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

Abstract

Purpose: To assess whether an association exists between iris color and the incidence of cataract and cataract surgery.

Design: Population-based cohort study.

Methods: 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.

Results: 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.

Conclusion: Incidence data from this study support previous cross-sectional findings linking dark brown iris color with age-related cataract.