Wide-field swept-source OCT angiography of the periarterial capillary-free zone before and after anti-VEGF therapy for branch retinal vein occlusion

Abstract

Background: The aim of the study was to investigate the changes in the periarterial capillary-free zone (paCFZ) after anti-vascular endothelial growth factor (VEGF) therapy in patients with branch retinal vein occlusion (BRVO) by wide-field swept-source optical coherence tomography angiography (SS-OCTA) and assess their associations with clinical outcomes. Methods: In this retrospective observational study of 54 treatment-naïve BRVO patients with macular edema, we reviewed the findings of 12 × 12 mm2 SS-OCTA at baseline, 3, 6, and 12 months after intravitreal ranibizumab injections. The paCFZ and major retinal artery areas were measured on SS-OCTA images. The paCFZ area to artery area (P/A) ratio was calculated. Results: The paCFZ areas and P/A ratios of first- and second-order arteries were significantly greater in BRVO eyes than in contralateral eyes (all P < 0.01), but there were no differences in the first- and second-order artery areas (P = 0.20 and 0.25, respectively). The paCFZ areas and P/A ratios decreased significantly at 3, 6, and 12 months after anti-VEGF therapy (all P < 0.01). The baseline P/A ratio was significantly correlated with the baseline best-corrected visual acuity (BCVA), central retinal thickness, and their improvements at 3, 6, and 12 months (all P < 0.05). Baseline BCVA and P/A ratios of first- and second-order arteries were independently associated with the final BCVA in multivariate linear regression. Conclusions: Wide-field SS-OCTA shows that anti-VEGF therapy can lead to a significant improvement in the paCFZ parameters in BRVO. Smaller baseline P/A ratios on SS-OCTA tend to predict better visual outcomes at 12 months after anti-VEGF therapy.