Seven-Year Incidence of Age-Related Cataracts Among an Elderly Chinese Population in Shihpai, Taiwan: The Shihpai Eye Study

PURPOSE: To report the 7-year incidence of age-related cataracts in a metropolitan Chinese elderly population. METHODS: The Shihpai Eye Study 2006 included 460 (55.8%) of 1361 participants in the 1999 baseline survey for a follow-up eye examination. Cataract was graded by one ophthalmologist using the Lens Opacities Classification System III. RESULTS: The 7-year incidence of pure nuclear opacity was 18.5% (95% confidence interval [CI]: 12.7%-24.3%)]; 34.7% (95% CI: 27.6%-41.8%) for cortical opacity; and 0.6% (95% CI: 0%-1.8%) for posterior subcapsular opacity. On the other hand, 11.6% (95% CI: 6.8%-16.4%) participants developed both nuclear and cortical opacity, 3.5% (95% CI: 0.8%-6.2%) nuclear and posterior subcapsular opacity; and 1.7% (95% CI: 0%-3.6%) cortical and posterior subcapsular opacity. A total of 3.5% (95% CI: 0.8%-6.2%) of participants developed all three types of cataract. Nuclear cataract was significantly associated with current smoking (P = 0.04; relative risk [RR]: 2.05; 95% CI: 1.05-3.99). Males were almost half as likely (P = 0.04; RR: 0.57; 95% CI: 0.34-0.97) to develop cortical opacity, whereas participants with a history of diabetes were approximately twice as likely to develop cortical opacity (P = 0.05; RR 2.43; 95% CI: 1.02-5.81). A higher level of education (P = 0.03; RR: 0.40; 95% CI: 0.18-0.91) and a higher body mass index (P = 0.02; RR: 0.28; 95% CI: 0.10-0.79) was protective of posterior subcapsular cataract. CONCLUSIONS: This study indicated a high incidence of cortical opacities and lower incidence of nuclear opacities compared with Caucasians. Posterior subcapsular opacity incidence and cataract surgery rate were comparable.