Prevalence of Astigmatism in 4- to 6-Year-Old Population of Mashhad, Iran

Abstract

Background: Astigmatism is a correctable cause of visual impairment in childhood. It increases the incidence of amblyopia in children. Objectives: In this report, we intended to describe the prevalence of the amount and axis of astigmatism, astigmatism components, and associations of astigmatism with age, gender and spherical equivalent in under six years old children through a population-based study. Patients and Methods: This report was a part of the cross-sectional Mashhad Eye Study in which 3675 of 4-6 years old children in Mashhad kindergartens were selected through random cluster sampling, of which, 3701 participated in the study (response rate: 98.3%). Refractive astigmatism was determined using a retinoscope (HEINE BETA-200, Germany) and defined as a cylinder power of more than 0.5 diopter (D). Corneal astigmatism was measured using Pentacam (Oculus Optikgerate GmbH, Germany). Results: The prevalence of refractive astigmatism of more than 0.5D in at least one eye was 51.4% (95% confidence interval (CI): 50.7-52.1); 52.1% in girls and 50.7% in boys (P = 0.412). Prevalence of astigmatism decreased with age, but not statistically significant (odds ratio: 0.97; 95% CI: 0.87-1.07). Mean corneal astigmatism was 1.01 D (95% CI: 0.99-1.03); 1.00 D (95% CI: 0.98-1.02) and 1.02 D (95% CI: 1.00-1.04) in girls and boys, respectively (P = 0.243). Mean corneal astigmatism was not significantly different between different age groups (P = 0.410). Conclusions: The prevalence of astigmatism was high in children under six years old in this study, and to control amblyopia, it is necessary to consider astigmatism at younger ages.