Epidemiological study of refractive errors in children and adolescents of Han and Li ethnics in the Ledong and Wanning areas of Hainan Province

BACKGROUND: To determine the prevalence of refractive error and ocular biometric data (corneal curvature, axial length, and central corneal thickness) in 6 to 15 years old children of Li and Han ethnicities of China. METHODS: This study was a cross-sectional study. A cluster sampling method was used to select 2 nine-year consistent schools in the Ledong and Wanning areas of Hainan Province, with a total of 4,197 students, 3,969 valid data. Eyesight test, slit lamp, autorefraction after cycloplegia, and ocular biometric assessment were performed. The chi-square test and logistic regression analysis was taken as the comparative method. RESULTS: Myopia, hyperopia, and astigmatism are defined as: myopia: SE ≤−0.50 D; hyperopia: 0.50 D <SE. The absolute value of the cylinder diopter is ≥0.75 D, and the uncorrected visual acuity is lower than the lower limit of the normal age for astigmatism. The prevalence of myopia in the 6–9, 10–12, and 13–15 years old were 3.4%, 16.6%, and 36.4% for the Li, while 11.1%, 32.6 %, and 42.6% for the Han. The prevalence of myopia was significantly different between the three age groups (χ(2)=26.809, 48.045, 4.907, P<0.001, P<0.001, P<0.05). The prevalences of myopia in Li boys and girls were 12.3% and 24.2%, and in the Han boys and girls were 26.1% and 36.6%. The prevalence of myopia was different between boys and girls (χ(2)=60.645, 31.137, P<0.001, P<0.001). In the Wanning and Ledong areas, the prevalences of myopia for the Li were 30.5% and 16.8%, and for the Han were 30.8% and 31.1%. In regard to the prevalence of myopia, no statistical difference was seen in the two nationalities in the Wanning area (χ(2)=0.012, 0.914), but not in the Ledong area (χ(2)=27.305, P<0.001). CONCLUSION: The overall prevalence of myopia in children and adolescents in Han is higher than that in Li The prevalence of myopia in Han and Li was significantly different in different age groups from 6 to 15 years old. The prevalence of myopia in girls was higher than that in boys, in the Wanning area than that in the Ledong area.