VISUAL-ACUITY AND ACCOMMODATION IN INFANTS AND YOUNG-CHILDREN WITH DOWNS-SYNDROME

Accommodation and visual acuity were measured in 53 children with Down 's syndrome aged between 12 weeks and 57 months. Results were compared with data for 136 control (typically developing) children aged betwee n 4 weeks and 48 months. Whereas the control children accommodated acc urately on near targets, accommodation was defective in 92% of the chi ldren with Down's syndrome, and there was no change in accommodative a bility with age. On the other hand, visual acuity lay within normal li mits for the younger children. Children over the age of 2 years showed a below-normal visual acuity, which is not explained either by refrac tive error or by the effect of poor accommodation. The data suggest a sudden change in the rate of development of visual acuity which may be associated with physiological changes in the visual cortex. Previousl y reported defects of accommodation and visual acuity in older childre n and adults with Down's syndrome are confirmed by our findings in inf ants and young children.