Topographic patterns of retinal edema in eyes with branch retinal vein occlusion and their association with macular edema recurrence

In this study, we evaluated the topographic pattern of retinal edema in eyes with macular edema (ME) secondary to branch retinal vein occlusion (BRVO) using a widefield retinal thickness map of optical coherence tomography and its association with ME recurrence. In 87 eyes with ME secondary to BRVO who were treated with anti-vascular endothelial growth factor (VEGF) injections and followed up for ≥ 1 years, 12 × 9 mm macular volume scans of swept-source optical coherence tomography (DRI-OCT Triton; Topcon Inc, Japan) were performed and retinal thickness maps were automatically generated at baseline and follow-up visits. Topographic patterns of retinal edema on the maps at baseline and 1 month after the first anti-vascular endothelial growth factor (VEGF) treatment were classified as extramacular (outside the ETDRS grid), macular (within the grid), and combined pattern and correlated with ME recurrences. Seventy-five of 87 (86.2%) eyes with BRVO ME showed combined edema at baseline. There were 4 topographic patterns of edema at 1 month following anti-VEGF injection as follows: no residual edema, extramacular only, macular only, and combined edema. In contrast to the baseline pattern, the pattern of retinal edema 1 month following anti-VEGF therapy showed significant association with 6-month recurrence, number of ME recurrences during a 1-year period, and time to first recurrence. (all P < 0.05) An automatically generated widefield retinal thickness map could be used to effectively visualize the topographic patterns of retinal edema in eyes with BRVO. The map can be used as a valuable tool for detection of retinal edema on widefield retinal areas and prediction of ME recurrence in eyes with BRVO.