Retinal vein occlusion (RVO) refers to occlusion in retinal veins and manifest in various pathologies such as retinal bleeding, macular edema, and nonperfusion area. Intravitreally injecting vascular endothelial growth factor (VEGF) antibody is the first-line treatment for macular edema. Although the symptoms of macular edema resolve with treatment, low visual acuity may prolong in some patients. In this study, optical coherence tomography angiography was used to quantitatively assess superficial and deep retinal blood flows in a 3×3-mm macula after the resolution of edema in 85 eyes with branch RVO to elucidate its cause and relationship with visual acuity. The results of a multivariate analysis using the stepwise regression method showed that visual acuity was most significantly correlated with blood flow area in deep retinal layers (r²=0.33, p<0.001). Visual acuity significantly correlated with retinal blood flow area in the macula in central RVO. Subsequently, time-dependent changes in macular vascular density and the foveal avascular zone (FAZ) were observed from the baseline to 12 months after anti-VEGF therapy in 48 eyes with RVO. Results showed that macular vascular density and FAZ were stable over the 12-month period in most patients. However, vascular density in the superficial and deep retinal layers significantly decreased in 6 (13%) and 10 eyes (21%), respectively. In these eyes, the number of macular edema recurrence was significantly high and improvement in visual acuity was poor. These results demonstrate that preventing the recurrence of macular edema and maintaining macular blood flow are important for the visual prognosis of RVO.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 123: 1054-1064, 2019.