Aim To determine whether there is a significant correlation between the reduction in macular vessel density and the recurrence of macular oedema in eyes with branch retinal vein occlusion (BRVO).

Methods We reviewed the medical records of 27 eyes with macular oedema associated with BRVO. All eyes had received pro re nata intravitreal ranibizumab (IVR) injection. A reinjection of ranibizumab was performed when the central foveal thickness was ≥300 µm. At 12 months, patients without additional IVR for the last 4 months were placed in the resolved group, otherwise they were placed in the recurrence group. The macular vessel density in 3×3 mm area centred on the fovea was determined by optical coherence tomography angiography.

Results At 12 months, 11 of the 27 (40.7%) eyes were placed in the resolved group and the other 16 (59.3%) eyes were placed in the recurrence group. The mean macular vessel density reduction in the resolved group was 17.60%±7.88% and that in the recurrence group was 8.12%±7.48% (P=0.0042). The mean number of IVR injections in the resolved group was 2.1±1.1 and that in the recurrence group was 5.1±1.2 (P<0.0001). In all eyes, multivariate analysis showed that the reduction in macular vessel density was significantly and negatively correlated with the number of IVR injections (β=−0.6746, P=0.0028).

Conclusions A reduction in the macular vessel density was significantly correlated with the number of recurrences of macular oedema associated with BRVO.