Incidence and risk of attention‐deficit hyperactivity disorder in children with amblyopia: A nationwide cohort study

IMPORTANCE: The association between visual deficits and attention disorders has been reported but remains unproven. BACKGROUND: The objective of this study was to evaluate the risk of attention‐deficit hyperactivity disorder (ADHD) in children with amblyopia. DESIGN: Population‐based, cohort study. PARTICIPANTS: The dataset from the Taiwan National Health Insurance Research Database in 2000 to 2010. METHODS: A total of 6817 patients aged <18 years with newly diagnosed amblyopia were identified. Four age‐ and sex‐matched controls without amblyopia were included for each patient, that is, 27268 controls. MAIN OUTCOME MEASURES: The primary outcome was the risk of ADHD. The secondary outcomes were age at ADHD onset and use of ADHD medication. RESULTS: During a mean observation period of 7.18 years, the incidence of ADHD per 1000 person‐years was 7.02 in the amblyopia group and 4.61 in the control group (P < 0.0001). The ADHD risk in the amblyopia group was 1.81 times that in the control group (hazard ratio 1.81; 95% confidence interval 1.59‐2.06). After stratification by amblyopia subtype, the greatest risk was in the deprivation type (hazard ratio 2.14; 95% confidence interval 1.56‐2.92) followed by the strabismic (hazard ratio 2.09; 95% confidence interval 1.15‐3.79) and refractive (hazard ratio 1.76; 95% confidence interval 1.54‐2.02) types. Age at ADHD onset was younger in the amblyopia group (median 8.14 vs 8.45 years; P = 0.0096). The average duration of neuropsychiatric medication use was comparable between groups (P = 0.98). CONCLUSIONS AND RELEVANCE: The ADHD risk is higher in children with amblyopia.