Efficacy of dorzolamide to reduce retinal thickness after photocoagulation, in diabetic macular edema1

AbstractBackgroundFocal photocoagulation interrupts vascular leakage in diabetic macular oedema, and allows the retinal pigment epithelium to withdraw fluid that thickens the retina; this mechanism could be enhanced by dorzolamide, a topical carbonic anhydrase inhibitor.ObjectiveTo determine the efficacy of dorzolamide compared to placebo, in reducing retinal thickness after focal photocoagulation in eyes with diabetic macular oedema.Material and methodsExperimental, comparative, prospective, longitudinal, double blind study in diabetics with focal macular oedema treated with photocoagulation. Treated eyes were randomly assigned three weeks after the procedure to receive dorzolamide (group 1) or placebo (group 2), three times daily for three weeks. Means of visual acuity, centre point thickness and macular volume were compared 3 and 6 weeks after photocoagulation within groups (Wilcoxon t) and between groups (Mann-Whitney-U).ResultsSixty-nine eyes form patients aged 58.3 ± 8.3 years; 37 were assigned to group 1 and 42 to group 2. Mean centre point thickness changed from 178.4 ± 34μm to 170 ± 29.1μm in group 1 (p = 0.04), and from 179.2 ± 22.4μm to 178.6 ± 20.8μm in group 2 (p = 0.07); mean macular volume changed from 7.63 ± 0.52mm3 to 7.50 ± 0.50mm3 in group 1 (p = 0.002) and from 7.82 ± 0.43mm3 to 7.76 ± 0.42mm3 in group 2 (p = 0.013).ConclusionsThe efficacy of dorzolamide was higher than that of placebo in reducing retinal thickness after focal photocoagulation in diabetics with macular oedema