PURPOSE: To report population data on the association between homocysteinemia and retinal vein occlusion (RVO). DESIGN: Cross-sectional, population-based study. METHODS: Total serum homocysteine (tHcy) was estimated in subjects attending the second Blue Mountains Eye Study (BMES) (n = 3509, aged >49 years). Its association with RVO (graded from retinal photographs) was examined. RESULTS: Homocysteine was more strongly associated with RVO in younger than older participants. In those aged <70 years, homocysteine levels >15 mumol/l were associated with increased odds of RVO, odds ratio (OR) 3.76; 95% confidence interval (CI) 1.06-13.40. in multivariable-adjusted analyses. Each 1 mumol/l increase in homocysteine was associated with a 7% increased odds of RVO, OR 1.07; CI 0.99-1-17 (P = .08). CONCLUSION: This population-based Study showed that elevated serum homocysteine is associated with the presence of RVO, independent of other risk factors. (C) 2005 by Elsevier Inc. All rights reserved.