The Constrictive Action of Acetazolamide on the Iris Arteries of the Cat

Introduction It has recently been reported that the intraocular pressure of the anesthetized cat is dependent in great part on the ocular blood volume, very probably that of the ciliary processes.5This is based upon evidence regarding the correlations between steady-state eye pressure (IOP) and venous pressure (VP) of this species which could be expressed by the equation IOP= 0.82 VP+6.51.1,5 Acetazolamide has been reported, again in the cat, to lower the eye venous pressure and intraocular pressure without significantly altering the slope of their relationship (0.82 vs. 0.83). From yet other evidence, the effect of acetazolamide was concluded to be due, at least in part, to a constriction of blood vessels in the eye.2 The problem posed at the present time is the localization of the constriction. If a generalized constriction occurs on the intraocular venous vessels (thereby reducing blood volume and consequently intraocular pressure), one