The Influence of Reduced Accommodation on Development of Refractive Error and Binocularity in Children With Down Syndrome

Abstract

Abstract: : Purpose:For the age range 3 months to 12 years about 50% of children with Down syndrome have a significant refractive error (hyperopia ≷=+3.00D, myopia ≷=-1.00D) compared with ∼ 4.5% of control children, and approximately 50% of children with Down syndrome have strabismus, compared with 4-7.5% of control children. In addition, up to 82% of children with Down syndrome show reduced accommodation at near. In order to investigate the influence of accommodation accuracy on the high prevalence of refractive error and strabismus, this study compared the above parameters in children with Down syndrome who accommodated accurately with those who did not. Methods:Children with Down syndrome were seen as part of a longitudinal study begun in 1992. The authors have been involved in continued longitudinal monitoring of the cohort (n = 100). Initial assessment was at the age of 3 to 57 months. Accommodative lag was measured by dynamic retinoscopy. Refractive error was measured using Mohindra retinoscopy and ocular alignment was assessed using cover test, or when this was not possible, Hirschberg test. Only eighteen children from our cohort were found to have accurate accommodation. For analysis, each of these children was age-matched (based on their most recent visit) with a child with reduced accommodation. The most recent visit was used because we have observed that accommodation improves with age in some children. Results:Chi squared analysis of the data from the two groups showed a significantly higher prevalence of convergent strabismus in the under accommodating group (P = 0.008). The distribution of refractive error also differed significantly between the two groups (P = 0.01), with a greater number of hyperopes in the under-accommodating group and a greater number of emmetropes in the accurately-accommodating group. Conclusion:Children with Down syndrome who under-accommodate are more likely to be strabismic and have hyperopia.

Keywords: 623 visual development: infancy and childhood • 397 emmetropization • 304 accommodation