Among 407 patients (416 eyes) with retinal vein occlusion (RVO), 196 eyes had branch RVO, 185 eyes central RVO, and 26 eyes hemi-central RVO. The ischemic type accounted for 39.7%, and the non-ischemic type 60.3%. The risk factors were vascular hypertension (59.8%), retinal arteriosclerosis (58.0%), increased blood beta-lipoprotein (49.0%) and fibrinogen (21.7%), and high blood viscosity. The mean levels of whole blood and plasma viscosity were significantly higher in the patients than in the controls. The therapeutic effective rate was 63.2% for branch RVO, 52.4% for central RVO, and 69.2% for hemicentral RVO. The resultant rate of blindness was 15.9%, and that of low vision 23.1%, due to cystoid macular edema (44.4%) and vitreous hemorrhage (15.4%). The incidence of neovascular glaucoma was 9.5% in central RVO.