The Association between Early Astigmatism and Myopia Progression in Children

Abstract

Numerous studies investigated the relationship between myopia and astigmatism. Yet, few attempted to answer the important question: ‘ Does astigmatism affect the incidence of myopia and its rate of progression?’. In order to provide further insight into the role of early astigmatism in the development of myopia, this study employed the longitudinal refractive error data of children examined annually between the ages of 7 to 15 years, obtained as part of the Avon Longitudinal Study of Parents and Children (ALSPAC). A comprehensive analytical approach was utilised to understand the determinants and progression of myopia by age 15. The primary outcome variable was ‘myopia at age 15 years’. Logistic regression, linear regression, and survival analysis were used to analyse the various factors influencing the outcome, including spherical power, cylinder power and astigmatism axis measured at different time points (7, 10, 11, and 12 years of age), and a number of confounders such as age, sex, and parental myopia. Missing data were excluded from variables at each age, resulting in logistic regression sample sizes of n = 2404, 2282, 2166, 2126 for ages 7, 10, 11, and 12 respectively, linear regression sample size of n = 2599, 2719, 2585, 2573 for ages 7, 10, 11, and 12 respectively, and survival analysis sample size of 4078. The results showed that, while certain predictors like spherical power and parental myopia emerged as consistently strong predictors, others like cylindrical power and astigmatic axis showed more nuanced influence. The findings highlight the need for a comprehensive, multifactorial approach when assessing myopia risk in children.