Objective: To provide 9-year cumulative incidence of age-related lens opacities in a predominantly black population.
Design: Population-based cohort study, after 9 years of follow-up (n = 2793; 81% participation).
Main outcome measures: Nine-year cumulative incidence and progression of lens opacities, by type, based on the Lens Opacities Classification System II at the slit lamp.
Results: Black participants had a higher 9-year incidence of overall lens changes than white participants (age- and gender-adjusted relative risk [RR], 1.8; 95% confidence interval [CI], 1.2-2.8), as well as of cortical opacities (RR, 3.2; 95% CI, 1.7-6.2). In black participants, incidence rates of any cortical and any nuclear opacities were 33.8% and 42.0%, respectively, and higher than for any posterior subcapsular (PSC) opacities (6.3%). The incidence increased with age for all 3 types, and women had a higher risk of cortical and nuclear opacities (P<0.05). Single cortical opacities were the most frequent type to develop by the 9-year follow-up (23.2%), followed by nuclear-only opacities (17.1%) and mixed opacities (15.3%). Progression rates of pre-existing opacities were 22.0% for cortical, 17.8% for nuclear, and 25.8% for PSC opacities.
Conclusions: The 9-year follow-up of this cohort indicated a high incidence and progression of cortical and nuclear opacities, highlighting the public health importance of cataract in black populations.