Association between accommodative accuracy, hypermetropia, and strabismus in children with Down's syndrome.

PURPOSE: A significant proportion of children with Down's syndrome have been shown to have reduced accommodation. The purpose of this study was to investigate any association between reduced accommodation and refractive error, strabismus, visual acuity, and other ocular parameters.
METHODS: Subjects were children with Down's syndrome enrolled in a longitudinal cohort to monitor visual development. Twenty-seven children with accurate accommodation were age-matched to children with reduced accommodation based on their most recent assessment for which a full, reliable data set was available. Each child was used only once for matching. Cross-sectional ocular and visual data were analyzed using chi or Fisher's exact test, or the Mann-Whitney U test for (non-normally distributed) quantitative data.
RESULTS: Children with under-accommodation were statistically more likely to have moderate/high hypermetropia (> or = +3.00 D) and to be strabismic (most with esotropia). No significant difference between the groups was found for any other ocular parameters.
CONCLUSIONS: This study demonstrates the marked association between under-accommodation, hypermetropia, and strabismus in children with Down's syndrome. No causal relation can be demonstrated with these data, but findings suggest that the link between under-accommodation and hypermetropia (and between accurate accommodation and emmetropia) is present in early infancy.