Dyslexia and Vision
I have followed a Facebook page of Reading Specialists for several months. So many assessments, theories of reading, instruction frameworks…fascinating and vast…all the while working in underfunded systems. Reading teachers (and all teachers) have tough jobs.
As I do in many FB groups, I occasionally answer questions when symptoms sound like there could be a visual problem influencing reading performance. The response has always been similar.
I am usually met with a link to the American Academy of Pediatrics statement reporting that learning disabilities and dyslexia are not caused by vision problems. While this is true, it also states that “vision is involved in the process of learning”. This 2009 article points to several references concerning dyslexia and the lack of evidence for a visual component in dyslexia.
The article continues that vergence and accommodative problems “can interfere with the physical act of reading but not the processing”. These eye focusing mechanisms allow for a child to see clearly when he is reading up close, but some children have difficulty with this.
Since the publishing of this article, much research has been done.
- Frequency of Visual Deficits in Children With Developmental Dyslexia (2017) which found a high incidence of ocular motor problems in children diagnosed with developmental dyslexia compared to typically developing children. While this does not infer causation, the correlation would suggest that eye movements problems are evident in children with developmental dyslexia at a higher rate than thought. These eye movement problems could be limiting progress with their dyslexia intervention and therefore need to be diagnosed and improved.
- Effect of treatment of symptomatic convergence insufficiency on reading in children: a pilot study (2018) showed improvement in reading comprehension following treatment for convergence insufficiency.
- Current concepts in convergence insufficiency (2018) showed a prevalence of convergence insufficiency of 2-17%, much higher than previously thought.
This research supports that convergence insufficiency (and eye movement disorders) affect reading performance, which occurs at a higher rate for children with dyslexia and at a higher rate than once thought in the typically developing population.
…but the symptoms of vision problems can be mistaken by the public as dyslexia and children with dyslexia often have eye movement problems as well as developmental dyslexia that could be compounding the reading difficulty.
A vision screening can be helpful in finding children with undiagnosed refractive errors. A study of unscreened children ages 10-12 found 75% needing correction (1) making vision screenings a must. While screening is helpful, only a complete eye exam can identify the eye movement problems that may be affecting reading. Still, only 21% of preschool children get screenings and even less get comprehensic=ve eye exams (2).
Vision Therapy does not treat dyslexia…
Convergence problems are easily improved with in-clinic treatment and recommended, even by Ophthalmology (3) .
Support your local eye doctor
Children with reading problems need a comprehensive eye exam to find any problems that may be affecting reading performance. An annual exam is recommended to make sure their vision has not changed.
…and your local teachers
Teachers have a difficult job. I have formed great partnerships with several reading specialists in my area. Thank you, teachers, for helping our kids. This post is dedicated to all of you but especially Marcie, Lauren and Elizabeth, who in the classroom every day.
Want to learn more?
Vision Mechanic.Net has some great videos and articles produced by Dr. Charles Boulet and Robert Constantine, Occupational therapist.
(1)Polling, J.-R., Loudon, S. E., & Klaver, C. C. W. (2012, November). Prevalence of amblyopia and refractive errors in an unscreened population of children. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/23069721.
(2)Castanes, M. S. (2003). Major review: The underutilization of vision screening (for amblyopia, optical anomalies and strabismus) among preschool age children. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/14653775.
(3)Trieu, L. H., & Lavrich, J. B. (2018, September). Current concepts in convergence insufficiency. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/29994854.