Recurrence Rate of Cystoid Macular Edema with Topical Dorzolamide Treatment and its Risk Factors in Retinitis Pigmentosa

Purpose To investigate the rate of the recurrence of cystoid macular edema (CME) secondary to retinitis pigmentosa (RP) after the initiation of topical dorzolamide and the recurrence risk factors. Methods We retrospectively analyzed the data of RP patients at Kyushu University Hospital. We included patients who showed a treatment response to 1.0% topical dorzolamide. The day of treatment initiation was set as the baseline. Topical dorzolamide treatment was continued during the follow-up. The recurrence of CME (defined as a >20% increase in central subfield thickness [CST] compared to previous visit, or a CST value that exceed baseline value) was evaluated at each follow-up visit. Risk factors for RP-CME recurrence were analyzed by Cox proportional hazards modeling. A Kaplan-Meier survival analysis was used to evaluate the time to recurrent RP-CME. Results Forty RP-CME patients showed a treatment response to topical dorzolamide. During the mean 3.9-yr follow-up, 14 patients exhibited recurrence; its rate was 15.6%, 34.7%, and 48.7% at 1, 3, and 5 years, respectively. A high baseline CST was significantly associated with recurrent (HR 1.11, 95%CI: 1.05-1.18, p=0.0004). Conclusions The recurrence rate of RP-CME increased with time. A high baseline CST value was a risk factor for recurrent.