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To estimate the prevalence and distribution of blindness and low vision in Northern China.Population-based cohort study.The Beijing Eye Study included 4438 subjects with an age of 40+ years. Mean age was 56.2 +/- 10.6 years (range, 40 to 101 years).Forty-three (1.0%) individuals had low vision (20/60 and/=20/400 best-corrected vision), and 17 (0.4%) individuals were blind (best-corrected visual acuity in the better-seeing eye20/400). Low vision/blindness were significantly associated with age (P.001), myopic refractive error (P.001), and level of educational background (P = .035). It was not associated with gender (P = .76) and rural vs urban area (P = .88).Blindness or low vision affects approximately one in 100 Chinese older than 40 years. An estimated 4.1 million Chinese older than 40 years have low vision, and an estimated 1.6 million Chinese older than 40 years are blind.

Purpose To evaluate intraocular pressure (IOP) and its demographic associations in an urban and rural population in Northern China. Design Population-based cohort study. Methods In the Beijing Eye Study, IOP was measured by noncontact pneumatonometry. Mean age was 56.20 ± 10.59 years (range, 40–101 years). Results Mean IOP was 16.11 ± 3.39 mm Hg (median, 16 mm Hg; range, 7–60 mm Hg). In the rural group and the urban population group, respectively, IOP was significantly ( P = .016 and P = .029, respectively) lower in the high-age group (≥75 years) than in the middle-age group (55–64 years). In the rural group, IOP was additionally significantly lower in the age group of 40 to 44 years than in the middle-age group, which suggests a reversed U-like course. A multiple regression analysis revealed that IOP significantly increased with myopia ( P = .024), and that it was statistically independent of rural area vs urban area ( P = .12) and gender ( P = .71). Conclusion In the Northern Chinese population, mean and median of IOP that is measured by pneumatonometry is 16 mm Hg with a normal range (mean ± two SDs) of 10 to 22 mm Hg. In cross-sectional analysis, IOP slightly increased towards an age of 55 to 64 years and decreased towards higher ages. IOP increased with myopia. It was not associated with rural vs urban region or gender.