Visual assessment in Down Syndrome: The relevance of early visual functions

Background: Children with Down Syndrome (DS) have a high prevalence of ocular disorders, and even when ophthalmological deficits (i.e. refractive errors or strabismus) are corrected, visual acuity seems to have a different developmental trend compared to typical children. Unfortunately, there is no consensus about the age at which it is fundamental to perform a first comprehensive visual assessment in this population. Aims: We analyzed early visual functions in a sample of 42 Italian children with DS, in order to achieve new insights for early surveillance and intervention. Material and methods: DS children were evaluated with the Early Neurovisual Assessment, including Teller Acuity Cards (at 6, 12 and 18 months of age) and the Pediatric Ophthalmological Examination (within the 36th months of age). Results: Visual acuity in our sample was lower than findings reported in the literature on healthy Italian children, but the values were within the confidence interval reported in previous studies on DS children. Moderate or severe refractive errors (> 3diopters) were present in five children (four had hyperopia and one myopia). Abnormalities in ocular motility were observed in 15 children and pathological findings for fundus oculi or lens were found in another eight. Furthermore, ophthalmological findings correlated with visual acuity at 18 months of age. Conclusion: According to our results, the Early Neurovisual Assessment at 18 months of life is a reliable tool for early detection of visual disorders in children with DS and it is useful for programming early intervention to promote their neurodevelopment.