Prevalence and Risk Factors of Lens Opacities in Urban and Rural Chinese in Beijing

To determine the prevalence of lens opacities in the elderly Chinese population in an urban and a rural region of Beijing. Population-based cross-sectional study. The study included 4439 subjects of 5324 subjects invited to participate (response rate, 83.4%). The subjects were divided into a rural part (1973 subjects [44.4%]) and an urban part (2466 subjects [55.6%]). The study was limited to participants age 40 and older, and the mean age was 56.2±10.6 years (range, 40–101 years). Nuclear, cortical, and posterior subcapsular lens opacities were assessed based on standardized slit-lamp photographs of the lens using a modification of the grading score of the Age-related Eye Disease Study (AREDS). Grading score of the AREDS. Lens data were provided for 4378 subjects (98.6%) of 4439 persons examined, which consisted of 8724 eyes. Prevalence of any cataract surgery was 1.3% (95% confidence interval [CI]: 1.0–1.7), which was statistically independent of gender ( P = 0.51; odds ratio [OR]: 0.86; 95% CI: 1.00–1.34), rural area versus urban region ( P = 0.25), and level of education ( P = 0.84). Prevalence of any nuclear lens opacity was 82.0% (95% CI: 80.8–83.2); prevalence of any cortical lens opacity was 10.3% (95% CI: 9.4–11.3); and prevalence of any posterior subcapsular opacity was 4.3% (95% CI: 3.7–4.9). If grade 2 of nuclear lens opacity was considered to be normal, prevalence of nuclear cataract was 50.3% (95% CI: 48.8–51.8), and the overall prevalence of any cataract was 53.1% (95% CI: 51.6–54.6), increasing from 6.5% (95% CI: 5.2–7.8) in those subjects 40 to 49 years of age to 52.3% (95% CI: 47.4–55.3) in those who were 50 to 59 years of age, and to 97.8% (95% CI: 96.4–99.2) in those 70 years and older ( P