(HealthDay)—The incidence of myopia among Chinese students may be as high as 20 to 30 percent each year from first grade onward, according to a study published online July 5 in JAMA Ophthalmology.
Sean K. Wang, from Sun Yat-sen University in Guangzhou, China, and colleagues performed an observational cohort study to examine the incidence of myopia and high myopia based on refraction without cycloplegia among 4,741 children from 19 primary schools and 22 junior high schools.
The researchers found that baseline mean spherical equivalent refraction (SER) was 0.31 diopters (D) among 1,975 students in grade 1 versus −1.6 D among 2,670 students in grade 7. In grade 1 students, the baseline prevalence of myopia was 12 percent, versus 67.4 percent in grade 7 students. Throughout both cohorts, the incidence of myopia was 20 to 30 percent each year. The incidence of high myopia was 0.1 percent in the primary school cohort and 2.3 percent in the junior high school cohort.
"The incidence of myopia among Chinese students based on refraction without cycloplegia is among the highest of any cultural or ethnic group," the authors write.
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