School-aged children with developmental dyslexia (DD) exhibit more vergence, accommodation and ocular motor tracking deficits than a nonrandomized control group of typically developing (TD) children, new data suggests. Developmental dyslexia is a specific learning disability of neurobiological origin, and the core cognitive deficit is widely believed to involve language (phonological) processing. Still, little is known about the integrity of visual function in individuals with DD.¹

A recent prospective observational study assessed the frequency of visual deficits in 29 children with DD (10 girls and 19 boys) and 33 TD children (21 girls and 12 boys). The differences in frequency between the two groups in vergence deficits, accommodation deficits and impaired ocular tracking were 47%, 46% and 19%, respectively.¹

Overall, researchers saw that 79% of the children in the DD group had deficits in one or more domains of visual function compared with 33% of TD children.¹

While the possible cause and clinical relevance of the deficits are uncertain, the researchers conclude that visual function deficits could contribute to reading acquisition difficulties in children with developmental dyslexia.¹

“While these findings may not be definitive with respect to a ‘causal association of these deficits with reading performance, it would seem that any visual deficit which would impact ‘getting’ to the reading task could very well impair the child’s ability to perform that task optimally,” said Paul B Freeman, OD, in a Practice Update commentary on the study.²