereof, severally agrees to make a loan or loans
                  (individually a "Revolving Loan" and collectively the
                  "Revolving Loans") to the Borrower from time to time on a
                  revolving basis up to the amount of such Bank's Revolving
                  Credit Commitment, subject to any reductions thereof pursuant
                  to the terms hereof, before the Revolving Credit Termination
                  Date.

<PAGE>   2

                  1.2.     Section 1.3 of the Credit Agreement shall be amended
         and restated in its entirety to read as follows:

                           Section 1.3.   Term Credit Commitments. (a) Subject
                  to the terms and conditions hereof, each Bank, by its
                  acceptance hereof, severally agrees to make one or more loans
                  (individually a "Term A Loan" and collectively the "Term A
                  Loans") to the Borrower from time to time in the aggregate
                  amount of such Bank's Term A Credit Commitment, subject to any
                  reduction thereof pursuant to the terms hereof, on or before
                  the Term A Credit Commitment Termination Date (at which time
                  the Term A Credit Commitments of the Banks shall expire). Each
                  Borrowing of Term A Loans shall be made ratably by the Banks
                  in proportion to their respective Term A Loan Percentages.
                  Each Borrowing of Term A Loans shall be used solely for the
                  purposes provided in Section 6.4 hereof. Each Borrowing of
                  Term A Loans shall be in an amount of $1,000,000 or such
                  greater amount which is an integral multiple of $100,000. As
                  provided in Section 1.6(a) hereof, the Borrower may elect that
                  each Borrowing of Term A Loans be either Base Rate Loans or
                  Eurodollar Loans. The principal amount of each Term A Loan
                  made by a Bank to the Borrower shall permanently reduce the
                  amount available to the Borrower under such Bank's Term A
                  Credit Commitment, and no amount repaid or prepaid on any Term
                  A Loan may be borrowed again.

                           (b)      On or about July 1, 1998, term loans in the
                  aggregate principal amount of $70,000,000 were made available
                  to the Borrower by the Banks (herein, the "Term B/C Credit
                  Commitments") and, of the outstanding principal balance
                  thereof, $20,000,000 are currently outstanding and owing to
                  certain of the Banks in the amounts set forth on Schedule 1
                  attached hereto (individually a "Term B Loan" and collectively
                  the "Term B Loans"). Each Borrowing of Term B Loans shall be
                  made and maintained ratably by the Banks in proportion to
                  their respective Term B Loan Percentages. As provided in
                  Section 1.6(a) hereof, the Borrower may elect that each
                  Borrowing of Term B Loans be either Base Rate Loans or
                  Eurodollar Loans. No amount repaid or prepaid on any Term B
                  Loan may be borrowed again.

                           (c)      On or about July 1, 1998, term loans in the
                  aggregate principal amount of $70,000,000 were made available
                  to the Borrower by the Banks under the Term B/C Credit
                  Commitments and, of the outstanding principal balance thereof,
                  $50,000,000 are currently outstanding and owing to certain of
                  the Banks in the amounts set forth in Schedule 1 attached
                  hereto



                                      -2-
<PAGE>   3

                  (individually a "Term C Loan" and collectively the "Term C
                  Loans"). Each Borrowing of Term C Loans shall be made and
                  maintained ratably by the Banks in proportion to their
                  respective Term C Loan Percentages. As provided in Section
                  1.6(a) hereof, the Borrower may elect that each Borrowing of
                  Term C Loans be either Base Rate Loans, Eurodollar Loans, or
                  Fixed Rate Loans. No amount repaid or prepaid on any Term C
                  Loan may be borrowed again.

                  1.3.     Subsections (c) and (d) of Section 1.4 of the Credit
         Agreement shall be amended and restated to read as follows:

                           (c)      Fixed Rate Loans. Each Fixed Rate Loan made
                  or maintained by a Bank shall bear interest (computed on the
                  basis of a year of 360 days and the actual days elapsed) on
                  the unpaid principal amount thereof from the date such Loan is
                  advanced or created by conversion from a Base Rate Loan or
                  Eurodollar Loan until maturity (whether by acceleration or
                  otherwise) at a rate per annum equal to the sum of the
                  Applicable Margin with respect to Eurodollar Loans as from
                  time to time in effect plus the Adjusted Fixed Rate applicable
                  to the relevant Borrowing of Term C Loans, payable on the last
                  day of each March, June, September, and December occurring
                  after the relevant Borrowing of Fixed Rate Loans is advanced
                  or created and at maturity (whether by acceleration or
                  otherwise). Fixed Rate Loans shall only be available for
                  Borrowings of Term C Loans. In the event the Borrower elects
                  that a Borrowing of Term C Loans constitute Fixed Rate Loans,
                  such election shall be irrevocable and remain in effect with
                  respect to such Borrowing of Term C Loans from the date such
                  Fixed Rate Loans are advanced or created by conversion from a
                  Base Rate Loan or Eurodollar Loan through the final maturity
                  date of the Term C Loans. It being acknowledged by the parties
                  hereto that $35,000,000 of Fixed Rate Loans were advanced to
                  the Borrower on or about July 1, 1998, which Fixed Rate Loans
                  are outstanding as Term C Loans hereunder.

                           "Adjusted Fixed Rate" means, for any Borrowing of
                  Fixed Rate Loans, a rate per annum determined in accordance
                  with the following formula:

<TABLE>
                            <S>                           <C>      <C>
                            Adjusted Fixed Rate           =        Fixed Rate + (Adjusted
                                                                   LIBOR-LIBOR, as
                                                                   determined by the
                                                                   Floating Rate Payor
                                                                   pursuant to clause (d)
                                                                   below)
</TABLE>



                                      -3-
<PAGE>   4

                           "Fixed Rate" means, with respect to a Borrowing of
                  Fixed Rate Loans advanced or created by conversion from a Base
                  Rate Loan or Eurodollar Loan on the same day, the rate per
                  annum quoted to the Borrower by the Floating Rate Payor on the
                  date on which such Borrowing is to be advanced or created, it
                  being acknowledged and agreed that the Fixed Rate shall be
                  established at the time of each Borrowing of Term C Loans by
                  the Floating Rate Payor in its sole discretion.

                           "Floating Rate Payor" means Bank of Montreal, in its
                  capacity as a payment obligor under Section 1.4(d) below.

                           (d)      Floating Rate Payor Obligation. Subject to
                  receipt by the Agent of payment in full of interest due by the
                  Borrower with respect to each Borrowing of Fixed Rate Loans,
                  the Agent will remit to the Floating Rate Payor the interest
                  so paid by the Borrower and the Floating Rate Payor shall pay
                  to the Agent for distribution to the Banks ratably an amount
                  equal to interest which would have accrued on such Borrowing
                  during the prior 3-month period at a rate per annum equal to
                  the sum of the Applicable Margin with respect to Eurodollar
                  Loans in effect during such period plus the Adjusted LIBOR
                  (computed on the basis of a year of 360 days and the actual
                  number of days elapsed) (as determined by the Floating Rate
                  Payor on the first day of the relevant calendar quarter and
                  determined as if the relevant Interest Period was 3 months,
                  provided during the first three months following the date
                  hereof such rate shall be determined on the first day of each
                  month and determined as if the relevant Interest Period was 1
                  month). In the event any such Fixed Rate Loans bear interest
                  at the default rate provided for in Section 1.10(c) hereof,
                  the Banks shall also be entitled to receive from the Floating
                  Rate Payor their pro rata share of any additional interest
                  provided for therein, based on their Percentages of the
                  relevant Borrowing of Term C Loans, to the extent paid by the
                  Borrower. In the event interest on any such Fixed Rate Loan is
                  not paid in full by the Borrower, then the Floating Rate Payor
                  shall be obligated to pay to the Agent for distribution to the
                  Banks an amount determined by multiplying the amounts due the
                  Banks as set forth above times a fraction, the numerator of
                  which is the amount of interest actually paid by the Borrower
                  to the Agent and the denominator of which is the amount of
                  interest due from Borrower with respect to such Fixed Rate
                  Loans.

