Purpose. To investigate the development of refractive errors and strabismus in a cohort of children with Down syndrome. method. Data for 55 children with Down syndrome who are participating in this longitudinal study of visual development, first examined by us when aged less than 2 years and on at least two other occasions, were analyzed. Mohindra retinoscopy was used to measure refractive error. Ocular alignment was assessed using the Hirschberg test and, when possible, the cover test. results. Despite the high prevalence of large refractive errors in children with Down syndrome, longitudinal data showed that these are not always present in early infancy. Twenty-one (38%) of the children were emmetropic throughout the study. Of the 24 children with a significant refractive error at the outset, only 6 (25%) showed emmetropization. The others retained or increased their refractive errors. The remaining 10 children were emmetropic at the outset, but then had a significant refractive error develop. There is a high prevalence of strabismus in children with Down syndrome (29% of the total group), which cannot be attributed to the presence of hypermetropia or anisometropia. conclusions. 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.

It is widely recognised that children with Down syndrome have a broad range and a high prevalence of visual deficits and it has been suggested that those with Down syndrome are more likely to exhibit visual perception deficits indicative of cerebral visual impairment. This exploratory study aims to determine the prevalence of behavioural features suggestive of cerebral visual impairment (CVI) occurring with Down syndrome and whether the visual problems can be ascribed to optometric factors. A cohort of 226 families of children with Down syndrome (trisomy 21), aged 4–17, were invited to participate in a validated question inventory, to recognise visual perception issues. The clinical records of the participants were then reviewed retrospectively. A five-question screening instrument was used to indicate suspected CVI. The majority of the 81 families who responded to the questionnaire reported some level of visual perceptual difficulty in their child. Among this cohort, the prevalence of suspected CVI as indicated by the screening questionnaire was 38%. Only ametropia was found to have a significant association with suspected CVI, although this increased the correct prediction of suspected CVI outcome by only a small amount. Results suggest that children with Down syndrome are more likely to experience problems consistent with cerebral visual impairment, and that these may originate from a similar brain dysfunction to that which contributes to high levels of ametropia and failure to emmetropise. It is important that behavioural features of CVI are recognised in children with Down syndrome, further investigations initiated and appropriate management applied.

Background Visual acuity is known to be poorer in children with Down’s syndrome than in age‐matched controls. However, to date, clinicians do not have access to norms for children with Down’s syndrome that allow differential discrimination of healthy from anomalous visual development in this population. Methods The Down’s Syndrome Vision Research Unit at Cardiff University has been monitoring visual development in a large cohort of children since 1992. Cross‐sectional data on binocular visual acuity were retrospectively analysed for 159 children up to 12 years of age in order to establish binocular acuity norms. Longitudinal binocular acuity data were available for nine children who were seen regularly over the 12 years age‐range. Monocular acuity was successfully recorded less often in the cohort, but analysis of scores for 69 children allowed assessment of inter‐ocular acuity differences and binocular summation. Results In comparison with published norms for the various acuity tests used, binocular acuity was consistently poorer in children with Down’s syndrome from the age of three years and stabilised at around 0.25 logMAR from the age of four years. Inter‐ocular acuity difference and binocular summation were both 0.06 logMAR, which is similar to the reported values in children without Down’s syndrome. Conclusions The study provides eye‐care practitioners with the expected values for binocular acuity in children with Down’s syndrome and demonstrates the visual disadvantage that children with Down’s syndrome have when compared with their typically developing peers. The results emphasise the responsibility that practitioners have to notify parents and educators of the relatively poor vision of children with Down’s syndrome, and the need for classroom modifications.