Fig. 1

The periarterial capillary-free zone (paCFZ) areas, artery areas and paCFZ area to artery area (P/A) ratio of the first-order (a–c) and second-order (d–f) arteries in the unaffected quadrants of branch retinal vein occlusion (BRVO) eyes at baseline and 3, 6 and 12 months after intravitreal ranibizumab (IVR) injections. Before treatment, the BRVO eyes demonstrated significantly larger paCFZ areas (P < 0.01, P < 0.01), paCFZ/artery (P/A) ratios (P < 0.01, P < 0.01) of the first-order (a, c) and second-order (d, f) arteries compared with the fellow eyes, while the corresponding artery areas (b, e) did not show significant difference, respectively (P = 0.20, P = 0.25). After IVR injections, the paCFZ areas (P < 0.01, P < 0.01) and P/A ratios (P < 0.01, P < 0.01) demonstrated remarkable decreases in the first-order (a, c) and second-order (d, f) arteries. Pairwise comparisons between baseline and 3, 6, and 12 months after treatment revealed significant reductions in the paCFZ areas (all P < 0.01) and P/A ratios (all P < 0.01) of the first-order (a, c) and the second-order (d, f) arteries. The paCFZ areas and P/A ratios returned almost to the levels of the healthy fellow eyes (a, c, d, f). However, the artery areas were not significantly decreased in the first-order artery (b, P = 0.05) or the second-order artery (e, P = 0.20), respectively. *P < 0.05