                  1.4.     Section 1.6 of the Credit Agreement shall be amended
         by deleting all references therein to "Term B Loans" and inserting
         reference to "Term C Loans" in lieu thereof.



                                      -4-
<PAGE>   5

                  1.5.     Section 1.7 of the Credit Agreement shall be amended
         and restated in its entirety to read as follows:

                           Section 1.7. Interest Periods.    As provided in
                  Section 1.6(a) hereof, at the time of each request to advance,
                  continue, or create by conversion a Borrowing of Eurodollar
                  Loans, the Borrower shall select an Interest Period applicable
                  to such Loans from among the available options. The term
                  "Interest Period" means the period commencing on the date a
                  Borrowing of Loans is advanced, continued, or created by
                  conversion and ending: (a) in the case of Base Rate Loans, on
                  the last day of the calendar quarter in which such Borrowing
                  is advanced, continued, or created by conversion (or on the
                  last day of the following calendar quarter if such Loan is
                  advanced, continued or created by conversion on the last day
                  of a calendar quarter) and (b) in the case of a Eurodollar
                  Loan, 1, 2, 3, or 6 months thereafter; provided, however,
                  that:

                           (a)      any Interest Period for a Borrowing of
                  Revolving Loans consisting of Base Rate Loans that otherwise
                  would end after the Revolving Credit Termination Date shall
                  end on the Revolving Credit Termination Date, and any Interest
                  Period for a Borrowing of Term Loans consisting of Base Rate
                  Loans that otherwise would end after the final maturity date
                  of the relevant Term Loans shall end on the final maturity
                  date of such Term Loans;

                           (b)      no Interest Period with respect to any
                  portion of the Term A Loans shall extend beyond the final
                  maturity date of the Term A Loans, no Interest Period with
                  respect to any portion of the Term B Loans shall extend beyond
                  the final maturity date of the Term B Loans, no Interest
                  Period with respect to any portion of the Term C Loans shall
                  extend beyond the final maturity date of the Term C Loans, and
                  no Interest Period with respect to any portion of the
                  Revolving Loans shall extend beyond the Revolving Credit
                  Termination Date;

                           (c)      no Interest Period with respect to any
                  portion of the Term A Loans consisting of Eurodollar Loans
                  shall extend beyond a date on which the Borrower is required
                  to make a scheduled payment of principal on the Term A Loans,
                  unless the sum of (i) the aggregate principal amount of Term A
                  Loans that are Base Rate Loans plus (ii) the aggregate
                  principal amount of Term A Loans that are Eurodollar Loans
                  with Interest Periods expiring on or before such date equals
                  or exceeds the principal amount to be paid on the Term A Loans
                  on such payment date;



                                      -5-
<PAGE>   6

                           (d)      no Interest Period with respect to any
                  portion of the Term B Loans consisting of Eurodollar Loans
                  shall extend beyond a date on which the Borrower is required
                  to make a scheduled payment of principal on the Term B Loans,
                  unless the sum of (i) the aggregate principal amount of Term B
                  Loans that are Base Rate Loans plus (ii) the aggregate
                  principal amount of Term B Loans that are Eurodollar Loans
                  with Interest Periods expiring on or before such date equals
                  or exceeds the principal amount to be paid on the Term B Loans
                  on such payment date;

                           (e)      no Interest Period with respect to any
                  portion of the Term C Loans consisting of Eurodollar Loans
                  shall extend beyond a date on which the Borrower is required
                  to make a scheduled payment of principal on the Term C Loans,
                  unless the sum of (i) the aggregate principal amount of Term C
                  Loans that are Base Rate Loans plus (ii) the aggregate
                  principal amount of Term C Loans that are Eurodollar Loans
                  with Interest Periods expiring on or before such date plus
                  (iii) the aggregate principal amount of Term C Loans that are
                  Fixed Rate Loans scheduled to mature on or before such date
                  equals or exceeds the principal amount to be paid on the Term
                  C Loans on such payment date;

                           (f)      whenever the last day of any Interest Period
                  would otherwise be a day that is not a Business Day, the last
                  day of such Interest Period shall be extended to the next
                  succeeding Business Day, provided that, if such extension
                  would cause the last day of an Interest Period for a Borrowing
                  of Eurodollar Loans to occur in the following calendar month,
                  the last day of such Interest Period shall be the immediately
                  preceding Business Day; and

                           (g)      for purposes of determining an Interest
                  Period for a Borrowing of Eurodollar Loans, a month means a
                  period starting on one day in a calendar month and ending on
                  the numerically corresponding day in the next calendar month;
                  provided, however, that if there is no numerically
                  corresponding day in the month in which such an Interest
                  Period is to end or if such an Interest Period begins on the
                  last Business Day of a calendar month, then such Interest
                  Period shall end on the last Business Day of the calendar
                  month in which such Interest Period is to end.

                  1.6.     Subsection (c) of Section 1.8 of the Credit Agreement
         shall be amended and restated and a new subsection(d) shall be added to
         Section 1.8 of Credit Agreement, each of which shall read as follows:

                           (c)      Scheduled Payments of Term B Loans. The
                  Borrower shall make principal payments on the Term B Loans in



                                      -6-
<PAGE>   7

                  installments on the last day of each March, June, September
                  and December in each year, commencing with the calendar
                  quarter ending September 30, 2000, with the amount of each
                  such installment to equal to the amount set forth in Column B
                  below opposite the relevant due date as set forth in Column A
                  below:

<TABLE>
<CAPTION>
                                                         COLUMN B
                               COLUMN A         SCHEDULED PRINCIPAL PAYMENT
                             PAYMENT DATE          ON THE TERM B LOANS

                             <S>                <C>
                               09/30/00               $1,250,000.00
                               12/31/00               $1,250,000.00
                               03/31/01               $1,250,000.00
                               06/30/01               $1,250,000.00
                               09/30/01               $1,250,000.00
                               12/31/01               $1,250,000.00
                               03/31/02               $1,250,000.00
                               06/30/02               $1,250,000.00
                               09/30/02               $1,250,000.00
                               12/31/02               $1,250,000.00
                               03/31/03               $3,750,000.00
                               06/30/03               $3,750,000.00
</TABLE>

                  , it being agreed that the final payment of both principal and
                  interest not sooner paid on the Term B Loans shall be due and
                  payable on the Term B Credit Final Maturity Date. Each such
                  principal payment shall be applied to the Banks holding the
                  Term B Notes pro rata based on their Term B Loan Percentages.

                           (d)      Scheduled Payments of Term C Loans. The
                  Borrower shall make principal payments on the Term C Loans in
                  installments on the last day of each June in each year,
                  commencing June 30, 1999, with the amount of each such
                  installment to equal 1.0% of the original aggregate principal
                  amount of the Term C Loans made to the Borrower (with each
                  such installment deemed to reduce each Fixed Rate Loan then
                  outstanding by an amount equal to 1.0% of the original
                  principal amount thereof), except that the final payment of
                  both principal and interest not sooner paid on the Term C
                  Loans shall be due and payable on the Term C Credit Final
                  Maturity Date. Each such principal payment shall be applied to
                  the Banks holding the Term C Notes pro rata based upon their
                  Term C Loan Percentages.



