Subthreshold grid laser versus intravitreal bevacizumab as second-line therapy for macular edema in branch retinal vein occlusion recurring after conventional grid laser treatment

PURPOSE: To compare the effects of subthreshold grid laser treatment (SGLT) and intravitreal bevacizumab injection (IVBI) for the treatment of macular edema (ME) secondary to branch retinal vein occlusion (BRVO) recurring after conventional grid laser photocoagulation.

METHODS: Thirty-five eyes were considered in this prospective, randomised, interventional study and treated with micropulse diode laser (SGLT subgroup) or IVBI (IVBI subgroup). SGLT was administered once, whereas IVBI (1.25 mg) was given at baseline and then on a pro re nata regimen according to ME presence on optical coherence tomography (OCT), performed at monthly examinations over a 12-month follow-up. Primary outcome measures were the mean BCVA changes over the follow-up and the decrease in mean central foveal thickness (CFT) on optical coherence tomography (OCT). Secondary outcomes included the proportion of eyes that gained at least 15 letters (approximately three lines) at the 12-month examination.

RESULTS: Eighteen and 17 patients were assigned to SGLT and IVBI subgroups, respectively. At baseline, the subgroups were similar with regard to mean ME duration, BCVA, and CFT. At month 12, mean CFT significantly improved from 484 μm to 271 μm 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, 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 three lines.

CONCLUSION: At the 1-year follow-up, IVBI provided a significant functional and anatomical improvement, whereas SGLT failed to demonstrate any beneficial effects. IVBI might be a useful approach in the treatment of recurrent ME secondary to BRVO already treated with conventional grid laser photocoagulation. UMIN registry, number UMIN000005014, URL: http://www.umin.ac.jp/ctr/index.htm.