Purpose Myopia has been considered a public health issue by the World Health Organization since 2015. The growing incidence of myopia worldwide, called the myopia epidemic, and its potential blinding complications in adulthood like cataract, glaucoma, retinal detachment and maculopathy, have been extensively published and discussed in peer review papers. Nonetheless, little information about Latin America is available. This study aims to detect the prevalence of myopia in southern Brazil, the biggest country of South America.

Methods A prospective cross sectional study recruited 330 public school children between 2019 and 2021, aged 5 to 20 years old. All children underwent a comprehensive eye examination and detailed lifestyle questionnaire. The Pearson correlation coefficient, Kruskal Wallys and the Chi-Square Test were used to assess simple correlations and associations between myopia and medical conditions, use of medications, ophthalmic history and family history of ocular conditions, besides demographics and lifestyle focused on screen time/day. Associations between the results of the ophthalmologic evaluation and all factors included in the questionnaire were analyzed using the Generalized Estimating Equation model (GEE). The prevalence of hyperopia and astigmatism were also assessed.

Results Total prevalence of myopia was 17.4% (CI 13.8 – 21.7%). Low myopia (-0.50D to -5.75D) comprised 15.2% (CI 11.9 – 19.3%) and high myopia (-6,00D or worse) was 2.1% (CI 1.1 – 4.1%). Relative risk of myopia for females was 1.6 (CI 1.00 – 2.57%) and each additional hour of screen time increased a child’s chance of having myopia by 6.5%. The prevalence of hyperopia was 7,7% (CI 5.4 -10.9%) and of astigmatism, either myopic or hyperopic, was 25.6% (CI 21.4 – 30.2%).

Conclusions Brazil has always been considered a hyperopic country. These are the highest reported prevalences of myopia under cycloplegia and the first paper to present myopia as a more prevalent refractive error than hyperopia among Brazilian school children to date.

The authors have declared no competing interest.

The authors received no specific funding for this work

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Hospital de Clínicas de Porto Alegre Ethics Committee approved this study, which adhered to the tenets of the Declaration of Helsinki. Guardians of the children provided written informed consent.

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