The association between time spent on screens and reading with myopia, premyopia and ocular biometric and anthropometric measures in 6- to 7-year-old schoolchildren in Ireland

Purpose: More time spent on near tasks has consistently been associated with the promotion of myopia. The World Health Organization advises limiting daily screentime to less than 2 h for children aged five and over. This study explored the relationship between time spent on screens and reading/writing with refractive status, ocular biometric and anthropometric factors in 6- to 7-year-olds in Ireland. Methods: Participants were 723 schoolchildren (377 boys [51.8%]), mean age 7.08 (0.45) years. The examination included cycloplegic autorefraction (1% cyclopentolate hydrochloride), ocular biometry (Zeiss IOLMaster), height (cm) and weight (kg). Screentime and reading/writing time were reported by parents/legal guardians by questionnaire. Myopia (≤−0.50D) and premyopia (>−0.50D ≤ 0.75D) risk assessments were performed using logistic regression, and multivariate linear regression was used to analyse continuous variables. Results: Reported daily screentimes were 31% <1 h, 49.5% 1–2 h, 15.6% 2–4 h and 3.9% >4 h. Reading/writing times were 42.2% frequently, 48.0% infrequently and 9.8% seldom/never. Linear regression, controlling for age and ethnicity, revealed >2 h/day on screens was associated with a more myopic spherical equivalent [β = −1.15 (95% confidence intervals {CIs}: 1.62–0.69, p < 0.001)], increased refractive astigmatism (β = 0.29, CI: 0.06–0.51, p = 0.01), shorter corneal radius (β = 0.12, CI: 0.02–0.22, p = 0.02), higher axial length/corneal radius (β = 0.06, CI: 0.03–0.09, p < 0.001), heavier weight (β = 1.60, CI: 0.76–2.45, p < 0.001) and higher body mass index (BMI) (β = 1.10, CI: 0.28–1.12, p < 0.001). Logistic regression, controlling for age and ethnicity, revealed daily screentime >2 h was associated with myopia (OR = 10.9, CI: 4.4–27.2, p = 0.01) and premyopia (OR = 2.4, CI: 1.5–3.7, p < 0.001). Frequent reading/writing was associated with screentime ≤2 h/day (OR = 3.2, CI: 1.8–5.8, p < 0.001). Conclusion: Increased screentime was associated with a more myopic refraction, higher axial length/corneal radius ratio, increased odds of myopia, premyopia, higher degrees of astigmatism, increased weight, BMI and decreased reading/writing time. Dedicated education programmes promoting decreased screentime in children are vital to prevent myopia and support eye and general health.