Pseudomyopia as an independent risk factor for myopia onset: a prospective cohort study among school-aged children

To investigate whether pseudomyopia is an independent risk factor for myopia onset based on a population-based cohort study.Non-myopic children were recruited from schools in rural and urban settings of Shangdong province, China. Baseline examinations started in September 2020 and all participants were invited for a 6-month follow-up. Pseudomyopia was defined as spherical equivalent (SE) ≤-0.50 diopters (D) before cycloplegia and >-0.50D after cycloplegia. Myopia was defined as cycloplegic SE ≤-0.50D.A total of 2328 children (baseline age: 4-17 years) were included in the final analysis. During the 6-month follow-up, 21.1% (355/1680) pseudomyopic eyes developed myopia, and 3.8% (110/2879) non-myopic and non-pseudomyopic eyes developed myopia. After adjusting for multiple myopia risk factors, including baseline cycloplegic SE, near work and outdoor time, pseudomyopia was found to be an independent risk factor for myopia onset (relative risk=2.52, 95% CI 1.86 to 3.42). Additionally, pseudomyopic children with more myopic cycloplegic SE (p<0.001), smaller difference between cycloplegic and non-cycloplegic SE (DIFF, p<0.001), and higher binocular amplitude of accommodation (p<0.001) had higher risk of myopia development.This is an important longitudinal study to prove that pseudomyopia is an independent risk factor for myopia development among school-aged children.