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 mu m at baseline to 208 mu m at month 12 in the dexamethasone implant group and from 519 to 339 mu m 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.