Risk factors for anisometropia in schoolchildren: A population‐based, longitudinal cohort study.

Purpose: To investigate the incidence rate and risk factors for anisometropia among young schoolchildren. Methods: A population‐based cohort study, the Myopia Investigation Study in Taipei, was conducted in primary schools in Taipei City. Children were recruited for biannual comprehensive eye examinations over 2 years. Cycloplegic autorefraction and slit lamp examinations were performed biannually. Data on demographic information, parental history, lifestyle and near‐work activities were collected using parent‐administered questionnaires at the first and final visits. Anisometropia was defined as ≥1 D difference in the spherical equivalent (SE) refractive error. Results: A total of 7035 8‐year‐old children completed the 2‐year follow‐up evaluations. The average annual incidence of anisometropia was 3.8%. Multivariable logistic regression analysis revealed that baseline SE (odds ratio [OR]: 0.87 95% CI: 0.80–0.95) and female sex (OR: 1.24, 95% confidence interval [CI]: 1.02–1.50) were significantly associated with incident anisometropia. Among lifestyle risk factors, spending <1 h per day in after‐school outdoor activities on weekdays (OR: 1.38, 95% CI: 1.08–1.76) and performing near work at a distance <30 cm (OR: 1.33, 95% CI: 1.08–1.64) were significantly associated with an increased risk of incident anisometropia. In the multiple linear regression analysis, the inter‐eye difference in SE increased significantly in children performing near work at distances <30 cm (adjusted β = 0.03; p = 0.02). Conclusions: This study indicated the annual incidence of anisometropia in Taiwanese schoolchildren. Less time spent outdoors and shorter eye‐to‐object distances during near work increased the risk of incident anisometropia. [ABSTRACT FROM AUTHOR]