Choroidal Vascularity Index and Treatment Outcomes in Branch Retinal Vein Occlusion Patients with Macular Edema

Purpose: To explore the association between the visual and anatomical outcomes and the choroidal vascularity index (CVI) post-intravitreal injection in patients with macular edema associated with branch retinal vein occlusion (BRVO).Methods: We conducted a retrospective review of medical records of 50 patients (27 eyes treated with anti-vascular endothelial growth factor and 23 eyes treated with a dexamethasone implant) with BRVO and macular edema who underwent intravitreal injections from January 2017 to October 2020. We measured the central macular thickness (CMT), subfoveal choroidal thickness, and CVI of the BRVO eyes and the fellow eyes using optical coherence tomography and then analyzed the correlation between these measurements and visual and anatomical outcomes.Results: After six months of treatment, the best corrected visual acuity improved, and CMT decreased. Multiple linear regression analysis revealed that factors associated with best corrected visual acuity improvement at six months were fellow eye CVI (standardized β = 0.346, p = 0.008), ellipsoid zone integrity (standardized β = 0.398, p = 0.001), and initial best corrected visual acuity (standardized β = 0.590, p < 0.001). Initial CMT (standardized β = 0.563, p < 0.001) was the only factor associated with the decrease in CMT at six months.Conclusions: In cases of severe macular edema, accurate evaluation of choroidal vessels can be challenging due to shadowing. We discovered that a larger CVI in the fellow eye was associated with greater visual improvement in patients with BRVO and macular edema. CVI could be a prognostic factor for predicting treatment outcomes in BRVO patients, suggesting that the choroidal vascular status may play a role in the pathophysiology of BRVO.