The Prevalence of Myopia and Factors Associated with It Among Secondary School Children in Rural Vietnam

Purpose: To assess the prevalence of myopia and associated factors among secondary school children in a rural area of Vietnam. Methods: A school-based cross-sectional study of children in grades six to nine was conducted in four secondary schools in Hoang Mai town, Nghe An Province, Vietnam, during December 2018 and January 2019. The status of myopia was defined as a spherical equivalent objective refractive error of -0.50 D or worse in either eye. A case-control study was conducted to explore factors associated with myopia, where children with myopia were considered to be cases, and children without myopia were considered to be controls. Factors associated with myopia were analyzed using univariate and multivariate logistic regression. Results: The prevalence of myopia among secondary school children was 14.2% (95% CI: 12.7-15.7%) and tended to increase with grade, from 10.5% in grade six to 17.7% in grade nine. Myopia prevalence in girls was significantly higher than in boys. Factors associated with myopia were a mother with a college/university education (OR = 2.5, 95% CI = 1.2-5.3), parents who wore spectacles (OR = 2.0, 95% CI = 1.1-3.8), distance from near work (OR = 5.2, 95% CI = 3.5-7.9), and taking breaks after 30 minutes of continued reading (OR = 1.6, 95% CI = 1.1-2.5). However, there were inverse associations with myopia for children belonging to the wealthiest households (OR = 0.2, 95% CI = 0.1-0.5) and time spent performing outdoor activities (OR = 0.6, 95% CI = 0.4-0.9). Conclusion: Our study showed that the prevalence of myopia is considerable among secondary children in rural areas of Vietnam. The prevalence of myopia tended to increase among children in higher grade levels. Thus, appropriate interventions should be developed and conducted to deal with the issue of school-age myopia.