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 compared to previous visit, or a central subfield thickness 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-year 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 central subfield thickness was significantly associated with recurrent (hazard ratio 1.11, 95% CI: 1.05–1.18, P = 0.0004). Conclusion: The recurrence rate of RP-CME increased with time. A high baseline central subfield thickness value was a risk factor for recurrence.