Purpose: To study the detailed process of macular edema (ME) absorption after grid laser photocoagulation in patients with branch retinal vein occlusion (BRVO). The influence of pretreatment serous retinal detachment (SRD) at the fovea on patient outcome was also evaluated.
Design: Retrospective, interventional, comparative case series.
Participants: Thirty-seven BRVO patients presenting with severe ME.
Methods: Patients were treated with grid laser photocoagulation with 6 months of follow-up examinations. Baseline and post-treatment examinations included measurements of visual acuity (VA), fluorescein angiography, and detailed imaging of ME by optical coherence tomography (OCT). Macular thickness was defined as the distance from the inner retinal surface to the outer border of the sensory retina (foveal retinal thickness) and also to the inner border of the retinal pigment epithelium including the SRD (total foveal elevation).
Main outcome measures: Post-treatment macular thickness with OCT, VA converted to the logarithm of the minimum angle of resolution, and absorption of SRD, and correlations of macular thickness and VA both before and after treatment.
Results: Total foveal elevation and VA were significantly improved at 1, 3, and 6 months after treatment. There was also a significant correlation between reduction of total foveal elevation and increase in VA. Fourteen eyes (37.8%) displayed SRD, as evidenced by OCT at the baseline. In eyes without SRD, foveal retinal thickness and VA had significantly improved in a time-dependent manner. However, although SRD itself was almost absorbed 6 months after treatment, the improvement of both VA and total foveal elevation in eyes with pretreatment SRD was not significant compared with baseline conditions. Both post-treatment total foveal elevation and VA of eyes with SRD tended to be worse than eyes without SRD.
Conclusion: The presence of subfoveal SRD retards the absorption of ME and recovery of VA after grid laser photocoagulation in patients with BRVO.