Association of Attention-Deficit Hyperactivity Disorder With Myopia Among School Children.

Purpose: To determine the relationship of attention-deficit hyperactivity disorder (ADHD) with myopia among school children.

Methods: Children aged six to eight years in Hong Kong were recruited through a stratified, clustered randomized sampling frame and subsequently invited to undergo cycloplegic autorefraction and axial length measurements between 2016 and 2021. ADHD diagnoses were made by qualified physicians according to ICD-10 criteria. ADHD symptoms were assessed using the Strengths and Weaknesses of ADHD-symptoms and Normal-behaviors Questionnaire.

Results: Totally 474 children with ADHD and 9950 control children were included. The age- and sex-adjusted myopia prevalence was lower in ADHD group (21%) versus controls (26%; P = 0.02). Multivariable regression analysis showed less myopia (odds ratio [OR] = 0.75; P = 0.03), higher spherical equivalent refraction (SER) (β = 0.13; P = 0.04), and shorter axial length (AL) (β = -0.07; P = 0.03) in children with ADHD. Specifically, ADHD with oral methylphenidate (MPH) treatment had less myopia (OR = 0.61, P = 0.04), higher SER (β = 0.36; P < 0.001) and shorter AL (β = -0.25; P < 0.001) compared to controls. Each additional month of MPH treatment was associated with a higher SER (β = 0.02; P = 0.01) and shorter AL (β = -0.01; P = 0.01). For each one-point increase in attention-deficit scores, children were found to be less myopic (OR = 0.88, P = 0.01), having higher SER (β = 0.07; P = 0.003) and shorter AL (β = -0.04; P = 0.001). The prevalence of myopia among ADHD increased to 32% during COVID-19 pandemic compared with 23% before COVID-19 pandemic (P = 0.04).

Conclusions: This cross-sectional study found that ADHD is associated with reduced myopia prevalence, more hyperopic SER, and shorter AL. Of note, the observed effect sizes of these associations were small; therefore the interpretation of the clinical meaning needs to be cautious.