Dyslexia and Binocular Vision

Over the past several years, people working across a range of professions have been seeing more and more children who struggle with reading and writing, frequently alongside other difficulties. Teachers notice it. So do psychologists, paediatricians, optometrists, and the therapists who specialize in language and dyslexia. Even ophthalmologists have registered the trend.

When eyes are examined in the usual ophthalmologic way, though, the results tend to be unremarkable. Comparing refractive and orthoptic status between children who read normally and children labeled dyslexic turns up no meaningful gap. The standard check for motor deviation is the cover test, and that test only picks up motor dissociated phorias. Given those findings, the prevailing view within ophthalmology holds that dyslexia has nothing to do with how the visual system works.

A different picture emerges from optometric examination. When you specifically look for associated heterophoria, binocular anomalies turn up in the great majority of dyslexic children, and those anomalies come with sensory adaptations the cover test never catches.

This paper argues something fairly simple. If you take the sensomotor compensations tied to associated phorias (the ones optometric testing brings to light) and correct them to zero, a large share of children with reading and writing difficulties get real relief. Most of the children we saw had been referred to us by school psychologists carrying a diagnosis of dyslexia.

We would rather describe what these children have as dyslexic symptoms. The term dyslexia itself is defined in more than one way, its definition remains contested, and it carries the assumption that the condition cannot be cured. Symptoms, by contrast, are something you can address.

Keywords: reading, writing, dyslexia, latent misalignments, binocular vision.