OBJECTIVE The increased cataract prevalence of black populations, especially of cortical cataract, remains unexplained. The authors evaluate the relationships of diabetes, hypertension, and obesity patterns to lens opacities, by age, among 4314 black participants in the Barbados Eye Study. METHODS Prevalence study of a random sample of the Barbados population, ages 40 to 84 years (84% participation). METHODS Associations with age-related lens changes (grade > or = 2 in the Lens Opacities Classification System II at the slit lamp) were evaluated in logistic regression analyses by age (persons < 60 years and > or = 60 years). Results are presented as odds ratios (OR) with 95% confidence intervals. RESULTS Of the 1800 participants with lens changes, most had cortical opacities. Diabetes history (18% prevalence) was related to all lens changes, especially at younger ages (age < 60 years: OR = 2.23 [1.63, 3.04]; age > or = 60 years: OR = 1.63 [1.22, 2.17]). Diabetes also increased the risk of cortical opacities (age < 60 years: OR = 2.30 [1.63, 3.24]; age > or = 60 years: OR = 1.42 [1.03, 1.96]); additional risk factors were high diastolic blood pressure (age < 60 years: OR = 1.49 [1.00, 2.23]) and higher waist/hip ratio (all ages: OR = 1.36 [1.00, 1.84]). Diabetes was also related to posterior subcapsular opacities. Glycated hemoglobin levels were positively associated with cortical and posterior subcapsular opacities. Overall, 14% of the prevalence of lens changes could be attributed to diabetes. CONCLUSIONS The high prevalence of cortical opacities was related to diabetes, hypertension, and abdominal obesity, which also are common in this and other black populations. Interventions to modify these risk factors, especially in populations in which they are highly prevalent, may have implications to control visual loss from cataract, which is the first cause of blindness worldwide.