Correlation between macular vessel density and number of intravitreal anti-VEGF agents for macular edema associated with branch retinal vein occlusion.

We evaluated whether the reduction of macular vessel density was correlated with the number of intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents in eyes with a branch retinal vein occlusion (BRVO). The mean vessel density was determined by optical coherence tomography angiography in 29 eyes with macular edema associated with a BRVO. Our results showed that the mean vessel density in the group that had a resolution of the macular edema after one anti-VEGF injection was significantly higher than group that had a recurrence of the macular edema (P = 0.028). Single regression analysis showed that the number of intravitreal injections was significantly correlated with the reduction of the modified vessel density (r = -0.421, P = 0.023) and systemic hypertension (r = 0.377, P = 0.044). Multiple stepwise regression analysis showed that the reduction of the modified vessel density (β = -0.442, P = 0.009) and hypertension (β = 0.403, P = 0.016) were independent factors associated with the number of intravitreal injections. We conclude that the vessel density reduction can be used to predict whether recurrences of the macular edema will develop after the initial anti-VEGF injection in eyes with macular edema associated with a BRVO.