Amblyopia and visual acuity in children with Down's syndrome

Background/aims-Amblyopia in people with Down's syndrome has not been well investigated. This study was designed to determine the prevalence and assoc iated conditions of amblyopia in a group of home reared children with Down' s syndrome. Methods-All children in the study group underwent an evaluation of visual a cuity. In addition, previous ophthalmological records were reviewed, and a subgroup of children was examined. For the purposes of this study, amblyopi a was defined quantitatively as a difference of two Snellen acuity lines be tween eyes or if unilateral central steady maintained (CSM) vision and a cl ear fixation preference was observed. A high refractive error was defined a s a spherical equivalent more than 3 dioptres and astigmatism more than 1.7 5 dioptres. Anisometropia was defined as a difference of at least 1.5 diopt res of sphere and/or 1.0 dioptre of cylinder between eyes. 68 children with Down's syndrome between the ages of 5 and 19 years were enrolled in the fi nal study group. Results-Amblyopia was observed in 15 (22%) of 68 patients. An additional 16 (24%) patients had bilateral vision less than 20/50. Strabismus, high refr active errors, and anisometropia were the conditions most commonly associat ed with decreased vision and amblyopia. Conclusion-This study suggests that the prevalence of amblyopia is higher t han previously reported. Fully 46% of these children with Down's syndrome h ad evidence of substantial visual deficits. These patients may be at higher risk for visual impairment and should be carefully examined for ophthalmol ogical problems.