Topical dorzolamide for macular edema in the early phase after vitrectomy and epiretinal membrane removal

BACKGROUND The purpose of this study was to evaluate prospectively the efficacy of a topical carbonic anhydrase inhibitor in macular edema after vitrectomy. METHODS Forty patients were included, all of whom had undergone vitrectomy combined with phacoemulsification and intraocular lens implantation for epiretinal membrane. Twenty eyes from 40 patients received topical 2% dorzolamide three times a day. The patients were followed up for at least 3 months. In this study, we evaluated the effect of dorzolamide on visual acuity, intraocular pressure, central macular thickness, and aqueous flare. RESULTS Mean logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity preoperatively and 2 weeks, 1 month, and 3 months after surgery was 0.48 ± 0.23, 0.60 ± 0.16, 0.40 ± 0.29, and 0.24 ± 0.32, respectively, in the treatment group, and 0.40 ± 0.09, 0.44 ± 0.12, 0.32 ± 0.10, and 0.16 ± 0.09, respectively, in the control group. No statistically significant difference was observed between the two groups. Mean central macular thickness preoperatively and at 2 weeks and 3 months after surgery was 572.6, 427.2, and 333.4 μm, respectively, in the treatment group, and 571.4, 485.2, and 388.4 μm, respectively, in the control group. Mean aqueous flare preoperatively, and 1 month and 3 months after surgery was 8.6, 34.2, and 23.5 photon counts per millisecond (pc/ms), respectively, in the treatment group, and 9.7, 24.7, and 23.4 pc/ms, respectively, in the control group. No statistically significant differences were observed between data from the two groups. However, statistically significant (P < 0.05) differences in mean central macular thickness at 1 month and mean aqueous flare at 2 weeks after surgery were found between the treatment group (358.8 μm, 36.8 pc/ms) and the control group (467.8 μm, 64.0 pc/ms). Differences in mean intraocular pressure preoperatively and at 2 weeks, 1 month, and 3 months after surgery were not statistically significant between the two groups. Intraocular pressure never exceeded 21 mmHg. CONCLUSION Topical dorzolamide significantly reduced mean central macular thickness at 1 month and mean aqueous flare at 2 weeks after surgery for epiretinal membrane compared with controls. Although further investigation of more cases and longer follow-up are needed, this study suggests that topical dorzolamide can be efficacious in reducing macular edema in the early phase after vitrectomy via its anti-inflammatory effect.