There is a relatively high concentration of carbonic anhydrase in the avian and mammalian eye,1,2 as compared with other parts of the body; it appears to be located mainly in the lens and the ciliary body.1,3-6 A considerable amount of work, evidenced by ample literature, has been directed toward investigating the possible function of this enzyme in the ciliary body.7-10 The approach has been mainly through the use of carbonic anhydrase inhibitors, studying their effect on aqueous humor flow and ocular tension.11,12 The role of this enzyme in the formation of aqueous humor is not clearly understood at present.6,7,13-18 In the lens, where its concentration is about ten times as much as in the ciliary body and iris,1,6 the function of carbonic anhydrase is far less understood. Tn a recent investigation,19 great doubt was thrown on any possible function of this enzyme in