The effects of acetazolamide on visual function in retinitis pigmentosa.

PURPOSE To study the effects of acetazolamide on central and peripheral visual function in patients with retinitis pigmentosa (RP) who showed no evidence of macular edema. METHODS Thirteen patients with retinitis pigmentosa participated in a preliminary study. Measures of central and peripheral visual function were obtained before and after an 8 wk period on acetazolamide. An additional 10 patients participated in a cross-over study. They were placed on a placebo for an 8 wk period, then on acetazolamide for a second 8 wk period. RESULTS None of the patients in the preliminary study showed significant changes in visual acuity, color vision, foveal cone pathway sensitivities, focal electroretinogram (ERG) amplitudes, or in any ERG parameter. Three patients, however, showed significant changes in visual field area and in dark-adapted thresholds. None of the patients in the cross-over study showed significant increases in visual field area. CONCLUSIONS Given the results and the reports of side-effects, it is difficult to justify using acetazolamide to improve retinal function in RP patients who show no evidence of cystoid macular edema.