Incidence and progression of lens opacities in the Barbados Eye Studies

Objective: To provide 4-year cumulative incidence and progression rates of age-related lens opacities in a population greater than or equal to 40 year s of age, which is mainly of African origin. Design: Cohort study that reexamined surviving members of the population-ba sed Barbados Eye Study 4 years after baseline. Participants: Three thousand four hundred twenty-seven members of the Barba dos Eye Study cohort (85% of those eligible). Main Outcome Measures: The Lens Opacities Classification System II (LOCS II ) was used at the slit lamp. Cumulative incidence was defined as the develo pment of any nuclear, cortical or posterior subcapsular (PSC) opacities (LO CS II scores greater than or equal to 2) among persons without that opacity type at baseline. Cumulative progression was defined by at least two-step increases in scores among persons with preexisting lens opacities. Results: The incidence of cortical opacities was about five times greater in black than white participants (age-gender adjusted relative risk = 4.7; 95% confi dence interval: 1.9-11.4). In the black population, the 4-year incidence ra tes were 22.2% (20.4%-24.0%) for any cortical, 9.2% (8.2%-10.4%) for any nu clear, and 3.3% (2.7%-4.0%) for any PSC opacities; rates increased greatly with age. Four-year progression rates were 12.5% for cortical, 3.6% for nuc lear, and 23.0% for PSC opacities, without consistent pattern by age. Women had a greater risk of cortical and nuclear opacities (P < 0.05) than men a nd greater progression of nuclear opacities. The presence of PSC opacities at baseline seemed to at least double the incidence and progression rates o f other opacities. In persons initially opacity free, single cortical opaci ties were the predominant type to develop at followup. Visual acuity loss f requently accompanied incident opacities, Conclusions: This longitudinal study provides new population-based data on the natural history of lens opacities. Incidence and progression of opaciti es, especially of cortical opacities, were high. After 4 years of followup, 1 in 4 to 5 participants developed cortical opacities, 1 in 11 developed n uclear opacities, and 1 in 30 developed PSC opacities. The information obta ined attests to the public health impact of age-related cataract, as well a s its extent, in this and similar black populations, (C) 2000 by the Americ an Academy of Ophthalmology.