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 2000-2010.

METHODS: A total of 6817 patients aged <18 years with newly diagnosed amblyopia were identified. Four age-matched and sex-matched controls without amblyopia were included for each patient, i.e., 27,268 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 versus 8.45 years; P=0.0096). The average duration of neuropsychiatric medication was comparable between groups (P=0.98).

CONCLUSIONS AND RELEVANCE: The ADHD risk is higher in children with amblyopia.