Evaluation of Microvascular Network with Optical Coherence Tomography Angiography (OCTA) in Branch Retinal vein Occlusion (BRVO)
Abstract Purpose: To evaluate changes of microvascular network of macular and peripapillary regions and to provide a quantitative measurement of foveal avascular zone (FAZ) in unilateral BRVO patients. Methods: Forty-seven unilateral BRVO patients were enrolled. A 3*3 mm scan centered on fovea followed by a 4.5*4.5 mm scan centered on optic nerve head (ONH) were obtained in BRVO eyes and fellow eyes of each individual using OCTA (Optovue Inc., Fremont, CA, USA). Vessel density (VD) in superficial (SVC) and deep vascular complex (DVC) of macula and radial peripapillary capillary (RPC) were automatically calculated. Parameters of FAZ region including size, perimeter, acircularity index (AI) and foveal density 300 (FD-300) were measured. Results: VDs of SCV and DVC were significantly lower, especially in affected regions, in BRVO eyes compared with fellow eyes ( P <0.05). BRVO affected eyes has larger FAZ size, FAZ perimeter, AI and lower FD-300 compared with fellow eyes (all P <0.05). The average vessel density in whole area and peripapillary area in BRVO eyes were significantly lower compared with fellow eyes ( P <0.05). Conclusions: OCTA provided quantitative information of vascular changes in BRVO. FAZ in BRVO eyes showed significant morphological alterations and decreases of VD in surrounding area. Decreases of VD existed not only in SVC and DVC in macular region but also in RPCs in BRVO eyes. Key words: optical coherence tomography angiography, retinal vasculature, foveal avascular zone, radial peripapillary capillary, branch retinal vein occlusion