[Myopia and Myopic Astigmatism in school-children]

Abstract

Introduction: Worldwide, there is an epidemic increase in myopia. In children, the evidence points to a lack of ex posure to natural light. In Chile, the population situation of myopia in children is unknown. Objec tive: To estimate the tendency of myopia and myopic astigmatism in 1st- and 6th-grade students from the public education system in Chile.

Subjects and method: Ecological study based on diagnostic confirmations of the JUNAEB Medical Services Program, between 2012 and 2018. Annual country prevalence of myopia and astigmatism was estimated by region and sex. The screening evaluation included visual acuity using Snellen Eye Abbreviated chart, red reflex, Hirschberg test, Titmus test, Cover test, ocular motility, and anterior segment examination. Chi2 and logistic regression were used to assess differences and linear regression to estimate average annual change.

Results: Between 2012 and 2018, myopia and myopic astigmatism had a heterogeneous geographical presentation. Myopia and myopic astigmatism ≥ 3 dioptres increased by an annual average of 0.11% (R2 0.67) and 1.21% (R2 0.90), respectively, in 1st-grade children and by 0.2% (R2 0.65) and 8.7% (R2 0.79), respectively, in 6th-grade children. Myopia < 3 dioptres decreased by 0.13% annual average (R2 0.45) in 1st-grade children and myopic astigmatism < 3 dioptres by 0.5% (R2 0.53) in 6th-grade children. High myopic astigmatism affected men more than women and myopia < 3 dioptres affected more 6th-grade females.

Discussion: In schoolchildren of the public education system, myopia and myopic astigmatism > 3 dioptres tend to increase. The protective effect of natural light against myopia has been demonstrated in longitudinal and experimental studies. This evidence is to be considered in promoting children's time spent outdoors.