Ametropia prevalence of primary school students in Chinese multi-ethnic regions

Introduction To explore the prevalence of visual impairment due to uncorrected ametropia from primary students in multi-ethnic regions of Yunnan (Southern China).Methods Primary school students of 7 ~ 12 years old from 5 multi-ethnic regions were screened. Cycloplegic refraction and subjective trial lens visual acuity were measured in all children with distance unaided visual acuity < 20/20. Gender, ages, ethnics, and regions were assessed with analysis of difference and Odds Ratio (OR) respectively, by statistics software R.Results Of all 24296 children, the incidence rate for visual impairment from ametropia was 19.18% (myopia accounted for 94.31%) for 7 ~ 12 years old in Yunnan primary schools in a multi-ethnic region. Myopia prevalence differed significantly among gender, ages, ethnics, and regions (P = .0003, P < .00001, P < .00001, P < .00001, respectively). Girls were more prone to have myopia (OR = 1.19, 95%, CI = 1.11–1.27) than boys; the risk of myopia increased with age: 9–10 years OR = 2.6 (95% CI = 2.62–3.2), 11–12 years OR = 6.6 (95% CI = 6–7.26). Three ethnic minorities surveyed were less prone to myopia than Han: Dai OR = 0.62 (95% CI = 0.47–0.8) Hani OR = 0.56 (95%CI = 0.41–0.76) Buyi OR = 0.50 (95% CI = 0.4–0.62).Conclusions Myopia, not corrected by glasses, was the most frequent cause of visual impairment in Yunnan primary schools, in a muli-ethnic region. Boys, young children and certain ethnic minorities were less prone to myopia.