VITREORETINAL TOXICITY OF ACETAZOLAMIDE FOLLOWING INTRAVITREAL ADMINISTRATION IN THE RABBIT EYE

Acetazolamide, a carbonic anhydrase inhibitor, has been shown effectiv e in the treatment of cystoid macular edema; however, chronic use of t he drug is limited by its serious systemic side effects. Intraocular a dministration can eliminate these systemic complications. We evaluated vitreoretinal toxicity after intravitreal injection of acetazolamide in the rabbit eye. The right eye of each rabbit received a single acet azolamide injection; the left eye received balanced salt solution and served as a control. The effect of the drug was evaluated by clinical observation, electroretinography, and histopathologic study. Intravitr eal injection of up to 0.5 mg acetazolamide did not cause vitreoretina l toxicity. Injection of 1 mg or higher doses depressed the b-wave amp litude of electroretinograms and damaged the outer segments of the pho toreceptors, as determined by light and electron microscopy.