Dexamethasone Implant Produces Better Outcomes than Oral Acetazolamide in Patients with Cystoid Macular Edema Secondary to Retinitis Pigmentosa

Purpose: To compare the clinical outcome of intravitreal dexamethasone implant versus oral acetazolamide in patients with cystoid macular edema (CME) secondary to retinitis pigmentosa (RP). Design: Multicenter, prospective, propensity-score-matched, comparative study. Methods: Eyes with RP and CME were treated either with intravitreal dexamethasone implant or with oral acetazolamide (500 mg/day). Patients were evaluated monthly and followed up for 12 months. Primary outcome measures were changes in central retinal thickness and best corrected visual acuity (BCVA). Adverse events were recorded. Results: Propensity score matching resulted in 2 groups of 30 eyes each. All patients completed 12 months of follow-up. Mean central retinal thickness decreased from 535 μm at baseline to 208 μm at month 12 in the dexamethasone implant group and from 519 to 339 μm in the oral acetazolamide group (P < 0.001, Student's t-test). Mean BCVA average change from baseline during the study (area-under-the-curve approach) was -0.084 logarithm of the minimum angle of resolution (logMAR) (+4.2 letters) in the dexamethasone implant group and -0.032 (+1.6 letters) in the oral acetazolamide group (P < 0.05, Mann-Whitney U test). Patients in the dexamethasone implant group required on average 1.7 treatments during 1 year of therapy. Conclusions: In this study, intravitreal dexamethasone implant produced better anatomic and functional improvements over oral acetazolamide in patients affected by CME secondary to RP. Larger, randomized clinical trials with longer follow-up are warranted to confirm these data.