The retention or development of infantile refractive errors in many children with Down syndrome indicates a failure of emmetropization. All children were at risk of strabismus whatever the refractive error. The findings have implications for timing of screening programs.

Bifocals confer benefit to children with Down's syndrome who under-accommodate, both directly (better focusing through the bifocal) and indirectly (by encouraging improved accommodation through the distance part of the lens). Based on the results of this study, eye examinations of children with Down's syndrome should routinely include a measure of accommodation at near, and bifocal spectacles should be considered for those who show under-accommodation.

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.

Bifocals are an effective correction for the reduced accommodation in children with DS and also act to improve accommodation with a success rate of 65%. Bifocal wear can therefore be temporary, i.e. a 'treatment' for the deficit, in at least one third of children.