Role of the Choroidal Vascularity Index in Branch Retinal Vein Occlusion with Macular Edema

Abstract

The purpose of this study was to assess choroidal vasculature changes in eyes with branch retinal vein occlusion (BRVO) and macular edema (ME) using the choroidal vascularity index (CVI) and evaluate the effectiveness of CVI as a prognostic biomarker. 35 patients (70 eyes) with BRVO and ME were analyzed retrospectively. Luminal and stromal areas in choroids of swept-source optical coherence tomography were calculated using the image binarization technique. The CVI was calculated as the ratio of the luminal to total choroidal area. The CVI of BRVO and ME eyes were compared with that of the unaffected fellow and post anti-vascular endothelial growth factor (VEGF) injected eyes. A regression analysis was performed on the choroidal parameters and logMAR visual acuity (VA) two years post disease onset. The CVI of BRVO and ME eyes was significantly lower than the fellow and post-injected eyes (p<0.05). The regression analysis showed a strong association between two years after logMAR VA and the CVI of fellow eyes (R2=0.433, p<0.001). No remarkable R2 values were observed in the CVI and subfoveal choroidal thickness of BRVO and ME eyes (R2=0.189, 0.155, respectively, p<0.05). Reduced CVI in BRVO and ME suggests that retinal ischemia and choroidal vascular changes might be closely related. The fellow eye CVI could be a useful supplementary prognostic biomarker.