OBJECTIVES:To describe the 15-year incidence of retinal vein occlusion (central retinal vein occlusion and branch retinal vein occlusion) and associated risk factors. METHODS:A population-based study where branch retinal vein occlusion and central retinal vein occlusion were detected at baseline (n = 4068, 1988-1990) and three 5-year follow-up examinations by grading 30 degrees color fundus photographs. RESULTS:The 15-year cumulative incidences of branch retinal vein occlusion and central retinal vein occlusion were 1.8% and 0.5%, respectively. Using a generalized estimating equation model, incident retinal vein occlusion was related to baseline age (odds ratio [OR] per 10 years, 1.70; 95% confidence interval [CI], 1.36-2.12), history of barbiturate use (OR, 5.30; 95% CI, 2.28-12.31), focal retinal arteriolar narrowing (OR, 2.45; 95% CI, 1.29-4.66), glaucoma (OR, 3.17; 95% CI, 1.50-6.69), serum ionized calcium level (OR per 0.4 mg/dL, 0.43; 95% CI, 0.23-0.79), serum phosphorus level (OR per 0.3 mg/dL, 1.15; 95% CI, 1.01-1.30), and serum creatinine level (OR for > or = 1.4 vs < 1.4 mg/dL, 1.61; 95% CI, 1.00-2.59). Migraine headache history was associated with branch retinal vein occlusion (OR, 1.99; 95% CI, 1.08-3.67). Diabetes history was associated with central retinal vein occlusion (OR, 6.35; 95% CI, 1.90-21.27). CONCLUSIONS:Incident retinal vein occlusion is not infrequent in the population, especially after age 65 years. The relationships of barbiturate use, serum creatinine level, serum ionized calcium level, and serum phosphorus level with incident retinal vein occlusion require further assessment in other large population-based studies.