Treatment Of Recurrent Macular Edema Secondary To Branch Retinal Vein Occlusion: A Pilot Study Comparing Subthreshold Grid Laser Treatment And Intravitreal Bevacizumab

Purpose Aim of the study is to compare the effects of subthreshold grid laser treatment (SGLT) and intravitreal bevacizumab injection (IVBI) for the treatment of recurrent macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods Prospective, randomized clinical trial registered at UMIN registry (number UMIN000005014). Thirty-five eyes of 35 patients were enrolled and randomly treated with micropulse diode laser (SGLT subgroup) or IVBI (IVBI subgroup) IVBI (1.25 mg) was given at baseline and then on a pre-re-nata regimen according to the presence of ME on optical coherence tomography (OCT) examination performed in scheduled monthly visits over a12-month follow-up. SGLT was administered once over the follow-up. Main Outcome Measures: Primary outcome measure was the decrease in mean central foveal thickness (CFT) on OCT during a 1-year follow-up. Secondary outcomes were the mean BCVA changes and the proportion of eyes that gained at least 15 letters (approximately 3 lines) at the 12-month examination. Results Eighteen and 17 patients were assigned to SGLT and to IVBI subgroups, respectively. At baseline, the two subgroups were similar with regard to mean duration of ME, BCVA, and CFT. At month 12, the mean CFT significantly improved from 484µm to 271µm in the IVBI subgroup, whereas it was unchanged in the SGLT subgroup. Mean BCVA changed from 0.92±0.3 (LogMAR) to 0.99±0.2 in the SGLT subgroup; in the IVBI subgroup, the mean BCVA showed a statistically significant improvement from 0.94±0.3 to 0.72±0.2. Ten patients in the IVBI subgroup (58%) and no patient in the SGLT subgroup gained at least 3 lines at the end of the follow-up. At the last examination, persistent ME was detected in all the eyes treated with SGLT, and in 5 eyes (29%) in the IVBI subgroup. Conclusions At 1-year follow-up, IVBI resulted in a significant functional and anatomical improvement whereas the SGLT failed to demonstrate a beneficial effects. The IVBI could represent a useful approach for the therapy of recurrent ME secondary to BRVO. However, studies with long-term follow-up are mandatory to confirm the preliminary results of the current pilot study.