Five-year incidence of visual impairment and blindness in adult Chinese the Beijing Eye Study.

Objective: To describe the cumulative 5-year incidence of visual impairment and blindness in adult Chinese in greater Beijing. Methods: Population-based study. Methods: The Beijing Eye Study 2006 included 3251 subjects who had participated in the Beijing Eye Study 2001 and returned for re-examination. Methods: Using the World Health Organization (WHO) definition, low vision and blindness were defined as best corrected visual acutiy (BCVA) <20/60 to 20/400 and as BCVA <20/400 in the better-seeing eye, respectively. Using the United States standard, low vision and blindness were defined as BCVA <20/40 to 20/200 and as BCVA <20/200 in the better-seeing eye, respectively. Methods: Incidence of low vision and blindness. Results: Visual acuity measurements were available for 3249 (99.9%) participants. Using WHO and United States definitions, the incidences of low vision and blindness were 0.5 ± 0.1% (mean ± standard error) and 0.1 ± 0.04%, and 1.1 ± 0.2% and 0.1 ± 0.04%, respectively. In multivariate analysis, incidence of BCVA visual impairment or blindness increased significantly with greater age (P = 0.01), but was not associated with gender, region, or level of education. Causes of BCVA visual impairment or blindness were cataract (39%), glaucoma (17%), and degenerative myopia (11%). Using the WHO and the United States criteria, incidences of low vision and blindness based on presenting visual acuity, were 1.7 ± 0.2% and 0.1 ± 0.06%, and 3.8 ± 0.3% and 0.2 ± 0.08%, respectively. Incidence of visual impairment or blindness (presenting visual acuity, WHO definition) increased significantly with higher age (P < 0.001) and less education (P = 0.018) and was greater in women (P = 0.015). The major cause of presenting VA visual impairment or blindness was undercorrected refractive error (76%). Conclusions: In adult Chinese in greater Beijing, the 5-year cumulative incidence of BCVA visual impairment or blindness was 0.6 ± 0.1% (BCVA in better-seeing eye, <20/60) or 1.7 ± 0.2% (presenting VA in better-seeing eye, <20/60), which increased significantly with age. Measured as presenting VA, this also was associated with female gender and rural region. The major cause (76%) of decreased presenting VA was undercorrected refractive error, followed by cataract. Treating undercorrection of refractive error may be the easiest and most efficient method to improve vision in this community.

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