The alterations of macular vascular density and the area of foveal avascular zone in branch retinal vein occlusion eyes

Abstract

Objective To observe the alterations of macular vascular density and the area of foveal avascular zone (FAZ) in branch retinal vein occlusion (BRVO) eyes. Methods A retrospective case-control study. Forty-five patients with unilateral BRVO and macular edema were enrolled in this study. Optical coherence tomography angiography (OCTA) was performed on the BRVO and fellow eyes. The scanning region in the macular area was 3 mm×3 mm. Macular vascular density and FAZ area in the superficial and deep retinal capillary plexi were measured in all eyes. The values of macular vascular density and FAZ area between BRVO eyes and fellow eyes, affected sector and unaffected sector were compared. Results The mean overall vascular density measured in the entire scan was lower in BRVO eyes compared with fellow eyes in both the superficial and deep capillary plexus (t=14.186, 9.468; P<0.05). The reduce degree of vascular density in the deep capillary plexus (7.65%) was higher than that in the superficial plexus (7.27%). In the superficial plexus, the vascular density was lower in the affected sector and the unaffected sector of the BRVO eyes compared with the corresponding sector in the fellow eyes (t=15.386, 9.435; P<0.05). The FAZ area enlarged in the BRVO eyes compared with the fellow eyes in the superficial capillary plexus and in the deep capillary plexus (t=3.216, 5.119; P<0.05). The degree of enlargement of FAZ area in the deep capillary plexus (0.19 mm2) was higher than that in the superficial plexus (0.11 mm2). Conclusions In eyes with BRVO, quantitative OCTA measurements confirm that vascular density decreased and FAZ area enlarged in the superficial and deep capillary plexi. The reduce degree of vascular density and enlargement degree of FAZ area in the deep capillary plexus are higher than those in the superficial plexus. Key words: Retinal vein occlusion/diagnosis; Regional blood flow; Tomography, optical coherence