                                      -7-
<PAGE>   8

                  1.7.     The last sentence of Section 1.9(a) of the Credit
         Agreement shall be amended and restated to read as follows:

                  No amount of any Term Loans paid or prepaid may be reborrowed.

                  1.8.     Clauses (ii) and (iii) of Section 1.9(b) of the
         Credit Agreement shall be amended and restated and a new clause (iv)
         shall be added to Section 1.9(b) of the Credit Agreement, each of which
         shall read as follows:

                           (ii)     If after the date of this Agreement the
                  Borrower or any Subsidiary shall issue any Indebtedness for
                  Borrowed Money, other than Indebtedness for Borrowed Money
                  permitted by Section 8.13 hereof, the Borrower shall promptly
                  notify the Agent of the net cash proceeds (i.e., gross
                  proceeds of cash or cash equivalents minus the costs directly
                  incurred and payable as a result thereof) of such issuance to
                  be received by or for the account of the Borrower or such
                  Subsidiary in respect thereof. Promptly upon, and in no event
                  later than the Business Day after, receipt by the Borrower or
                  such Subsidiary of net cash proceeds of such issuance, the
                  Borrower shall prepay the Term Loans in an aggregate amount
                  equal to 100% of the amount of such net cash proceeds. The
                  amount of such prepayment shall be applied on a ratable basis
                  among the then outstanding Term A Loans, Term B Loans and Term
                  C Loans, and on a ratable basis among all remaining payments
                  on such Term A Loans, Term B Loans and Term C Loans. The
                  Borrower acknowledges that its performance hereunder shall not
                  limit the rights and remedies of the Banks arising from any
                  breach of Section 8.13 hereof.

                           (iii)    Notwithstanding anything to the contrary
                  contained in this Section 1.9(b) or elsewhere in this
                  Agreement, any Bank with an outstanding Term C Loan shall have
                  the option to waive any mandatory prepayment of such Term C
                  Loan pursuant to clause (ii) of this Section 1.9(b) (each such
                  prepayment a "Waiveable Mandatory Term C Loan Prepayment")
                  upon the terms and provisions set forth in this Section
                  1.9(b)(iii). In the event any such Bank desires to waive such
                  Bank's right to receive any such Waiveable Mandatory Term C
                  Loan Prepayment in whole or in part, such Bank shall so advise
                  the Agent no later than the date on which such prepayment is
                  to occur, which notice shall also includes the amount such
                  Bank desires to receive in respect of such prepayment. If any
                  such Bank does not provide such notice, it will be deemed to
                  have accepted 100% of the total amount. In the event that any
                  such Bank waives all or any part of such right to receive any
                  such Waiveable Mandatory Term C Loan Prepayment, the Agent
                  shall apply 100% of the amount so waived by such Bank



                                      -8-
<PAGE>   9

                  to the Term A Loans and Term B Loans then outstanding in
                  accordance with the relevant clause of this Section 1.9(b),
                  provided that no such waiver request shall be honored
                  following the prepayment in full of the Term A Loans and Term
                  B Loans.

                           (iv)     Unless the Borrower otherwise directs,
                  prepayments of Loans under this Section 1.9(b) shall be
                  applied first to Borrowings of Base Rate Loans until payment
                  in full thereof with any balance applied to Borrowings of
                  Eurodollar Loans in the order in which their Interest Periods
                  expire and thereafter, in the case of the Term C Loans, with
                  any balance applied to the Fixed Rate Loans. Each prepayment
                  of Loans under this Section 1.9(b) shall be made by the
                  payment of the principal amount to be prepaid and accrued
                  interest thereon to the date of prepayment together with any
                  amounts due the Banks under Section 1.12 hereof. Each
                  prefunding of L/C Obligations shall be made in accordance with
                  Section 9.4 hereof.

                  1.9.     Subsection (c) of Section 1.11 of the Credit
         Agreement shall be amended and restated in its entirety to read as
         follows:

                           (c)      (i) The Term B Loans made to the Borrower by
                  a Bank shall be evidenced by a single promissory note of the
                  Borrower issued to such Bank in the form of Exhibit F-1
                  hereto. Each such promissory note is hereinafter referred to
                  as a "Term B Note" and collectively such promissory notes are
                  referred to as the "Term B Notes."

                                    (ii) The Term C Loans made to the Borrower
                  by a Bank shall be evidenced by a single promissory note of
                  the Borrower issued to such Bank in the form of Exhibit F-2
                  hereto. Each such promissory note is hereinafter referred to
                  as a "Term C Note" and collectively such promissory notes are
                  referred to as the "Term C Notes."

                 1.10.     Subsection (c) of Section 1.13 of the Credit
         Agreement shall be amended and restated to read as follows:

                           (c)      Intentionally deleted.

                 1.11.     Subsection (c) of Section 2.1 of the Credit Agreement
         shall be amended and restated to read as follows:

                           (c)      Intentionally deleted.



                                      -9-
<PAGE>   10


                 1.12.     The definition of "Applicable Margin" appearing in
         Section 5.1 of the Credit Agreement shall be amended and restated in
         its entirety to read as follows (and the Applicable Margin, as so
         amended, shall be effective retroactive to January 1, 1999):

                           "Applicable Margin" means, with respect to Loans,
                  Reimbursement Obligations, and the commitment fees and letter
                  of credit fees payable under Section 2.1 hereof, the rate per
                  annum specified below:

<TABLE>
                         <S>                                                                   <C>
                         Applicable Margin for Base Rate Loans under Revolving Credit,
                         Term A Loans and Term B Loans, and Reimbursement Obligations:          1.5%

                         Applicable Margin for Eurodollar Loans under Revolving Credit,
                         Term A Loans and Term B Loans, and letter of credit fee:               3.0%

                         Applicable Margin for Revolving Credit Commitment fee and
                         Term A Credit Commitment fee:                                         .625%

                         Applicable Margin for Base Rate Loans under Term C Loans               1.5%

                         Applicable Margin for Eurodollar Loans under Term C Loans            3.625%
</TABLE>

                  ; provided, however, that the Applicable Margin shall be
                  subject to quarterly adjustments on the first Pricing Date,
                  and thereafter from one Pricing Date to the next the
                  Applicable Margin shall mean a rate per annum determined in
                  accordance with the following schedule:



                                      -10-
<PAGE>   11

<TABLE>
<CAPTION>
                          APPLICABLE          APPLICABLE
                          MARGIN FOR          MARGIN FOR
                           BASE RATE          EURODOLLAR
                          LOANS UNDER        LOANS UNDER           APPLICABLE
                           REVOLVING          REVOLVING          MARGIN FOR THE
                        CREDIT, TERM A       CREDIT, TERM          REVOLVING
                           CREDIT AND          A CREDIT              CREDIT             APPLICABLE        APPLICABLE
     TOTAL FUNDED        TERM B CREDIT,       AND TERM B           COMMITMENT           MARGIN FOR        MARGIN FOR
    DEBT/ADJUSTED             AND            CREDIT, AND         FEE AND TERM A          BASE RATE        EURODOLLAR
     EBITDA RATIO        REIMBURSEMENT        LETTER OF              CREDIT             LOANS UNDER       LOANS UNDER
       FOR SUCH           OBLIGATIONS         CREDIT FEE           COMMITMENT             TERM C:           TERM C
     PRICING DATE          SHALL BE:           SHALL BE:          FEE SHALL BE:           CREDIT:           CREDIT:

