Visual acuity of young men in China: Results from 3 national cross-sectional surveys from 1974 to 2012

Abstract

The prevalence of low vision has increased in China especially among youth population, which is an important public health issue. The trend on the prevalence of subnormal visual acuity and updated information is essential to quantify health effects and to prompt decision makers to prioritize action and assess the effectiveness of measures. Therefore, the study aimed to analyze the prevalence and geographical distribution of visual acuity level among young men in China based on 3 national cross-sectional surveys from 1974 to 2012.The data on visual acuity of young men were collected from 3 national surveys among military recruit youth conducted in 1974, 2001, and 2012 by using a stratified cluster sampling method in China. The prevalence of visual acuity among military recruit youth during this period was analyzed by region, year, age, and economic level.A total of 139,929, 72,894, and 58,106 young men were included, covering all 31 provinces of mainland of China, from the 3 national surveys respectively. The prevalence of subnormal visual acuity had geographic diversity and increased significantly from 1974 to 2012 (P < .05). The visual acuity level was negatively correlated with the age (17-23 years) in 2012 (P < .05). Furthermore, the prevalence of subnormal visual acuity was positively correlated with the gross domestic product in 31 provinces of China (P ≤ .001).The prevalence of subnormal visual acuity increased with economic development among young men from 1974 to 2012, with distinct variation among geographic areas in China. Furthermore, subnormal visual acuity was increasingly prevalent with age and warrant public health attention.

Figure 1

Percentage of young men with visual acuity of both eyes above 1.0 in the 3 national surveys in China.

Figure 2

The visual acuity of young men with age of 17 to 23 years in all, urban, and rural areas in the 2012 survey in China. For each age of year, the median with interquartile range of visual acuity was presented. The Spearman correlation analysis showed significant negative correlation between the visual acuity and age among young men in all areas and in rural areas (P < .001 for both left and right eyes). No statistical difference on visual acuity level was found between urban and rural areas (P > .05 for both left and right eyes).

Figure 3

Relationships between the visual acuity and the GDP in 2012. Correlation coefficients between the visual acuity and the GDP in 2012 (weighted by population average) are r = –0.564 (P = .001) and r = –0.591 (P < .001), for the left and right eyes, respectively. BJ = Beijing, CQ = Chongqing, FJ = Fujian, GD = Guangdong, GDP = gross domestic product, GS = Gansu, GX = Guangxi, GZ = Guizhou, HA = Henan, HB = Hubei, HE = Hebei, HI = Hainan, HL = Heilong-Heilongjiang, HN = Hunan, JL = Jilin, JS = Jiangsu, JX = Jiangxi, LN = Liaoning, NM = Inner Mongolia, NX = Ningxia, QH = Qinghai, SC = Sichuan, SD = Shandong, SH = Shanghai, SN = Shaanxi, SX = Shanxi, TJ = Tianjin, XJ = Xinjiang, XZ = Tibet, YN = Yunnan, ZJ = Zhejiang.