To compare the effects of early and late intravitreal injection of bevacizumab in patients with macular edema (ME) due to branch retinal vein occlusion (BRVO).

The study sample included 56 eyes of 56 patients who received intravitreal bevacizumab injection for ME due to BRVO and were followed up with at least six months of observation. We retrospectively divided eyes into two classes that included 36 eyes with a disease duration of ≤ 3 months (early treatment group) and 20 eyes with a disease duration of > 3 months (late treatment group). We assessed the effects of injection on the best corrected visual acuity (BCVA), central retinal thickness and IOP at one, three, and six months after treatment.

There was no statistically significant differences in terms of sex, age, number of injections, ischemia, pre-injection visual acuity and central retinal thickness between the two treatment groups. Improvements in central retinal thickness were observed in both groups but were not significantly different between the groups. Visual acuity improved in both groups after treatment; the improvement was significantly better in the early treatment group observed three and six months after treatment. IOP did not change after treatment in either group.

In cases of ME due to BRVO, early intravitreal bevacizumab injection is more effective than late injection for maintaining and improving visual acuity.