Purpose: To describe the prevalence of and risk factors for myopia and other refractive errors in a rural, adult, Chinese population.
Design: Population-based, cross-sectional study.
Participants: A clustered, random sampling procedure was used to select 7557 Chinese people aged >or=30 years from Handan, China.
Methods: All eligible subjects were invited to undergo a comprehensive eye examination, including standardized refraction. Myopia, high myopia, and hyperopia were defined as a spherical equivalent (SE) in the right eye of more than -0.5 diopter (D), less than -5.0 D, and 0.5 D or more, respectively. Astigmatism was less than -0.5 D of cylinder. Anisometropia was defined as a difference in SE of >1.0 D between the 2 eyes. Only phakic eyes were analyzed.
Main outcome measures: Myopia and other refractive errors.
Results: We included 6491 (85.9% participation rate) eligible subjects in this study. Adjusted to the 2000 China population census, the prevalence rate of myopia was 26.7% (95% confidence interval [CI], 25.6-27.8), hyperopia 15.9 % (95% CI, 15.0-16.8), astigmatism 24.5% (95% CI, 23.5-25.5), and anisometropia 7.7% (95% CI, 7.0-8.4). The prevalence of high myopia was 1.8% (95% CI, 1.5-2.1). Using a multivariate regression model, current smoking (odds ratio [OR], 0.7, 95% CI, 0.5-0.9), hours of reading (OR, 1.2; 95% CI, 1.1-1.4), diabetes (OR, 8.4; 95% CI, 2.2-32.5), and number of family members with myopia (OR, 1.3; 95% CI, 1.1-1.7, for each family member) were associated with myopia in younger persons (30-49 years). High school or higher education (OR, 1.8; 95% CI, 1.1-3.1), diabetes (OR, 1.6; 95% CI, 1.2-2.7), nuclear opacity (OR, 1.7; 95% CI, 1.2-2.3), and number of family members with myopia (OR, 1.5; 95% CI, 1.2-1.9) were risk factors in persons >or=50 years of age.
Conclusions: Myopia affects more than one quarter of rural Chinese persons >or=30 years of age. Myopia is more common in younger people and is associated with different risk factors than in older people.