Ophthalmic abnormalities and reading impairment

To explore associations between specific learning disorder with impairment in reading (dyslexia) and ophthalmic abnormalities in children aged 7 to 9 years.

Cross-sectional analysis was performed on cohort study data from the Avon Longitudinal Study of Parents and Children. Reading impairment was defined according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Children who achieved >2 SD below the mean in the Neale Analysis of Reading Ability Scale II and level <4 in nonmathematical national key stage 2 tests were defined as having severe reading impairment (SRI). Children with blindness or IQ <70 were excluded.

Data were available for 5822 children, of whom 172 (3%) met the criteria for SRI. No association was found between SRI and strabismus, motor fusion, sensory fusion at a distance, refractive error, amblyopia, convergence, accommodation, or contrast sensitivity. Abnormalities in sensory fusion at near were mildly higher in children with SRI compared with their peers (1 in 6 vs 1 in 10, P = .08), as were children with stereoacuity worse than 60 seconds/arc (1 in 6 vs 1 in 10, P = .001).

Four of every 5 children with SRI had normal ophthalmic function in each test used. A small minority of children displayed minor anomalies in stereoacuity or fusion of near targets. The slight excess of these children among those with SRI may be a result of their reading impairment or may be unrelated. We found no evidence that vision-based treatments would be useful to help children with SRI.