Prevalence of high astigmatism in Salta province, Argentina

Abstract

Purpose: Refractive errors are the first cause of visual impairment across the world. Prevalence data are crucial for planning visual health strategies, since early detection and treatment of refractive errors in children has a key role on normal vision development. This is the largest report in Argentina that has studied refractive errors under cycloplegic refraction in school-aged children.
Methods: Cross-sectional population based study, which involved school children aged 4-15 year-old examined from March to November 2014. Automated cycloplegic refractive error measurement and subjective refraction were performed. Myopia was considered as the spherical equivalent refractive error <-0.50 diopters, hyperopia as > +2.00 D. For the purpose of this study, astigmatism was considered as that equal or greater than -2.00 diopters.
Results: The sample consisted of 1852 children aged 8.03 ± 2.57 years, range 4 to 15 years of whom 967 (52.2%) were females. 116 subjects (6.26%) had a spherical equivalent lower or equal than -0.50 diopters and there were 111 (5.99%) subjects with refractive cylinder ≤ -2.00 diopters (limit -7.50 diopters). In the Seclantas zone (mountainside) the sample comprised 157 children, of whom 20 (12.75%) had astigmatic values in the right eyes ≤ than -2.00 diopters.
Conclusion: An elevated prevalence of high astigmatism and a very low prevalence of myopia were found in this population. Future studies including diverse populations with high prevalence of high astigmatism could contribute to a better understanding of the relevant factors in the etiology of this trait.