Visual acuity and retinal thickness outcomes following anti-VEGF therapy in RVO: influence of early vs. delayed treatment

Retinal vein occlusion (RVO) is a common cause of vision loss, treated primarily with intravitreal anti-VEGF injections. This study aimed to investigate how the timing of treatment initiation affects visual acuity and retinal thickness outcomes in patients with branch (BRVO) and central retinal vein occlusion (CRVO). A retrospective observational study was conducted involving 86 patients diagnosed with RVO (54 BRVO, 32 CRVO) and treated with anti-VEGF therapy at a single UK centre. Patients were stratified into early (≤ 28 days) and delayed (> 28 days) treatment groups based on the time from diagnosis to first injection. Visual acuity (ETDRS letters) and central retinal thickness (µm) were recorded at diagnosis, after three loading doses, and at one year. Paired t-tests were used to assess changes over time. Associations between treatment timing and outcomes were evaluated using Spearman’s rank correlation, while between-group comparisons were performed using Mann–Whitney U and chi-square tests. BRVO patients had significant VA gains at three injections (mean + 13.2 letters, p < 0.001) and at one year (p = 0.0002), while CRVO patients showed a non-significant trend toward improvement (p = 0.081). CRT reductions were significant in both CRVO and BRVO at three injections and at one year (p < 0.001). Earlier treatment (≤ 28 days) was weakly correlated with greater CRT reduction in CRVO (p = 0.047), but no significant association was found between treatment timing and VA change or likelihood of > 15-letter improvement in either group. While early treatment led to short-term visual and anatomical gains, long-term visual outcomes at one year were not significantly associated with treatment timing, suggesting other clinical and individual factors contribute to final prognosis.