To evaluate the influence of retinal collateral vessels in eyes with macular edema secondary to branch retinal vein occlusion (BRVO) treated with intravitreal bevacizumab (IVB).

We reviewed the medical records of patients with BRVO who were followed up for 12 months. To compare formations of collateral vessels, the patients were divided into 2 groups. The treatment group included 20 patients (20 eyes) treated with IVB, and the control group included 41 patients (41 eyes) without treatment.

In the treatment group, the mean age was 58.4 ± 9.5 years. The average number of IVB injections performed during the 12 months was 4.5 ± 2.5 (range 2 to 8). After 12 months from diagnosis, 13 eyes (65%) presented with collateral vessels. In the control group, the mean age was 60.6 ± 9.3 years and 28 eyes (68.3%) presented with collateral vessel after 12 months. There was no difference in incidence of collateral vessel formation between the treatment group and the control group ( p = 0.574).

IVB does not influence the formation of retinal collateralization in eyes treated for macular edema secondary to BRVO.