  <S>                   <C>                  <C>                 <C>                    <C>               <C>
  Greater than 3.0 to         1.5%                3.0%                .625%                 1.5%             3.625%
  1.0

  Equal to or less          1.375%              2.875%                .625%               1.375%             3.625%
  than 3.0 to 1.0,
  but greater than
  2.5 to 1.0

  Equal to or less           1.25%               2.75%                 .50%                1.25%             3.375%
  than 2.5 to 1.0,
  but greater than
  2.0 to 1.0

  Equal to or less            1.0%                2.5%                 .50%                 1.0%             3.375%
  than 2.0 to 1.0,
  but greater than
  1.5 to 1.0

  Equal to or less            .75%               2.25%                 .50%                 .75%             3.375%
  than 1.5 to 1.0
</TABLE>


                  For purposes hereof, the term "Pricing Date" means, for any
                  fiscal quarter of the Borrower ending on or after December 31,
                  1998, the date on which the Agent is in receipt of the
                  Borrower's most recent financial statements for the fiscal
                  quarter then ended, pursuant to Section 8.5(b) or (c) hereof.
                  The Applicable Margin shall be established based on the Total
                  Funded Debt/Adjusted EBITDA Ratio for the most recently
                  completed fiscal quarter and the Applicable Margin established
                  on a Pricing Date shall remain in effect until the next
                  Pricing Date. If the Borrower has not delivered its financial
                  statements by the date such financial statements (and, in the
                  case of the year-end financial statements, audit report) are
                  required to be delivered under Section 8.5(b) or



                                      -11-
<PAGE>   12

                  (c) hereof, until such financial statements and audit report
                  are delivered, the Applicable Margin shall be the highest
                  Applicable Margin (i.e., the Total Funded Debt/Adjusted EBITDA
                  Ratio shall be deemed to be greater than 3.0 to 1.0). If the
                  Borrower subsequently delivers such financial statements
                  before the next Pricing Date, the Applicable Margin
                  established by such late delivered financial statements shall
                  take effect from the date of delivery until the next Pricing
                  Date. In all other circumstances, the Applicable Margin
                  established by such financial statements shall be in effect
                  from the Pricing Date that occurs immediately after the end of
                  the Borrower's fiscal quarter covered by such financial
                  statements until the next Pricing Date. Each determination of
                  the Applicable Margin made by the Agent in accordance with the
                  foregoing shall be conclusive and binding on the Borrower and
                  the Banks if reasonably determined.

                 1.13.     The definitions of "Commitments", "Credit", "EBITDA",
         "Loan", "Majority Banks", "Notes", "Percentage", "Required Banks",
         "Revolving Credit Commitment", "Term A Credit Commitment", "Term B
         Credit Commitment", "Term B Final Maturity Date", "Term B Loan", "Term
         B Loan Percentage", "Term B Note", "Term Credits" and "Term Loans"
         appearing in Section 5.1 of the Credit Agreement shall be amended and
         restated in their entirety to read as follows:

                  "Commitments" means the Revolving Credit Commitments, the L/C
                  Commitment, the Term A Credit Commitments and the Term B/C
                  Credit Commitments.

                  "Credit" means any one of the Revolving Credit, the Term A
                  Credit, the Term B Credit or the Term C Credit.

                  "EBITDA" means, with reference to any period, Net Income for
                  such period plus the sum (without duplication) of all amounts
                  deducted in arriving at such Net Income amount in respect of
                  (a) Interest Expense for such period, (b) federal, state and
                  local income taxes for such period, (c) depreciation of fixed
                  assets and amortization of intangible assets for such period,
                  (d) one-time charges incurred on or about January 30, 1998,
                  arising out of the prepayment of the indebtedness owing to
                  Prudential Securities Credit Corporation on or about January
                  30, 1998, (e) one-time charges incurred on or about July 1,
                  1998, arising out of the refinancing and restructuring of the
                  indebtedness owing to Bank of Montreal and the other lenders
                  party to the Original Credit Agreement, and (f) non-recurring
                  expenses in an aggregate amount up to $9,000,000 incurred as a
                  result of the implementation of the Ernst & Young
                  restructuring plan.



                                      -12-
<PAGE>   13

                  "Loan" means a Base Rate Loan or Eurodollar Loan or Fixed
                  Rate Loan, each of which is a "type" of Loan hereunder,
                  outstanding as a Revolving Loan, a Term A Loan, a Term B Loan
                  or a Term C Loan, as applicable.

                  "Majority Banks" means, as of the date of determination
                  thereof, Banks whose outstanding Loans and interests in
                  Letters of Credit and Unused Revolving Credit Commitments and
                  unfunded Term A Credit Commitments constitute more than 50% of
                  the sum of the total outstanding Loans, interests in Letters
                  of Credit, Unused Revolving Credit Commitments and unfunded
                  Term A Credit Commitments of the Banks.

                  "Notes" means and includes the Revolving Notes, the Term A
                  Notes, the Term B Notes and the Term C Notes.

                  "Percentage" means for any Bank its Revolver Percentage, Term
                  A Loan Percentage, Term B Loan Percentage or Term C Loan
                  Percentage, as applicable.

                  "Required Banks" means, as of the date of determination
                  thereof, Banks whose outstanding Loans and interests in
                  Letters of Credit and Unused Revolving Credit Commitments and
                  unfunded Term A Credit Commitments constitute more than
                  66 2/3% of the sum of the total outstanding Loans, interests
                  in Letters of Credit, Unused Revolving Credit Commitments and
                  unfunded Term A Credit Commitments of the Banks.

                  "Revolving Credit Commitment" means, as to any Bank, the
                  obligation of such Bank to make Revolving Loans and to
                  participate in Letters of Credit issued for the account of the
                  Borrower hereunder in an aggregate principal or face amount at
                  any one time outstanding not to exceed the amount set forth
                  opposite such Bank's name or Schedule 1 attached hereto and
                  made a part hereof, as the same may be reduced or modified at
                  any time and from time to time pursuant to the terms hereof.
                  The Borrower and the Banks acknowledge and agree that the
                  Revolving Credit Commitments of the Banks aggregate $7,500,000
                  on the date of this Agreement.

                  "Term A Credit Commitment" means, as to any Bank, the
                  obligation of such Bank to make Term A Loans to the Borrower
                  hereunder in an aggregate principal amount at any one time
                  outstanding not to exceed the amount set forth opposite such
                  Bank's name on Schedule 1 attached hereto and made a part
                  hereof, as the same may be reduced or modified at any time and



                                      -13-
<PAGE>   14

                  from time to time pursuant to the terms hereof. The Borrower
                  and the Banks acknowledge and agree that the Term A Credit
                  Commitments of the Banks aggregate $12,500,000 on the date of
                  this Agreement.

                  "Term B/C Credit Commitments" means the obligations of the
                  Banks to make Term B Loans and Term C Loans to the Borrower on
                  or about July 1, 1998 in the aggregate amount of $70,000,000,
                  which obligations have been satisfied and pursuant to which no
                  additional advances may be availed of by the Borrower
                  thereunder.

                  "Term B Credit Final Maturity Date" means June 30, 2003.

