Impact of anti-VEGF treatment-free interval during the first year on 5-year outcomes in eyes with branch retinal vein occlusion

Objectives This study aims to analyze the impact of longest treatment-free interval (TFI) between anti-vascular endothelial growth factor (anti-VEGF) injections during the first year of treatment on 5-year best-corrected visual acuity (BCVA) and recurrence of macular edema (ME) in eyes with ME secondary to branch retinal vein occlusion (BRVO). Methods A retrospective study including eyes with BRVO, minimum of 5-year follow-up, and available optical coherence topography (OCT) scans. Eyes underwent anti-VEGF loading dose therapy and were treated and monitored with an OCT-guided PRN regimen. Those with a history of ocular comorbidities were excluded. Results Total of 60 patient eyes, with 40 females and average age of 71.75 ± 11.07 years. TFI among eyes was 1 month (20%); > 1–2 months (23%); > 2–3 months (18%); > 3–4 months (17%), and >4 months (22%). Forty-three (72%) eyes experienced ME recurrence during the five-year period. Multivariate linear regression shows that TFI (−0.02 [-0.03–0.00], p = 0.021) and baseline BCVA (0.37 [0.08–0.66], p = 0.014) are significant predictors of 5-year BCVA. TFI (Cox Proportional Hazard Ratio 1.34 [1.04–1.72], p = 0.023) and number of injections in the first year (Cox Proportional Hazard Ratio 1.76 [1.01–3.06], p = 0.045) were significant predictors of ME recurrence. Gender, age, type of injection, BCVA, and CMT did not influence recurrence. Conclusion For eyes receiving anti-VEGF injections to treat ME secondary to BRVO, TFI is a significant predictor of 5-year BCVA and ME recurrence according to regression models. This study suggests more ME recurrence may be due to increased TFI or indicate more injections needed to treat severe BRVO.