Topical dorzolamide for the treatment of cystoid macular edema in patients with retinitis pigmentosa

PURPOSE: To determine if topical dorzolamide, as observed with the use of systemic acetazolamide and methazolamide, would be effective in treating cystoid macular edema (CME) in patients with retinitis pigmentosa (RP). DESIGN: Prospective, nonrandomized clinical trial. METHODS: SETTING: Institutional. PATIENTS: Fifteen patients with CME and RP. INTERVENTION: A baseline visual acuity and optical coherence tomography (OCT) measurements were obtained in all patients. Each one of them was then treated with topical dorzolamide, three times a day, for at least four weeks in both eyes. MAIN OUTCOME MEASURES: Significant decrease in "foveal thickness" (more than 16%) and "foveal zone thickness" (more than 11%), as measured by OCT. RESULTS: Thirteen (87%) of 15 patients showed a significant decrease in retinal thickness in at least one eye after use of topical dorzolamide for at least four weeks. Five patients (33%) demonstrated improvement in both eyes. All patients, except one, who responded showed the effect within four weeks, but were monitored for a period of two to nine months (average 4.5 months). Four patients (31%) who showed an initial improvement in macular edema showed worsening with continued treatment. CONCLUSIONS: The present study documents the potential efficacy of topical dorzolamide for treating CME in patients with RP. We observed that some patients may show a "rebound phenomenon" with continued use of the medication; hence, there is a need for careful follow-up in patients being treated.