                  "Term B Loan" is defined in Section 1.3(b) hereof and, as so
                  defined, includes a Base Rate Loan or a Eurodollar Loan, each
                  of which is a "type" of Term B Loan hereunder.

                  "Term B Loan Percentage" means, for each Bank, the percentage
                  held by such Bank of the aggregate principal amount of all
                  Term B Loans then outstanding.

                  "Term B Note" is defined in Section 1.11(c)(i) hereof.

                  "Term Credits" means and includes the Term A Credit, the Term
                  B Credit and the Term C Credit.

                  "Term Loans" means and includes the Term A Loans, the Term B
                  Loans and the Term C Loans.

                 1.14.     Section 5.1 of the Credit Agreement shall be further
amended by adding the following definitions:

                  "Term C Credit" means the credit facility for Term C Loans
                  described in Section 1.3(c) hereof.

                  "Term C Credit Final Maturity Date" means June 30, 2005.

                  "Term C Loan" is defined in Section 1.3(c) hereof and, as so
                  defined, includes a Base Rate Loan or a Eurodollar Loan or a
                  Fixed Rate Loan, each of which is a "type" of Term C Loan
                  hereunder.

                  "Term C Loan Percentage" means, for each Bank, the percentage
                  held by such Bank of the aggregate principal amount of all
                  Term C Loans then outstanding.

                  "Term C Note" is defined in Section 1.11(c)(ii) hereof.



                                      -14-
<PAGE>   15

                 1.15.     Section 5.1 of the Credit Agreement shall be amended
         by deleting the "Term B Credit Commitment Termination Date" in its
         entirety.

                 1.16.     The first sentence of Section 6.4 of the Credit
         Agreement shall be amended and restated to read as follows:

                  The Borrower shall use the proceeds of (i) the Term A Loans
                  solely for the purpose of financing one or more acquisitions
                  permitted by Section 8.13(k) of this Agreement and/or Capital
                  Expenditures permitted under this Agreement and (ii) the Term
                  B Loans and the Term C Loans made on the date of this
                  Agreement, and the Revolving Loans and the Letters of Credit
                  from time to time made available hereunder to refinance
                  existing indebtedness on the date of this Agreement and for
                  its general working capital purposes and such other legal and
                  proper purposes as are consistent with all applicable laws.

                 1.17.     Sections 8.29 and 8.30 of the Credit Agreement shall
         be amended and restated in their entirety to read as follows:

                           Section 8.29.  Interest Rate Protection. Any interest
                  rate swaps, interest rate caps, interest rate collars or other
                  recognized interest rate hedging arrangements (collectively,
                  "Hedging Arrangements") entered into after the date of this
                  Agreement by the Borrower shall be on terms and conditions,
                  and with such parties, reasonably acceptable to the Agent. If
                  the Borrower enters into any Hedging Arrangements with any
                  Bank, the Borrower's obligations to such Bank in connection
                  with such Hedging Arrangements do not constitute usage of the
                  Commitments of such Bank.

                           Section 8.30.  Year 2000 Compliance. The Borrower
                  shall take all reasonable actions necessary and commit
                  adequate resources to assure that its computer-based and other
                  systems (and those of all Subsidiaries) are able to
                  effectively process data, including dates before, on and after
                  January 1, 2000, without experiencing any Year 2000 Problems
                  that could cause a Material Adverse Effect. At the request of
                  the Agent or the Required Banks, the Borrower will provide the
                  Banks with assurances and substantiations (including, but not
                  limited to, the results of internal or external reports
                  prepared in the ordinary course of business or at the request
                  of the Agent or the Required Banks) reasonably acceptable to
                  the Agent and the Required Banks as to the capability of the
                  Borrower and its Subsidiaries to conduct its and their
                  businesses and operations before, on, and after January 1,
                  2000, without experiencing a Year 2000 Problem that,
                  individually or in



                                      -15-
<PAGE>   16

                  the aggregate, is reasonably likely to have a Material Adverse
                  Effect.

                 1.18.     Section 12.1(b) of the Credit Agreement shall be
         amended by adding at the end thereof the following additional sentence:

                  If a Bank is unable to deliver a Form 1001 or Form 4224 but
                  claims exemption from United States withholding tax under
                  Section 871(h) or 881(c) of the Code with respect to payments
                  of "portfolio interest", such Bank shall provide to the
                  Borrower and the Agent within the time period set forth above
                  a Form W-8 or any successor form prescribed by the Internal
                  Revenue Service, together with a certificate representing that
                  such Bank is not a bank for purposes of Section 881(c) of the
                  Code, is not a 10-percent shareholder (within the meaning of
                  Section 871(h)(3)(B) of the Code) of the Borrower and is not a
                  controlled foreign corporation related to the Borrower (within
                  the meaning of Section 864(d)(4) of the Code) and such other
                  forms or certificates as the Borrower or the Agent may
                  reasonably request establishing such Bank's exemption from
                  United States withholding tax.

                 1.19.     Section 12.12 of the Credit Agreement shall be
         amended and restated in its entirety to read as follows:

                  Section 12.12. Assignment Agreements.  (a) Each Bank shall
                  have the right at any time, with the prior consent of the
                  Agent and, so long as no Event of Default then exists, the
                  Borrower (which consent of the Borrower shall not be
                  unreasonably withheld) to sell, assign, transfer or negotiate
                  all or any part of its rights and obligations under the Loan
                  Documents (including, without limitation, the indebtedness
                  evidenced by the Notes held by such assigning Bank, together
                  with an equivalent percentage of its obligation to make Loans
                  and participate in Letters of Credit) to one or more
                  commercial banks or other financial institutions or investors,
                  provided that, unless otherwise agreed to by the Agent, such
                  assignment shall be of a fixed percentage (and not by its
                  terms of varying percentage) of the assigning Bank's rights
                  and obligations under the Loan Documents; provided, however,
                  that in order to make any such assignment (i) unless the
                  assigning Bank is assigning all of its Commitments,
                  outstanding Loans and Reimbursement Obligations, the assigning
                  Bank shall retain at least $5,000,000 in outstanding Loans,
                  interests in Letters of Credit and unused Commitments, (ii)
                  the assignee bank shall have outstanding Loans, interests in
                  Letters of Credit and unused Commitments of at least
                  $5,000,000, (iii) each such assignment shall be evidenced by a
                  written agreement (substantially in the



                                      -16-
<PAGE>   17

                  form attached hereto as Exhibit I or in such other form
                  acceptable to the Agent) executed by such assigning Bank, such
                  assignee bank or banks, the Agent and, if required as provided
                  above, the Borrower, which agreement shall specify in each
                  instance the portion of the Obligations which are to be
                  assigned to the assignee bank and the portion of the
                  Commitments of the assigning Bank to be assumed by the
                  assignee bank or banks, and (iv) the assigning Bank shall pay
                  to the Agent a processing fee of $3,500 and any out-of-pocket
                  attorneys' fees and expenses incurred by the Agent in
                  connection with any such assignment agreement. Any such
                  assignee shall become a Bank for all purposes hereunder to the
                  extent of the rights and obligations under the Loan Documents
                  it assumes and the assigning Bank shall be released from its
                  obligations, and will have released its rights, under the Loan
                  Documents to the extent of such assignment. The Borrower
                  authorizes each Bank to disclose to any purchaser or
                  prospective purchaser of an interest in the Loans and
                  Reimbursement Obligations owed to it or its Commitments under
                  this Section any financial or other information pertaining to
                  the Borrower. Promptly upon the effectiveness of any such
                  assignment agreement, the Borrower shall execute and deliver
                  replacement Notes to the assigning Bank and the assignee Bank
                  in the respective amounts of their Commitments (or assigned
                  principal amounts, as applicable) after giving effect to the
                  reduction occasioned by such assignment (all such Notes to
                  constitute "Notes" for all purposes of this Agreement and the
                  other Loan Documents) and the assigning Bank shall surrender
                  to the Borrower its old Notes.

