Refractive Error in Chinese Preschool Children: The Shanghai Study

PURPOSE: To examine the prevalence of refractive error and some associated factors in Chinese preschool children. METHODS: The Jinshan District Eye Study was a school-based survey of eye health in a large sample of 4- to 6-year-olds attending kindergartens from May 2013 to December 2013 in Shanghai. Refractive error was measured using an autorefractor under noncycloplegic conditions. Axial length (AL) was measured with an ocular biometry system. In addition, body height and weight were also recorded. RESULTS: A total of 7,166 children successfully completed their refraction measurements. The median (interquartile range) of spherical equivalent (SE) for all the children was +0.25 D (−0.13 D to +0.62 D), and the range was −15.88 to +18.13 D. The mean AL for all the children was 22.35±0.70 mm, and the range was 18.20 to 27.71 mm. The overall prevalence of myopia (−1.00 D or less), hyperopia (+2.00 D or greater), and astigmatism (1.00 D or greater) were 5.9%, 1.0%, and 12.7%, respectively. After multivariate analysis, more myopic SE (or less hyperopic SE) was significantly associated with girls, longer AL, taller, and lighter. CONCLUSION: Shanghai has a high prevalence of refractive error in the world. However, longitudinal studies are needed to evaluate refractive changes over time in individual children and warranted to prevent the development of myopia.