Distribution of leakage index using ultra-widefield fluorescein angiography in patients with non-ischemic branch retinal vein occlusion and its association with macular edema

Background: To investigate the distribution of leakage index in patients with non-ischemic branch retinal vein occlusion (BRVO) and its correlation with the severity of macular edema. Methods: Retrospective observational study. Forty-five eyes of 45 patients with BRVO were included. Late ultra-widefield fluorescein angiography images of the affected eyes were processed and analyzed for their leakage index using Fiji software. The visible panretinal area was further divided into the peri-macular area (PMA), near-peripheral area (NPA), midperipheral area (MPA), and far-peripheral area (FPA). The relationship between the leakage index and central retinal thickness (CMT) was analyzed for the panretina and each subregion. Results: The median (interquartile range) leakage indexes of the panretina, PMA, NPA, MPA, and FPA were 5.532% (7.667%), 23.127% (26.073%), 8.303% (16.807%), 1.588% (6.204%), and 0.408% (2.215%), respectively, with a mean CMT of 552.800 +/- 183.335 mu m. The CMT was positively correlated with the leakage index in the panretina, PMA, NPA, MPA and FPA (r = 0.468, 0.426, 0.463, 0.447, 0.320, respectively; all p < 0.05). Conclusions: The leakage index in non-ischemic BRVO patients is associated with macular edema severity. The leakage index has the potential to be a useful indicator for monitoring and guiding treatment of macular edema in BRVO patients.