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

Abstract

<p><strong>Purpose</strong>: To determine the relationship of attention-deficit hyperactivity disorder (ADHD) with myopia among school children.</p><p><strong>Methods</strong>: 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.</p><p><strong>Results</strong>: 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%; <em>P</em> = 0.02). Multivariable regression analysis showed less myopia (odds ratio [OR] = 0.75; <em>P</em> = 0.03), higher spherical equivalent refraction (SER) (<em>β</em> = 0.13; <em>P</em> = 0.04), and shorter axial length (AL) (<em>β</em> = −0.07; <em>P</em> = 0.03) in children with ADHD. Specifically, ADHD with oral methylphenidate (MPH) treatment had less myopia (OR = 0.61, <em>P</em> = 0.04), higher SER (<em>β</em> = 0.36; <em>P</em> < 0.001) and shorter AL (<em>β</em> = −0.25; <em>P</em> < 0.001) compared to controls. Each additional month of MPH treatment was associated with a higher SER (<em>β</em> = 0.02; <em>P</em> = 0.01) and shorter AL (<em>β</em> = −0.01; <em>P</em> = 0.01). For each one-point increase in attention-deficit scores, children were found to be less myopic (OR = 0.88, <em>P</em> = 0.01), having higher SER (<em>β</em> = 0.07; <em>P</em> = 0.003) and shorter AL (<em>β</em> = −0.04; <em>P</em> = 0.001). The prevalence of myopia among ADHD increased to 32% during COVID-19 pandemic compared with 23% before COVID-19 pandemic (<em>P</em> = 0.04).</p><p><strong>Conclusions</strong>: 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.</p>