Baseline Superficial FAZ Disparity Is Associated With Recurrence in Branch Retinal Vein Occlusion-related Macular Edema

PURPOSE: To determine whether recurrence burden in branch retinal vein occlusion-related macular edema (BRVOME) reflects longitudinal foveal avascular zone (FAZ) enlargement or baseline inter-eye superficial microvascular disparity. METHODS: This retrospective, paired-eye longitudinal study included consecutive treatment-naïve unilateral BRVOME eyes. Optical coherence tomography angiography (OCTA) was performed at the first visit after complete resolution of ME following anti-vascular endothelial growth factor (anti-VEGF) therapy (baseline) and at 1 year. FAZ areas in superficial and deep capillary plexuses (SCP and DCP) were quantified in both BRVO and fellow eyes. Inter-eye FAZ disparity (ΔFAZ = BRVO - fellow) was calculated. Recurrence burden was defined as the number of intravitreal anti-VEGF injections during 12 months. RESULTS: Sixty-nine eyes were analyzed. SCP and DCP FAZ areas were significantly larger in BRVO than in fellow eyes at baseline and remained larger at 1 year (both p < 0.001). Longitudinal FAZ enlargement was not associated with recurrence burden. Baseline ΔSCP was independently associated with higher recurrence burden. Each 0.1-mm2 increase in baseline ΔSCP was associated with an 8% increase in recurrence burden [incidence rate ratio, 1.08; 95% confidence interval, 1.01 - 1.16; p = 0.022]. Baseline ΔDCP was not associated with recurrence frequency. CONCLUSION: Recurrence burden in BRVOME was associated with baseline superficial FAZ disparity rather than longitudinal FAZ progression. Baseline ΔSCP showed only modest discriminative ability and should be interpreted as one component of a broader microvascular risk profile rather than a standalone biomarker for recurrence prediction.