Uveitis, an intraocular inflammatory disease, is the cause of about 10 percent of visual impairment in the United States. Uveitis may lead to many sight-threatening conditions, including cataract, vitreal opacities, glaucoma, and, most commonly, cystoid macular edema. Reduction of swelling or edema within the retina depends on the movement of fluid from the retina through the choroid. A number of studies indicate that this process requires active transport of fluid ions by the retinal pigment epithelium and may involve the carbonic anhydrase system. Current treatment of uveitis-associated cystoid macular edema requires the use of immunosuppressive or anti-inflammatory agents. However, many patients are either resistant or intolerant to this therapy. Recent reports suggested that acetazolamide, a carbonic anhydrase inhibitor that is used to lower intraocular pressure in some glaucoma patients, might be safe and effective in reducing uveitis-associated cystoid macular edema.