Quantitative Analysis of Microvascular Network with Optical Coherence Tomography Angiography and its Correlation with Visual Acuity in Retinal Vein Occlusion

Purpose: To analyze the macular microvascular network and the correlations between visual acuity and quantitative parameters using optical coherence tomography angiography (OCTA) in eyes with retinal vein occlusion (RVO). Methods: We conducted a prospective cross-sectional study including patients with unilateral RVO. We performed 4.5 mm x 4.5 mm macular OCTA angiograms for assessment of quantitative parameters in both superficial and deep capillary plexuses (SCP, DCP). Area of foveal avascular zone (FAZ), vascular density (VD), skeleton density (SD), fractal dimension (FD), vessel diameter index (VDI), and lacunarity (LAC) were analyzed. Results: Seventy eyes of 35 patients were enrolled. As compared to fellow eyes, OCTA analysis in eyes with RVO showed larger FAZ, lower VD, lower SD, lower FD, higher VDI, and increased LAC in both plexuses (All P < 0.05). The enlargement of FAZ in the SCP was associated with visual loss (P = 0.025, r = 0.378). In the DCP, visual acuity was negatively correlated with parafoveal VD, SD, and FD (P = 0.004, r = -0.472; P = 0.003, r = -0.482 and P = 0.036, r = -0.308, respectively). Stepwise multivariate regression analysis showed that lower SD and lower FD in the DCP remained correlated with poorer visual acuity (P = 0.04, r = -0.261 and P = 0.032, r = -0.264, respectively). Conclusions: OCTA provides quantitative parameters to analyze retinal microvasculature in eyes with RVO. These OCTA biomarkers could be used to predict the impact of macular ischemia and capillary dropout on visual acuity in RVO.