                           (b)      Any Bank may at any time pledge or grant a
                  security interest in all or any portion of its rights under
                  this Agreement to secure obligations of such Bank, including
                  any such pledge or grant to a Federal Reserve Bank, and this
                  Section shall not apply to any such pledge or grant of a
                  security interest; provided that no such pledge or grant of a
                  security interest shall release a Bank from any of its
                  obligations hereunder or substitute any such pledgee or
                  secured party for such Bank as a party hereto; provided
                  further, however, that the right of any such pledgee or
                  grantee (other than any Federal Reserve Bank) to further
                  transfer all or any portion of the rights pledged or granted
                  to it, whether by means of foreclosure or otherwise, shall be
                  at all times subject to the terms of this Agreement.



                                      -17-
<PAGE>   18


                1.20.      Section 12.13 of the Credit Agreement shall be
         amended and restated in its entirety to read as follows:

                           Section 12.13. Amendments.   Any provision of this
                  Agreement or the other Loan Documents may be amended or waived
                  if, but only if, such amendment or waiver is in writing and is
                  signed by (a) the Borrower, (b) the Required Banks, and (c) if
                  the rights or duties of the Agent are affected thereby, the
                  Agent; provided that:

                           (i)      no amendment or waiver pursuant to this
                  Section 12.13 shall (A) increase any Commitment of any Bank
                  without the consent of such Bank or (B) reduce the amount of
                  or postpone the date for payment of any principal of or
                  interest on any Loan or of any Reimbursement Obligation or of
                  any fee payable hereunder without the consent of the Bank to
                  which such payment is owing or which has committed to make
                  such Loan or Letter of Credit (or participate therein)
                  hereunder; and

                           (ii)     no amendment or waiver pursuant to this
                  Section 12.13 shall, unless signed by each Bank, change the
                  definitions of Revolving Credit Termination Date, Term A
                  Credit Commitment Termination Date, Term A Credit Final
                  Maturity Date, Term B Credit Final Maturity Date, Term C
                  Credit Final Maturity Date, or Required Banks, change the
                  provisions of this Section 12.13, Section 7, Section 9,
                  release any guarantor or all or any substantial part of the
                  Collateral (except as otherwise provided for in the Loan
                  Documents), or affect the number of Banks required to take any
                  action hereunder or under any other Loan Document.

                 1.21.     The Credit Agreement shall be amended by adding at
         the end thereof a Schedule 1 which shall read as set forth on Schedule
         1 attached hereto and made a part hereof.

                 1.22.     Exhibit F to the Credit Agreement shall be deleted
         and a new Exhibit F-1 and Exhibit F-2 shall be inserted in lieu thereof
         which shall read as set forth on Exhibits F-1 and F-2 attached hereto.

SECTION 2.          WAIVER RELATING TO SALE OF BLOCK VISION.

         The Borrower has notified the Agent and the Banks that the Borrower
intends to sell its Subsidiary, Block Vision, Inc., on or before June 30, 1999,
for total consideration of not less than $7,000,000, of which net cash proceeds
shall not be less than $5,000,000 (the "Block Vision Sale"). The Block Vision
Sale will constitute a default under Sections 8.16 and 8.17 of the Credit
Agreement and, for that reason, the Borrower hereby requests the Banks waive



                                      -18-
<PAGE>   19

Sections 8.16 and 8.17 of the Credit Agreement to permit the Block Vision Sale
as described herein. By signing below, the Banks hereby agree to waive
compliance with Sections 8.16 and 8.17 of the Credit Agreement to permit, and
only to permit, the Block Vision Sale but only so long as (a) the Block Vision
Sale occurs on or before June 30, 1999, (b) the total consideration received by,
or for the benefit of, the Borrower or any of its other Subsidiaries in
connection with the Block Vision Sale shall be in no event be less than
$7,000,000, of which not less than $5,000,000 shall be received as net cash
proceeds from the sale thereof, (c) promptly upon, and in no event later than
the Business Day after, receipt by the Borrower or any of its Subsidiaries of
the net cash proceeds from the Block Vision Sale, the Borrower shall prepay the
Term B Loans and Term C Loans in an aggregate amount equal to 50% of the amount
of such net cash proceeds (to be applied on a ratable basis among the then
outstanding Term B Loans and Term C Loans, and thereafter applied to such Term B
Loans and Term C Loans in the inverse order of maturity) (with the balance of
such net cash proceeds to be available to the Borrower for the purpose of
financing one or more Permitted Acquisitions within 180 days of the date of such
Block Vision Sale, provided the Borrower hereby agrees that such proceeds shall
be so invested in Permitted Acquisitions only after the Term A Credit
Commitments have been fully drawn upon or otherwise cancelled), and (d) if
within 180 days of the Block Vision Sale the Borrower has not reinvested such
net cash proceeds in one or more Permitted Acquisitions, and to the extent such
net cash proceeds have not been so reinvested, the Borrower shall promptly
prepay the Term B Loans and Term C Loans in the amount of such net cash proceeds
not so reinvested (with the amount of such prepayment to be applied on a ratable
basis among the then outstanding Term B Loans and Term C Loans, and thereafter
applied to such Term B Loans and Term C Loans in the inverse order of maturity).
Any prepayments which would otherwise be applied to the Term C Loans pursuant to
this Section shall be subject to the Waivable Mandatory Term C Loan Prepayment
provisions of Section 1.9(b) of the Credit Agreement as amended hereby. The
Borrower hereby acknowledges and agrees that the Banks are relying on the
foregoing in consenting to the Block Vision Sale and non-compliance by the
Borrower with any of the terms and conditions hereof shall constitute an Event
of Default under the Credit Agreement. Except as specifically waived hereby,
Sections 8.16 and 8.17 of the Credit Agreement shall stand and remain unchanged
and in full force and effect.

SECTION 3.          CONDITIONS PRECEDENT.

         The effectiveness of this Amendment is subject to the satisfaction of
all of the following conditions precedent:

                  3.1.     The Borrower, the Agent, and each of the Banks shall
         have executed and delivered this Amendment.

                  3.2.     The Agent shall have received for each of the Banks
         replacement Revolving Notes and Term Notes evidencing the Loans made or
         to be made by such Banks in the amounts set forth on Schedule 1
         attached hereto and otherwise in compliance with the provision of
         Section 1.11 hereof.



                                      -19-
<PAGE>   20

                  3.3.     The Agent shall have received for each Bank copies of
         resolutions of the Borrower's Board of Directors authorizing the
         execution, delivery, and performance of this Amendment certified to by
         its Secretary or Assistant Secretary.

                  3.4.     Each Subsidiary shall have executed its
         acknowledgement and consent to this Amendment in the space provided for
         that purpose below.

                  3.5.     The Agent shall have received for each Bank the
         favorable written opinion of counsel to the Borrower and its
         Subsidiaries, in form and substance reasonably satisfactory to the
         Agent.

                  3.6.     Legal matters incident to the execution and delivery
         of this Amendment shall be satisfactory to the Agent and its counsel.

