Retinal microstructural disorganization in persistent macular edema secondary to branch retinal vein occlusion: an adaptive optics OCT study.

Persistent macular edema (ME) secondary to branch retinal vein occlusion (BRVO) may show a limited anatomical response to anti-vascular endothelial growth factor (VEGF) therapy despite apparent control of vascular leakage. In this non-interventional observational study, we examined whether retinal microstructural alterations beneath foveal cystoid spaces are associated with anatomical characteristics of persistent macular edema following standard anti-vascular endothelial growth factor therapy. Thirty eyes of 30 patients with persistent BRVO-related ME (≥ 6 months after onset) underwent adaptive optics optical coherence tomography (AO-OCT). Retinal microstructural organization and ellipsoid zone (EZ) integrity beneath the foveal cystoid space were evaluated, and anatomical response was assessed by the reduction in central subfield thickness (CST) after the final anti-VEGF injection. Eyes with retinal microstructural disorganization showed significantly smaller CST reductions than those with preserved retinal alignment (P = 0.019). Microstructural disorganization was also associated with greater EZ disruption (P < 0.001) and a lower density of high-intensity dots in the outer nuclear layer (P = 0.009). In contrast, macular vessel density reduction assessed by OCT angiography was not significantly associated with CST reduction. These findings suggest that retinal microstructural integrity beneath foveal cystoid spaces is associated with the anatomical response to anti-VEGF therapy in persistent BRVO-related ME.