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                                                                     Exhibit 2.2
                                 PROMISSORY NOTE


U.S.  $500,000                                                 January 14, 2000



         FOR VALUE RECEIVED, Escalon Medical Corp. with an office at 351 East
Conestoga Road, Wayne, PA 19087 ("Maker") promises to pay to the order of Louis
Katz, as Agent, with an address at 72-53 141st Street, Flushing, NY 11367
("Holder") the principal sum of $500,000. The entire principal amount of this
Note shall be due and payable 125 days from the date hereof. This Note has been
issued pursuant to Section 4.03 of that certain Stock Purchase Agreement dated
January 14, 2000 among Maker, Sonomed, Inc. and the former stockholders of
Sonomed, Inc., to which reference is made for additional terms upon which this
Note has been issued, may be adjusted and shall be repaid. This Note shall not
bear interest, except as expressly provided for herein.

         Maker may prepay this Note at any time without penalty.

         If the Maker shall default in the payment of any installment of
principal or interest under this Note, interest shall accrue on all amounts
payable hereunder that are not paid when due at a rate per annum equal to 10%
(the "Post-Default Rate") and shall be payable on demand.

         In the event that interest in excess of the maximum lawful rate of
interest under applicable law shall be paid to Maker hereunder, the excess
interest amount shall promptly be refunded to Maker.

         Maker hereby waives presentment, demand, notice, protest and all other
demands and notices in connection with the delivery, acceptance, performance,
default or enforcement of this Note, and assents to any extension or
postponement of the time of payment or any other forbearance or indulgence
without notice.

         All notices and payments hereunder shall be delivered personally or
sent by registered or certified mail, postage prepaid, return receipt requested,
to the parties at their respective addresses set forth above, or such other
address as may be designated form time to time by such notice.

         Maker (i) agrees that any legal suit, action or proceeding arising out
of or relating to this Note may be instituted in a court of the State of New
York, in the County of New York or the Federal Court for the Southern District
of New York and (ii) waives any objection that it may now or hereafter have to
the laying of the venue of any such suit, action or proceeding in any such
venue. Further, Maker agrees that the mailing of any process in any suit, action
or proceeding in accordance with the notice provisions of this Note shall
constitute personal service thereof.




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         If a default occurs, Holder may declare this Note to be immediately due
and payable and exercise any and all remedies available to him under law. If
suit is brought to collect this Note, Maker agrees to pay all of Holder's costs
and expenses of collection of this Note, including but not limited to reasonable
attorneys' fees. The failure of Holder to exercise any right or remedy,
including acceptance by Holder of a partial or delinquent payment, shall not
constitute a waiver of any obligation of Maker or right of Holder, or constitute
a waiver of any other similar default occurring subsequently. Maker hereby
consents that at any time, or from time to time, payments of any sum payable
under this Note may be extended without notice whether for a definite or
indefinite time and without affecting Maker's liability hereunder.

         This Note may be assigned by Maker to, and Maker's obligations under
this Note may be assumed by, Maker's wholly owned subsidiary, Sonomed, Inc.,
provided that (a) Maker and Sonomed, Inc. shall execute and deliver to the Agent
an instrument of assignment and assumption reasonably satisfactory to the Agent,
and (b) Maker shall remain jointly and severally liable for all obligations of
Maker hereunder.

         This Note shall be governed by the laws of the State of New York.


                                                ESCALON MEDICAL CORP.


                                                By: /S/ Richard J. DePiano
                                                   ---------------------------

                                                Title: Chief Executive Officer
                                                      ------------------------



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