A large, cross-sectional British study of almost 7000 children aged 7 to 9 years has confirmed previous findings that visual impairment is rarely the cause of pediatric reading problems. Hence, the still-common practice of vision-based interventions is unlikely to be useful in treating youngsters with severe reading impairment (SRI).

“No indication was found for routinely referring children diagnosed with SRI to an ophthalmologist or optometrist,” write Alexandra L. Creavin, MBChB, an ophthalmologist in the School of Social and Community Medicine, University of Bristol, United Kingdom, and colleagues.

Published online May 25 in Pediatrics, the study, which is the authors say is the first to assess such a broad spectrum of vision abnormalities, found that 4 of 5 children with SRI had normal ophthalmic function in a range of ocular tests. Analyzing data from the Avon Longitudinal Study of Parents and Children (a birth cohort born between 1991 and 1992), the researchers defined reading impairment according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria. Children who achieved more than 2 standard deviations below the mean in the Neale Analysis of Reading Ability Scale II and a level lower than 4 in nonmathematical national key stage 2 tests were defined as having SRI. The researchers excluded children with blindness or IQ lower than 70 from the analysis.

Of 6852 children in the cohort, 225 (3.3%) met criteria for SRI. An additional 624 had moderate reading impairment. Those with reading impairment were predominantly male, with an overrepresentation of low birth weight, preterm birth, and two UK socioeconomic classes: III (mid) and VI (low).

The researchers found no association between SRI and strabismus, motor fusion, sensory fusion at a distance, refractive error, amblyopia, convergence, accommodation, or contrast sensitivity. Stereoacuity worse than 60 seconds/arc was more common in children with SRI than in their peers (1 in 6 vs 1 in 10; P = .001), and there was a nonsignificant trend for increased frequency of abnormalities sensory fusion at near targets (1 in 6 vs 1 in 10; P = .08). “The slight excess of these children among those with SRI may be a result of their reading impairment or may be unrelated,” the authors write.

“The evidence base for currently practiced ophthalmic interventions in SRI is thin, despite their common use,” they conclude. Instead, they recommend that health authorities examine the evidence on managing SRI to optimize outcomes without raising unfounded expectations of vision treatment so that parents can pursue more effective options.

In the absence of national guidelines on ophthalmic interventions in dyslexia management, they add, “The best evidence is for intensive interventions involving instruction on phonics, word analysis, and reading fluency and comprehension.”

The authors have disclosed no relevant financial relationships.

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Pediatrics. Published online May 25, 2015.