To prospectively investigate the injection frequency of aflibercept and ranibizumab in the treatment of macular edema in central retinal vein occlusion.Patients with treatment-naive central retinal vein occlusion and macular edema were randomized to receive intravitreal injections with aflibercept (n = 22) or ranibizumab (n = 23) in a treat-and-extend regimen with a follow-up time of 18 months. After 3 loading doses, the treatment intervals were extended by 2 weeks to a maximum of 12 weeks. Intervals were shortened by 2 weeks if macular edema recurred.The number of injections was significantly lower in the aflibercept group with a mean of 10.9 injections (95% confidence interval, 9.6-12.3) compared with 14.4 in the ranibizumab group (95% confidence interval 12.7-16.1) at study completion (P = 0.0017). The mean treatment interval was significantly longer in the aflibercept group compared with the ranibizumab group 10.0 (95% confidence interval, 8.7-11.3) and 6.6 (95% confidence interval, 5.2-8.0) weeks, respectively (P < 0.001). No significant difference between the groups regarding visual acuity or central retinal thickness was observed.Patients with macular edema secondary to central retinal vein occlusion required significantly fewer intravitreal injections of aflibercept compared with ranibizumab when treated with a treat-and-extend regimen. This may reduce the treatment burden and, to some extent, the need for close monitoring of patients.