Quantitative assessment of macular microvasculature and radial peripapillary capillary plexus in the fellow eyes of patients with retinal vein occlusion using OCT angiography

To evaluate the macular microvasculature and radial peripapillary capillary (RPC) plexus in the fellow eyes of patients diagnosed with unilateral retinal vein occlusion (RVO), using optical coherence tomography angiography (OCTA).Seventy-two fellow eyes of patients with unilateral RVO and 74 healthy control eyes were consecutively enrolled. All subjects underwent a complete ophthalmological assessment, including optical coherence tomography (OCT) and OCTA measurements. Foveal avascular zone (FAZ) area, macular vessel density (VD), and perfusion density (PD) of the superficial capillary plexus (SCP) were measured. The perfusion and flux index (FI) of the RPC plexus were measured using a 4.5mm×4.5mm ONH angiography scan acquisition protocol.The mean macular ganglion cell-inner plexiform layer (GC-IPL), and retinal nerve fibre layer (RNFL) in the inferior quadrant were significantly thinner in the fellow eyes of RVO patients compared to control eyes (P=0.010 and P=0.043, respectively). The mean macular VD in the outer ring was significantly lower in fellow eyes of RVO patients compared to control eyes (P=0.027). The mean RPC perfusion showed no significant difference between fellow eyes of RVO patients and control eyes in the four quadrants (P>0.05, all). The mean peripapillary global, inferior and nasal FI were significant lower in the fellow eyes of RVO patients compared to control eyes (P=0.033, P=0.008, P=0.009, respectively).In the fellow eyes of RVO patients, macular VD was significantly lower in the outer region, and peripapillary structural and microvascular alterations were remarkable in the inferior quadrant. The results of this study showed that the presence of RVO might be related to retinal microvasculature changes in both the macular and peripapillary regions of the unaffected fellow eyes.