<PAGE>

                                                                   Exhibit 10.23


               FIRST AMENDMENT TO REGISTRATION RIGHTS AGREEMENT

        This First Amendment to Registration Rights Agreement (this "First
Amendment"), is made by and between Optika Inc., a Delaware corporation (the
"Company") and the investors set forth on the signature page hereto (the
"Purchasers"), as of this 7th day of May, 2001. The Company and the Purchasers
are also sometimes collectively referred to herein as the "Parties" and
individually as a "Party."

        WHEREAS, the Parties, in addition to other parties set forth therein,
entered into that certain Registration Rights Agreement dated as of February 23,
2000 (the "Agreement");

        WHEREAS, the Parties now desire to amend the Agreement pursuant to the
terms and conditions set forth herein.

        NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth in the Agreement and as hereinafter set forth, and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the Parties agree as follows:

        1.  The first whereas clause of the Agreement is hereby amended in its
entirety to read as follows:

                "WHEREAS, the Company proposes to issue and sell (i) an
            aggregate of 731,851 shares of Series A Convertible Preferred Stock,
            par value $0.001 per share (the "Preferred Stock") of the Company,
            the terms of which are set forth in the Certificate of Designation
            in the form of Exhibit 2.2 to the Purchase Agreement (as defined
            below) and (ii) warrants (the "Warrants") to purchase an aggregate
            of 307,298 shares of the Company's Common Stock, par value $0.001
            per share (the "Common Stock"), the terms of which are set forth in
            the Warrant Agreement attached in the form of Exhibit 1.2(b) to the
            Purchase Agreement;"

        2.  The following is added after the fourth whereas clause in the
Agreement:

                "WHEREAS, the Company and the Purchasers have entered into that
            certain Exchange Agreement dated of even date herewith (the
            "Exchange Agreement") under which the Company will (i) issue to the
            Purchasers shares of the Series A-1 Convertible Preferred Stock,
            $0.001 par value per share, of the Company (the "Securities"), in
            exchange for the shares of Preferred Stock owned by such Purchaser,
            on a one-share for one-share basis and (ii) purchase from the
            Purchasers the Warrants for an aggregate purchase price of $0.01;

        3.  The definition of "Closing" in Section 4 of the Agreement is amended
            in its entirety to read as follows:

                "Closing" shall mean the date of the closing of the issuance of
            the securities pursuant to the Exchange Agreement.
<PAGE>

        4.  The definition of "Registrable Shares" in Section 1 of the Agreement
is amended by deleting the phrase "or pursuant to the Warrant Agreement" at the
end of such definition.

        5.  The definition of "Purchasers" in Section 1 of the Agreement is
amended in its entirety to read as follows:

                "Purchasers" shall have the meaning assigned thereto in the
            First Amendment."

        6.  The Company covenants and agrees that it will use its reasonable
efforts to take or cause to be taken, all actions and to do, or cause to be
done, all things necessary or desirable under applicable laws and regulations to
consummate the transactions contemplated by this First Amendment.

        7.  This First Amendment and all rights hereunder may not be assigned or
transferred by either Party without the prior written consent of each of the
Parties hereto.

        8.  All capitalized terms used and not otherwise defined herein shall
have the same meanings as set forth in the Agreement.

        9.  Except as expressly modified by the terms hereof, the terms and
provisions of the Agreement shall remain in full force and effect as originally
written.

        10. Signatures on this First Amendment may be communicated by facsimile
transmission and shall be binding upon the Parties transmitting the same by
facsimile transmission. If executed in counterparts, this First Amendment will
be as effective as if simultaneously executed.

                 [Remainder of Page Intentionally Left Blank]

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<PAGE>

        IN WITNESS WHEREOF, the Parties hereto have caused this First Amendment
to be duly executed by their respective authorized officers as of the day and
year first above written.


                                        OPTIKA INC.


                                        By:  /s/ Mark Ruport
                                             --------------------------
                                                 Mark Ruport
                                                 President


                                        INVESTORS:


                                        THOMAS WEISEL CAPITAL PARTNERS, L.P.

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its general partner

                                        By:  Thomas Weisel Partners Group LLC,
                                             its managing member

                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________


                                        TWP CEO FOUNDERS' CIRCLE (AI), L.P.

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its general partner

                                        By:  Thomas Weisel Partners Group LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________

                                       3
<PAGE>

                                        TWP CEO FOUNDERS' CIRCLE (QP), L.P.

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its general partner

                                        By:  Thomas Weisel Partners Group LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________


                                        THOMAS WEISEL CAPITAL PARTNERS
                                        EMPLOYEE FUND, L.P.

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its general partner

                                        By:  Thomas Weisel Partners Group LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________


                                        TWP 2000 C0-INVESTMENT FUND, L.P.

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its general partner

                                        By:  Thomas Weisel Partners Group LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________

                                       4
<PAGE>

                                        THOMAS WEISEL CAPITAL PARTNERS
                                        (DUTCH), L.P.

                                        By:  Thomas Weisel Capital Partners
                                             (Dutch) LLC, its general partner

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________


                                        THOMAS WEISEL CAPITAL PARTNERS (DUTCH
                                        II), L.P.

                                        By:  Thomas Weisel Capital Partners
                                             (Dutch) LLC, its general partner

                                        By:  Thomas Weisel Capital Partners LLC,
                                             its managing member


                                        By:  /s/ Alan B. Menkes
                                             -----------------------------------
                                             Name:______________________________
                                             Title:_____________________________


                                        RKB CAPITAL, L.P.


                                        By:  /s/ Peter Schleider
                                             -----------------------------------
                                             Name: Peter Schleider
                                             Title: General Partner


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