Impact of Area-Level Socioeconomic and Environmental Measures on Reduced Visual Acuity Among Children and Adolescents

PURPOSE. To assess the impacts of area-level socioeconomic and environmental measures on reduced visual acuity (VA).METHODS. This ecological study used the nationally representative cross-sectional data from the Chinese National Survey on Students' Constitution and Health in 2014 (CNSSCH 2014), which included 261,833 participants aged 7 to 22 years randomly selected from 30 mainland provinces in China. Area-level socioeconomic measures assessed included gross domestic product (GDP), population density, density of hospital beds, and nighttime light data measured as the mean digital number (DN) of each region; environmental factors assessed included latitude, annual sunlight duration, and park green space density. The main outcome measure was the prevalence of reduced VA in each province of Mainland China.RESULTS. GDP (coefficient: 0.221; P < 0.001), mean DN (coefficient: 0.461; P < 0.001), latitude (coefficient: 0.093; P < 0.001), and annual sunlight duration (coefficient: 0.112; P < 0.001) were positively associated with the prevalence of reduced VA, while population density (coefficient: -0.256; P < 0.001), park green space per 10,000 people (coefficient: -0.145; P < 0.001), and number of hospital beds per 10,000 people (coefficient: -0.146; P < 0.001) were negatively associated with reduced VA prevalence. Factor analysis indicated a marginally nonsignificant positive correlation between socioeconomic factors and the prevalence of reduced VA (coefficient: 0.034; P = 0.07).CONCLUSIONS. Increased GDP and mean DN, which reflect economic development, were associated with a higher prevalence of reduced VA, while larger park green space and number of hospital beds per 10,000 people seemed to play a protective role, which could be targeted to design preventive strategies for myopia.