SECTION 4.           ASSIGNMENTS AND EQUALIZATION OF OUTSTANDING COMMITMENTS,
                     LOANS AND LETTERS OF CREDIT.

         Subject to the satisfaction of the conditions precedent set forth in
Section 2 above, Bank of Montreal and Bank One Texas, N.A. each agree to make
such purchases and sales of interests in the Credit Agreement and the Loan
Documents between themselves so that from and after the date of this Amendment
each such Bank's Revolving Credit Commitment (and corresponding Percentage of
outstanding Revolving Credit Loans and L/C Obligations), Term A Loan Commitment
(and corresponding Percentage of outstanding Term A Loans), and interest in the
outstanding Term B Loans after giving effect this Amendment shall be as set
forth on Schedule 1 attached hereto. Such purchases and sales shall be arranged
through the Agent and each such Bank hereby agrees to execute such further
instruments and documents, if any, as the Agent may reasonably request in
connection therewith.

SECTION 5.           REPRESENTATIONS.

         In order to induce the Banks to execute and deliver this Amendment, the
Borrower hereby represents to the Agent and the Banks that as of the date hereof
the representations and warranties set forth in Section 6 of the Credit
Agreement are and shall be and remain true and correct (except that the
representations contained in Section 6.5 shall be deemed to refer to the most
recent financial statements of the Borrower delivered to the Banks) and the
Borrower and its Subsidiaries are in compliance with all of the terms and
conditions of the Credit Agreement and the other Loan Documents and no Default
or Event of Default has occurred and is continuing or shall result after giving
effect to this Amendment.

SECTION 6.           MISCELLANEOUS.

        6.1.      The Borrower has heretofore executed and delivered to the
Agent and the Banks certain of the Collateral Documents. The Borrower hereby
acknowledges and agrees that, notwithstanding the execution and delivery of this
Amendment, the Collateral Documents remain in full force and effect and the
rights and remedies of the Agent and the Banks thereunder, the



                                      -20-
<PAGE>   21

obligations of the Borrower thereunder, and the liens and security interests
created and provided for thereunder remain in full force and effect and shall
not be affected, impaired, or discharged hereby. The Borrower hereby
acknowledges and agrees that the Loans as modified by this Amendment constitute
Obligations secured by each of the Collateral Documents. Nothing herein
contained shall in any manner affect or impair the priority of the liens and
security interests created and provided for by the Collateral Documents as to
the indebtedness which would be secured thereby prior to giving effect to this
Amendment.

        6.2.      Except as specifically amended herein, the Credit Agreement
shall continue in full force and effect in accordance with its original terms.
Reference to this specific Amendment need not be made in the Credit Agreement,
the Notes, or any other instrument or document executed in connection therewith,
or in any certificate, letter or communication issued or made pursuant to or
with respect to the Credit Agreement, any reference in any of such items to the
Credit Agreement being sufficient to refer to the Credit Agreement as amended
hereby.

        6.3.      The Borrower agrees to pay on demand all costs and expenses of
or incurred by the Agent in connection with the negotiation, preparation,
execution, and delivery of this Amendment and the other instruments and
documents to be executed and delivered in connection herewith, including the
fees and expenses of counsel for the Agent.

         6.4      This Amendment may be executed in any number of counterparts,
and by the different parties on different counterpart signature pages, all of
which taken together shall constitute one and the same agreement. Any of the
parties hereto may execute this Amendment by signing any such counterpart and
each of such counterparts shall for all purposes be deemed to be an original.
This Amendment shall be governed by the internal laws of the State of Illinois.



                           [SIGNATURE PAGES TO FOLLOW]



                                      -21-
<PAGE>   22

         This First Amendment to Amended and Restated Credit Agreement is dated
as of the date and year first above written.

                                    VISION TWENTY-ONE, INC.


                                    By
                                      Name   /s/ Richard T. Welch
                                          --------------------------------------
                                      Title      Chief Financial Officer
                                           -------------------------------------


         Accepted and agreed to as of the day and year last above written.


                                    BANK OF MONTREAL, in its individual
                                      capacity as a Bank and as Agent


                                    By
                                      Name  /s/ Irene M. Geller
                                          --------------------------------------
                                      Title     Director
                                           -------------------------------------


                                    BANK ONE TEXAS, N.A.


                                    By
                                      Name  /s/ James B. Lukowicz
                                          --------------------------------------
                                      Title     Vice President
                                           -------------------------------------


                                    PACIFICA PARTNERS I, L.P.
                                        By: Imperial Credit Asset
                                            Management, as its Investment
                                            Manager



                                    By
                                      Name  /s/ Michael J. Bacevich
                                          --------------------------------------
                                      Title     Senior Vice President
                                           -------------------------------------


                                    PILGRIM AMERICA PRIME RATE TRUST
                                        By: Pilgrim America Investments, Inc.,
                                            as its Investment Manager



                                    By
                                      Name  /s/ Charles E. Lemieux, CFA
                                          --------------------------------------
                                      Title     Assistant Vice President
                                           -------------------------------------



                                      -22-
<PAGE>   23

                                    PILGRIM AMERICA HIGH INCOME
                                       INVESTMENTS LTD.
                                         By: Pilgrim America Investments, Inc.,
                                             as its Investment Manager



                                    By
                                      Name  /s/ Charles E. Lemieux, CFA
                                          --------------------------------------
                                      Title     Assistant Vice President
                                           -------------------------------------


                                    MERRILL LYNCH BUSINESS FINANCIAL
                                       SERVICES, INC.



                                    By
                                      Name  /s/ Thaddeus Murphy
                                          --------------------------------------
                                      Title     Assistant Vice President
                                           -------------------------------------



                                      -23-
<PAGE>   24

                           ACKNOWLEDGEMENT AND CONSENT

         The undersigned, being all of the Material Subsidiaries of Vision
Twenty-One, Inc., have heretofore executed and delivered to the Agent and the
Banks one or more Guaranties and Collateral Documents. Each of the undersigned
hereby consents to the Amendment to the Credit Agreement as set forth above and
confirms that its Guaranty and Collateral Documents, and all of its obligations
thereunder, remain in full force and effect and, without limiting the foregoing,
acknowledges and agrees that the Loans as modified therein constitute
Obligations guaranteed by, or otherwise secured by, the Loan Documents executed
by it. Each of the undersigned further agrees that the consent of the
undersigned to any further amendments to the Credit Agreement shall not be
required as a result of this consent having been obtained, except to the extent,
if any, required by the Loan Documents referred to above.

                                    "GUARANTORS"

                                    VISION 21 PHYSICIAN PRACTICE
                                      MANAGEMENT COMPANY
                                    VISION 21 OF SOUTHERN ARIZONA, INC.
                                    VISION 21 OF SIERRA VISTA, INC.
                                    VISION 21 MANAGEMENT SERVICES, INC.
                                    VISION 21 MANAGED EYE CARE OF TAMPA
                                      BAY, INC.
                                    VISION TWENTY-ONE MANAGED EYE CARE
                                      IPA, INC.
                                    BBG-COA, INC.
                                    BLOCK VISION, INC.
                                    UVC INDEPENDENT PRACTICE ASSOCIATION,
                                      INC.
                                    MEC HEALTH CARE, INC.
                                    LSI ACQUISITION, INC.
                                    VISION TWENTY-ONE EYE SURGERY CENTERS,
                                      INC.
                                    EYE SURGERY CENTER MANAGEMENT, INC.
                                    VISION TWENTY-ONE REFRACTIVE CENTER,
                                      INC.
                                    VISION TWENTY-ONE OF WISCONSIN, INC.


