A first-of-its-kind study using data acquired from over 11,000 eye tests on children has found no link between eyesight and dyslexia.
Researchers from Bristol and Newcastle universities looked at the results of eye tests in 5,822 participants in Children of the 90s, a large population-based study in the Bristol area. Of these children, three per cent had severe dyslexia and eight per cent had moderate dyslexia. The researchers compared the test results of the children with severe dyslexia with the other 5,650 children of the same age in Children of the 90s who didn’t have dyslexia.
The majority of the dyslexic children were found to have had perfect vision on each of the tests. More than eight in ten (84 per cent) of the dyslexic children fused information from each eye perfectly whilst 16 per cent did not, but importantly said researchers, one in ten (11 per cent) of non-dyslexic children did not fuse either.
The vision tests included moving both eyes and combining information from both eyes and were conducted when the children were aged between seven and nine.
Dr Cathy Williams, a paediatric ophthalmologist and the study’s lead author said the results might allow families to have a better grasp of visual impairments being treated and whether any treatment offered was likely to help their child’s dyslexia.
Dr Alexandra Creavin, one of the co-authors from Bristol University’s School of Social and Community Medicine, added: ‘Our findings may reassure families that their child’s sight is very unlikely to be affecting their reading ability (assuming the need for glasses has been ruled out) and so they can pursue other options for supporting their child.’
Responding to the findings, the British Association of Behavioural Optometrists (BABO) said it was disappointed that the authors of the study felt confident to make such sweeping statements regarding the role of eyesight without fully investigating all areas of the visual processes involved.
‘Behavioural optometry stresses that there is a difference between “eyesight” and “vision,” said BABO chairman John Stevenson.
‘Whilst many children with, and without, dyslexia have 6/6 eyesight, they often struggle to process the information gained by reading into meaningful detail. This study takes two splinter skills of ocular fixation and stereopsis but mentions nothing of visual processing, which is essential for reading.
‘No mention is made of eye movement accuracy, accommodative skills or other aspects of binocularity other than stereopsis. It also makes no mention of the effects of fatigue during reading tasks. Indeed, many of the non-dyslexic group mentioned in the study may have reading difficulties or other learning difficulties which would benefit from optometric involvement.’
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