A randomized, masked, cross-over trial of acetazolamide for cystoid macular edema in patients with uveitis.

OBJECTIVE

To study the effect of acetazolamide on cystoid macular edema in patients with uveitis.

METHODS

Forty patients with chronic intermediate, posterior, or panuveitis associated cystoid macular edema were randomized into a masked, cross-over trial comparing acetazolamide versus placebo. Patients received an initial 4-week course of either acetazolamide or placebo (course A) followed by a 4-week washout period. They then received a 4-week course of the opposite study medication (course B). Primary endpoints included area of cystoid macular edema measured on late-phase views of fluorescein angiography and visual acuity.

RESULTS

Thirty-seven patients completed the trial and were available for analysis; 17 (46%) were randomized to receive acetazolamide and 20 (54%) to receive placebo during course A. Acetazolamide resulted in a 0.5-disc area (25%) decrease in cystoid macular edema over that of placebo (P = 0.01; estimated treatment effect = -0.5 disc areas; 95% confidence interval, -0.9 to -0.1). However, there was no statistically significant effect of acetazolamide on visual acuity (P = 0.61; estimated treatment effect = 0.6 letters; 95% confidence interval, -2 to 3).

CONCLUSIONS

A 4-week course of acetazolamide therapy results in a statistically significant but small decrease in cystoid macular edema in patients with chronic uveitis, and does not improve visual acuity. In contrast to previous studies in the literature, acetazolamide may have a more limited clinical benefit in patients with long-standing cystoid macular edema associated with chronic uveitis.