Visual function and eye diseases among disabled children – a pilot study

Abstract

Abstract: : Purpose:To estimate the prevalence of children with learning disabilities in a region of Copenhagen County, and to determine the prevalences of visual dysfunctions, low visual acuity (VA), refractive errors (RE) and eye diseases in these children. This study is preceding a survey in the county of Copenhagen. Methods:170 children with learning disabilities were included. The paediatric and ophthalmologic diagnoses and IQ–tests and developmental tests were used as parameters in assessing the level of disabilities. 135 children had an eye examination including VA, RE, strabismic abnomalities, contrast gratings, slitlamp examination and fundoscopy. Results:The prevalence of children with learning disabilities in this region was found to be 1,73 ‰ when borderline cases were included. The children were separated into two groups depending on their level of learning disabilities. Among those with profound learning disabilities (group A, IQ ≤ 70), 39 of 99 children had at least one etiologic diagnose. In the group with less learning disabilities (group B, IQ > 70), etiologic diagnoses were found in 3 of 71 children. We found a correlation between the level of learning disabilities and cerebral palsy (Χ²–test, p=0,001) and epilepsy (Χ²–test, p<0,01). 20 children had VA less than or equal to 0,5 with best possible correction and they were all found in the group A. Fourteen of the 20 children had VA less than or equal to 0,33, and was known in the Danish Register of Visually Impaired. All the children with reduced VA were found in group A (Χ²–test, p<0,0001). 59 % were hypermetropic (> +1D), and 21 % had a significant degree of hypermetropia (more than or equal to +3D) in one or both eyes. 7,4 % were myopic (< –0,5D), 27 % had a degree of astigmatism (> 1cyl D). 27 % had manifest strabismus. The frequency of hypermetropia, myopia, astigmatism and strabismus were all significantly higher in the group A compared to group B. Conclusions:Diagnoses were known for a smaller part of the children. In group A, a higher proportion had an etiologic diagnose, while this was the case only for few of the children in group B. Only a minority of the children in group B was examined by a paediatrician. We found a correlation between learning disabilities, and low visual acuity, cerebral palsy and epilepsy. The proportion of children with low VA in this pilot study is far higher than among Danish children in general. The prevalence of hypermetropia, myopia and strabismus were also found to be considerably higher. The results illustrate the need for further studies in this area.

Keywords: visual acuity • refraction • strabismus