Iris color and incident cataract and cataract surgery: the Blue Mountains Eye Study.

Abstract

To assess whether an association exists between iris color and the incidence of cataract and cataract surgery. Population-based cohort study. The Blue Mountains Eye Study examined 3654 predominantly Caucasian participants aged 49+ years during 1992-1994, and then 2335 survivors (75.1%) after 5 years. Iris color was determined by comparison with four standard photographs. Slit-lamp and retro-illumination lens photographs were graded for presence and severity of cortical, nuclear, or posterior subcapsular cataract. Incident cataract surgery was recorded by history and from the photographs. Participants with dark brown iris color had an increased incidence of nuclear cataract, odds ratio (OR) 1.8, 95% confidence interval (CI) 1.2 to 2.8, and cataract surgery (OR, 2.5; CI, 1.4-4.2) in multivariate models, compared with participants with blue iris color. Incidence data from this study support previous cross-sectional findings linking dark brown iris color with age-related cataract.