Association of Parental Myopia With Higher Risk of Myopia Among Multiethnic Children Before School Age

Abstract

Importance: Parental myopia is an important risk factor for preschool myopia in Asian children. Further investigation of the association between parental myopia and early-onset myopia risk in other racial/ethnic groups, such as African American and Hispanic white children, could improve understanding of the etiology and treatment of this condition.

Objective: To investigate the association of parental myopia with refractive error and ocular biometry in multiethnic children aged 6 to 72 months.

Design, setting, and participants: This cohort study pooled data from children in 3 population-based studies with comparable design from the US, Singapore, and Australia. Parental myopia was defined as the use of glasses or contact lenses for distance viewing by the child's biological parent(s). Multivariable regressions were conducted to assess the association of parental myopia. Data were collected from 2003 to 2011 and analyzed from 2017 to 2019.

Main outcomes and measures: Cycloplegic refraction and prevalence of myopia (spherical equivalent refractive error of≤-0.5 diopters [D]) in the more myopic eye.

Results: The analysis cohort included 9793 children, including 4003 Asian, 2201 African American, 1998 Hispanic white, and 1591 non-Hispanic white participants (5106 boys [52.1%]; mean [SD] age, 40.0 [18.9] months). Compared with children without parental myopia, the odds ratios for early-onset myopia were 1.42 (95% CI, 1.20-1.68) for children with 1 parent with myopia, 2.70 (95% CI, 2.19-3.33) for children with 2 parents with myopia, and 3.39 (95% CI, 1.99-5.78) for children with 2 parents with childhood-onset myopia. Even among children without myopia, parental myopia was associated with a greater ratio of axial length to corneal curvature radius (regression coefficient for myopia in both parents, 0.023; P < .001) and more myopic refractive error (regression coefficient for myopia in both parents, -0.20 D; P < .001). Effects of parental myopia were observed in all 4 racial/ethnic groups and across age groups except those younger than 1 year. However, parental myopia was not associated with the age-related trends of refractive error (regression coefficient for children without parental myopeia, 0.08; for children with 2 parents with myopia, 0.04; P = .31 for interaction) and ratio of axial length to corneal curvature radius (regression coefficient for children without parental myopeia, 0.031; for children with 2 parents with myopia, 0.032; P = .89 for interaction) beyond infancy.

Conclusions and relevance: Parental myopia, especially childhood-onset parental myopia, was associated with a greater risk of early-onset myopia in Asian, Hispanic, non-Hispanic white, and African American children. The observed associations of parental myopia in children as early as 1 year of age and in children without myopia suggests that genetic susceptibility may play a more important role in early-onset myopia and that parental myopia may contribute to myopia in children by setting up a more myopic baseline before school age.

Figure 1.. Prevalence of Different Levels of Refractive Error by Parental Myopia and Race/Ethnicity

Participants include children aged 36 to 72 months. Error bars indicate 95% CIs. D indicates diopter. ^aP < .05 for difference in the prevalence of myopia (≤−0.5 D) and premyopia (+1.0 to −0.49 D) when comparing children with 1 or 2 parents with myopia with children without a parent with myopia. In multinomial logistic regression adjusted for study, age of the child, sex, educational attainment of primary caregiver, maternal smoking during pregnancy, gestational age, birth weight, maternal age at pregnancy, breastfeeding, and poverty.

Figure 2.. Age-Specific Spherical Equivalent Refractive Error and Ocular Biometry by Parental Myopia Among All Children

Dots represents least squares means and error bars, 95% CI, estimated from multivariable linear regression adjusted for study, sex, educational attainment of the primary caregiver, maternal smoking during pregnancy, gestational age, birth weight, maternal age at pregnancy, breastfeeding, and poverty. ^aP < .05 for children with 1 vs no parent with myopia. ^bP < .05 for children with 2 parents vs no parent with myopia.