Risk Factors for Strabismus and Amblyopia in Young Singapore Chinese Children

Abstract

Purpose: To determine the risk factors for strabismus and amblyopia in young Singapore Chinese children.Methods: A total of 3009 children were recruited for the population-based cross-sectional Strabismus, Amblyopia and Refractive Error in Singaporean Preschoolers Study (STARS). Strabismus was defined as any tropia identified on cover test. Visual acuity was measured in children aged 30–72 months with a logMAR chart where possible and the Sheridan-Gardiner test if not. Amblyopia was defined based on visual acuity and refractive error or presence of strabismus or past/present visual axis obstruction. Parents completed questionnaires on family, prenatal and birth histories.Results: Our study showed that 24 children aged 6–72 months (1.2%) had strabismus (20 with exotropia), and 20 children aged 30–72 months (0.8%) were amblyopic. After multivariate analysis, strabismus was associated with astigmatism ≥1.00 diopter (D; p = 0.03), amblyopia (p = 0.003), a sibling with strabismus (p < 0.001), and families with lower parental education (p = 0.04). In addition to strabismus, amblyopia was associated with anisometropia ≥1.00 D (p < 0.001) and astigmatism ≥1.00 D (p < 0.001). No association was noted between either strabismus or amblyopia and prematurity, maternal age or smoking.Conclusion: This study highlights the importance of family history in strabismus, and the close associations between refractive error and strabismus with amblyopia. These factors play a more important role in young Singapore Chinese children.