                                    By  /s/ Richard T. Welch
                                      ----------------------------------
                                      Richard T. Welch, an authorized signatory
                                      for each of the above-referenced entities



                                      -24-
<PAGE>   25

                                   SCHEDULE 1

                AGGREGATE COMMITMENTS AND OUTSTANDING TERM LOANS


<TABLE>
<CAPTION>
                             Revolving Credit      Term A Loan         Outstanding         Outstanding
Name of Bank                    Commitment         Commitment          Term B Loan         Term C Loan
------------                    ----------         -----------         -----------         -----------

<S>                          <C>                   <C>                 <C>                 <C>
Bank of Montreal                $5,250,000         $ 8,750,000         $ 9,000,000         $25,000,000

Bank One,                       $2,250,000         $ 3,750,000         $ 6,000,000         $         0
Texas, N.A.

Pacifica Partners I,            $        0         $         0         $         0         $10,000,000
L.P.

Pilgrim America Prime           $        0         $         0         $         0         $ 5,000,000
Rate Trust

Pilgrim America High            $        0         $         0         $         0         $ 5,000,000
Income Investments Ltd.

Merrill Lynch                   $        0         $         0         $ 5,000,000         $ 5,000,000
Business Financial
Services, Inc.
                                ----------         -----------         -----------         -----------

          Totals                $7,500,000         $12,500,000         $20,000,000         $50,000,000
</TABLE>


<PAGE>   26

                                   EXHIBIT F-1


                                   TERM B NOTE

U.S. $_______________                                    ________________, 19___

         FOR VALUE RECEIVED, the undersigned, VISION TWENTY-ONE, INC., a Florida
corporation (the "Borrower"), hereby promises to pay to the order of ___________
__________________ (the "Bank") at the principal office of Bank of Montreal, as
Agent, in Chicago, Illinois, in immediately available funds, the principal sum
of ___________________ Dollars ($__________) or, if less, the aggregate unpaid
principal amount of the Term B Loan made or maintained by the Bank to the
Borrower pursuant to the Credit Agreement, in consecutive quarter-annual
principal installments in the amounts called for by Section 1.8(c) of the Credit
Agreement, commencing on September 30, 2000, and continuing on the last day of
each December, March, June, and September occurring thereafter, together with
interest on the principal amount of such Term B Loan from time to time
outstanding hereunder at the rates, and payable in the manner and on the dates,
specified in the Credit Agreement, except that all principal and interest not
sooner paid on the Term B Loan evidenced hereby shall be due and payable on the
Term B Credit Final Maturity Date.

         The Bank shall record on its books or records or on a schedule attached
to this Note, which is a part hereof, the Term B Loan made or maintained by it
pursuant to the Credit Agreement, together with all payments of principal and
interest and the principal balances from time to time outstanding hereon,
whether the Term B Loan is a Base Rate Loan or a Eurodollar Loan, the interest
rate and Interest Period applicable thereto, provided that prior to the transfer
of this Note all such amounts shall be recorded on a schedule attached to this
Note. The record thereof, whether shown on such books or records or on a
schedule to this Note, shall be prima facie evidence of the same, provided,
however, that the failure of the Bank to record any of the foregoing or any
error in any such record shall not limit or otherwise affect the obligation of
the Borrower to repay the Term B Loan made to it pursuant to the Credit
Agreement together with accrued interest thereon.

         This Note is one of the Term B Notes referred to in the Amended and
Restated Credit Agreement dated as of July 1, 1998, among the Borrower, Bank of
Montreal, as Agent, and the Banks party thereto (the "Credit Agreement"), and
this Note and the holder hereof are entitled to all the benefits and security
provided for thereby or referred to therein, to which Credit Agreement reference
is hereby made for a statement thereof. All defined terms used in this Note,
except terms otherwise defined herein, shall have the same meaning as in the
Credit Agreement. This Note shall be governed by and construed in accordance
with the internal laws of the State of Illinois.

         Voluntary prepayments may be made hereon, certain prepayments are
required to be made hereon, and this Note may be declared due prior to the
expressed maturity hereof, all in the events, on the terms and in the manner as
provided for in the Credit Agreement.


<PAGE>   27

         The Borrower hereby waives demand, presentment, protest or notice of
any kind hereunder.

                                    VISION TWENTY-ONE, INC.


                                    By
                                      Name
                                          --------------------------------------
                                      Title
                                           -------------------------------------



                                      -2-


<PAGE>   28

                                   EXHIBIT F-2


                                   TERM C NOTE

U.S. $_______________                                    ________________, 19___

         FOR VALUE RECEIVED, the undersigned, VISION TWENTY-ONE, INC., a Florida
corporation (the "Borrower"), hereby promises to pay to the order of____________
___________________ (the "Bank") at the principal office of Bank of Montreal, as
Agent, in Chicago, Illinois, in immediately available funds, the principal sum
of ___________________ Dollars ($__________) or, if less, the aggregate unpaid
principal amount of the Term C Loan made or maintained by the Bank to the
Borrower pursuant to the Credit Agreement, in consecutive annual principal
installments in the amounts called for by Section 1.8(d) of the Credit
Agreement, commencing June 30, 1999, and continuing on the last day of each June
occurring thereafter, together with interest on the principal amount of such
Term C Loan from time to time outstanding hereunder at the rates, and payable in
the manner and on the dates, specified in the Credit Agreement, except that all
principal and interest not sooner paid on the Term C Loan evidenced hereby shall
be due and payable the Term C Credit Final Maturity Date.

         The Bank shall record on its books or records or on a schedule attached
to this Note, which is a part hereof, the Term C Loan made or maintained by it
pursuant to the Credit Agreement, together with all payments of principal and
interest and the principal balances from time to time outstanding hereon,
whether the Term C Loan is a Base Rate Loan or a Eurodollar Loan or a Fixed Rate
Loan, the interest rate and Interest Period applicable thereto, provided that
prior to the transfer of this Note all such amounts shall be recorded on a
schedule attached to this Note. The record thereof, whether shown on such books
or records or on a schedule to this Note, shall be prima facie evidence of the
same, provided, however, that the failure of the Bank to record any of the
foregoing or any error in any such record shall not limit or otherwise affect
the obligation of the Borrower to repay the Term C Loan made to it pursuant to
the Credit Agreement together with accrued interest thereon.

         This Note is one of the Term C Notes referred to in the Amended and
Restated Credit Agreement dated as of July 1, 1998, among the Borrower, Bank of
Montreal, as Agent, and the Banks party thereto (the "Credit Agreement"), and
this Note and the holder hereof are entitled to all the benefits and security
provided for thereby or referred to therein, to which Credit Agreement reference
is hereby made for a statement thereof. All defined terms used in this Note,
except terms otherwise defined herein, shall have the same meaning as in the
Credit Agreement. This Note shall be governed by and construed in accordance
with the internal laws of the State of Illinois.

         Voluntary prepayments may be made hereon, certain prepayments are
required to be made hereon, and this Note may be declared due prior to the
expressed maturity hereof, all in the events, on the terms and in the manner as
provided for in the Credit Agreement.


<PAGE>   29

         The Borrower hereby waives demand, presentment, protest or notice of
any kind hereunder.

                                    VISION TWENTY-ONE, INC.


                                    By
                                      Name
                                          --------------------------------------
                                      Title
                                           -------------------------------------



                                      -2-