The effect of age, size of target, and cognitive factors on accommodative responses of children with Down syndrome.

PURPOSE: To investigate possible factors that may be implicated in the poor accommodative responses of individuals with Down syndrome. This article evaluates the effect of age, angular size of target, and cognitive factors on accommodation. METHODS: Seventy-seven children with Down syndrome who are participating in an ongoing study of visual development were assessed. One hundred thirty-one developmentally normal children took part in a previous study and provided control data. Accommodation was measured using a modified Nott dynamic retinoscopy technique. RESULTS: Children with Down syndrome showed considerably poorer accommodative responses than normally developing children. No target used in the present study produced an improved response in children with Down syndrome. Age, angular subtense of target, and cognitive factors could not fully account for the poor accommodation in children with Down syndrome. CONCLUSIONS: Poor accommodation is a common feature of Down syndrome, regardless of the target used. The etiology of the deficit has yet to be established. It is imperative that educators and clinicians are aware that near vision is out of focus for these children.