We analyzed data on 1,108 patients (1,229 eyes) with various types of retinal vein occlusion. Retinal vein occlusion was classified into six distinct clinical types: (I) nonischemic and (II) ischemic central retinal vein occlusion, (III) nonischemic and (IV) ischemic hemicentral retinal vein occlusion, and (V) major and (VI) macular branch retinal vein occlusion. Retinal vein occlusion occurred more often in men than women. The age range of patients was between 14 and 92 years, with 570 of 1,108 patients (51%) 65 years or older; however, 99 of 620 (16%), 15 of 154 (10%), and 17 of 375 (5%) of the patients with central, hemicentral, and branch retinal vein occlusion, respectively, were younger than 45 years. The cumulative probability of developing a second episode of the same or a different type of retinal vein occlusion in the same eye was 0.9% within two years and 2.5% within four years, and in the fellow eye was 7.7% and 11.9%, respectively. The cumulative probability of conversion of nonischemic to ischemic central retinal vein occlusion at six months and 18 months was 13.2% and 18.6%, respectively, in persons 65 years of age or older and 6.7% and 8.1%, respectively, in persons 45 to 64 years of age.