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.

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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 2h 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. 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. Reported daily screentimes were 31% <1h, 49.5% 1-2h, 15.6% 2-4h and 3.9% >4h. Reading/writing times were 42.2% frequently, 48.0% infrequently and 9.8% seldom/never. Linear regression, controlling for age and ethnicity, revealed >2h/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 >2h 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 ≤2h/day (OR=3.2, CI: 1.8-5.8, p < 0.001). 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.