ObjectiveTo compare the one year efficacy of intravitreal injection with ranibizumb for macular edema (ME) secondary to ischemic and non-ischemic central retinal vein occlusion (CRVO).MethodsA total of 88 patients (88 eyes) with ME secondary to CRVO were enrolled in this retrospective study. The best corrected visual acuity (BCVA) was detected by the Early Treatment Diabetic Retinopathy Study Chart. The optical coherence tomography was used to measure the foveal retinal thickness (CRT) and macular edema volume. The patients were divided into non-ischemic group and ischemic group, 44 eyes of 44 patients in each group. There was no significant differences in age (t=0.650, P=0.517) and gender (χ2=0.436, P=0.509) between the two groups. Compared with the ischemic group, the CRT was significantly decreased in the non-ischemic group (t=−2.291, P=0.024), and the edema volume in the macular area was significantly reduced (t=−2.342, P=0.022). All eyes were treated with continuous intravitreal injection of ranibizumab three times, and repeated injections were performed as needed. The patients without obvious ME regression after treatment were combined with triamcinolone acetonide injection. The patients with peripheral retinal non-perfusion area were combined with peripheral retinal laser photocoagulation. The follow-up was 1 year. The number of injections was counted. The changes of BCVA, CRT and edema volume in the macular area were compared between the two groups.ResultsDuring the 1-year follow-up period, 88 eyes were injected 1 to 10 times, with the mean of 4.51±2.33. The number of injections in the ischemic group and non-ischemic group were 4.55±1.59 and 4.48±2.91, respectively. There was no significant difference in the average number of injections between the two groups (t=0.136, P=0.892). The number of acetonide injections and laser treatment in the ischemic group was significantly higher than that in the non-ischemic group (t=3.729, 9.512; P＜0.001). At the last follow-up, compared with the ischemic group, the BCVA was increased (t=8.128), the CRT was decreased (t=−7.029) and the edema volume in the macular area was decreased (t=−7.213) in the non-ischemic group (P＜0.001).ConclusionCompared with ME secondary to ischemic CRVO, intravitreal injection of ranibizumab for ME secondary to non-ischemic CRVO has the better outcome of vision improvement and edema regression as well as less frequent of acetonide injections and laser treatment.