Comparison of Retinal Layer Thickness and Vascular Density between Acute and Chronic Branch Retinal Vein Occlusion

PURPOSE: To compare retinal layer thickness and chorioretinal vascular density (VD) between acute and chronic branch retinal vein occlusion (BRVO). METHODS: This study included patients with BRVO. The VD of the superficial capillary plexus (VDs), the VD of the deep capillary plexus (VDd), and VD of the choriocapillaris were obtained using optical coherence tomography angiography. Acute and chronic BRVO data were compared to assess differences between the involved and uninvolved areas. RESULTS: We included 17 eyes with acute BRVO and 23 eyes with chronic BRVO. The VDs in the involved area were not significantly different between the involved area and in the uninvolved area in acute BRVO (p = 0.551). However, the difference was significant in chronic BRVO (p = 0.013). The VDd in the involved area was lower than in the uninvolved area in both acute and chronic BRVO (p = 0.020, p = 0.003, respectively). In addition, the VD of the choriocapillaris values did not differ significantly between acute and chronic BRVO, or between involved and uninvolved areas. The VDs in the involved area in chronic BRVO were lower than in acute BRVO (p = 0.047), and the VDd did not differ between acute and chronic BRVO in all areas. CONCLUSIONS: Vascular impaired patterns in the retinal layer differed between acute and chronic BRVO. These results may suggest that vascular change and remodeling develops differently in acute and chronic phases in BRVO.