Reading and Vision


Problems with learning and reading are often cause by vission disorders.


Reading problems are often caused by vision and eye movement problems


If children are struggling with reading they should be taken to see a developmental optometrist who will evaluate the child to determine if the reading problem is in fact a visual problem. Note that some learning problems are cause by bona fide learning disabilities that are not connected to the visual system. The latter likely cannot be treated with vision therapy.


Reading is a prime example of a complex visual task that can be impaired by treatable eye movement disorders, especially binocular vision dysfunctions (in which the eyes do not work together properly). 


Reading requires numerous visual abilities


The simple activity of reading requires an individual to use visual abilities such as distance and near acuity, accommodation (eye focusing), binocularity (eye coordination/eye teaming), ocular-motor skills (eye movement), peripheral vision and visual perceptual skills such as figure-ground, form consistency, spatial relations, visual closure, visual discrimination, visual memory and visualization. A deficiency in any one of these areas will cause a child to fall behind. Fortunately, Vision Therapy has proven effective at treating such deficiencies.


According to pediatrician and member of the parent advisory committee of the National Center for Learning Disabilities, Dr. Debra Walhof M.D.:


It is important to remember that normal sight may not necessarily be synonymous with normal vision...That being said, if there is a vision problem, it could be preventing the best tutoring and learning methods from working. Now that certainly doesn't mean every dyslexic child needs vision therapy, however in my opinion, skills such as focusing, tracking and others are essential foundational tools for reading. In general, if your child has trouble with reading or learning to read, getting a vision evaluation to assess these skills from a qualified Developmental Optometrist would be a smart move.



Vision rehabilitation therapy or psych-ed testing?


Many professionals automatically jump to the conclusion that if a patient has a reading problem, they must be referred for psychological and educational testing. This is because many professionals are not up-to-date on the latest research on vision and reading. If a vision or eye movement problem (i.e. problems with accommodation, convergence, pursuits, saccades, AC/A ratio, etc.) is present, that eye movement problem must be treated first. In other words, it is important to rule out vision as an obstacle to reading. It is appropriate for a struggling reader to be referred for psychological and education testing if no vision problems are present.


Studies have shown that many students labeled "learning disabled" by their school board actually have a treatable vision problem that interferes with their ability to learn. A recent study by researchers at the University of Waterloo in Ontario found that 60% of the students who were labeled disabled by an Ontario school board had binocular vision problems. In the study, records of 68 students ranging in age from 6-12 years were reviewed.  None of them had ever had a previous eye exam.  Children requiring spectacles were not included in the study.  The number of vision problems discovered in this population was astounding:

  • 43% had reduced stereo vision

Six measurements of binocularity were obtained; 60% of patients failed two or more of those tests. If these students had been identified as having a vision problem and treated with vision therapy, they likely would not have continued to struggle in school under the label "learning disabled".Moreover, the failure of many professionals to distinguish between learning disabilities and vision problems may be one of the causes of the over-diagnoses and medication of children for ADD/ADHD.

Recent research has pointed out that children with visual impairments are more than twice as likely as the general population to have a diagnosis of ADHD.




A recent study published in the Journal of AAPOS : The Official Publication of the American Association for Pediatric Ophthalmology and Strabismus/American Association for Pediatric Ophthalmology and Strabismus in February, 2014, found that children with vision disorders are more then twice as likely as the general population to be diagnosed with ADHD. 

The authors of the study looked at a group of visually impaired children between the ages of 4 and 17. The authors found that 22.9% of the kids in this group had a parent-reported diagnosis of ADHD. That was 2.3 times greater than the national average, which is 9.5%.


The fact that a an ADHD diagnosis is twice as common in people with vision problems suggests that may people with vision problems are being misdiagnosed with ADHD. In fact ADHD diagnoses have increased “by 33% between 1997-1999 and 2006-2008.” These statistics are worrisome and suggest a possible over-diagnosis of this condition (see Feldman HM, Reiff MI. Attention Deficit-Hyperactivity Disorder in Children and AdolescentsN Engl J Med. 2014;370:838-846). To learn more about the connection between ADD and vision, click here.


Which professionals are trained to do a vision processing assessment?


Many professionals do not have the education and experience to distinguish between eye movement and vision problems and non-vision based learning disabilities. For example, a study in the journal NeuroRehabilitation recommends that the assessment of visual processing should be done by an optometrist – not an ophthalmologist. The ophthalmologist, according to the authors, does not have the expertise to make the assessment. The study authors note that patients:

should be referred to a behavioral or neuro-optometrist. It was also noted that referrals made to an ophthalmologist may be insufficient, as they are primarily concerned with the health of the eye only, and ophthalmologists are mostly experienced with acute medical problems rather than rehabilitation issues. This assertion is supported by considering the typical components of an ophthalmologic exam, which may yield a lack of specificity, and/or provide information which is inadequately defined in terms of rehabilitation consequence. Trobe, Acosta, Kirscher and Trick identify a lack of measurement in areas of distance and near acuities, contrast sensitivity and confrontation, while Gianutsos and Matheson describe a need for greater quantification in terms of field gradations and boundaries, and binocularity conditions. A more thorough investigation is important for the rehabilitative efforts of all patients who demonstrate visual processing deficits.


The study's authors go on to note that "[o]ophthalmologists are excellent surgeons and expert at treating acute disease but their expertise does not to extend to the diagnosis or treatment of visual processing deficits."


Scientific evidence on reading and vision


A large amount of scientific evidence supports the connection between vision and reading. Many of the relevant studies are discussed below. In addition, the American Academy of Optometry released a position paper on the care of the struggling student in August 2013, which summarizes the latest science in easy to understand language.

While many of these patients who struggle with reading have refractive errors that can be treated with compensatory lenses, some have additional problems in the functioning of the visual system that are best treated by optometric vision therapy.


Most students on individual learning plans have a binocular vision disorder that impacts reading


The evidence on eye problems associated with reading difficulties and learning problems continues to accumulate.  

A recent study entitled Association between reading speed, cycloplegic refractive error, and oculomotor function in reading disabled children versus controls published in the May 2012 issue of the journal Graefes Archives of Clinical Experimental Ophthalmology adds to the evidence of the connection between eye and vision problems and learning.

The researchers were struck by the fact that in Ontario, Canada, approximately one in ten students aged 6 to 16 in Ontario have an individual education plan (IEP) in place because of various learning disabilities.  May of those learning problems were specific to reading.   They wanted to investigate the relationship between reading vision problems and binocular vision problems.

The researchers measured the visual acuity and eye movement measurements of students that had an IEP and compared those results with students in a regular education program.

The researchers found that the IEP group had significantly greater hyperopia, compared to the control group on cycloplegic examination. Vergence facility was significantly correlated to (i) reading speed, (ii) number of eye movements made when reading, and (iii) a standardized symptom scoring system. Vergence facility was also significantly reduced in the IEP group versus controls. Significant differences in several other binocular vision related scores were also found.

Here is the study's conclusion:

This research indicates there are significant associations between reading speed, refractive error, and in particular vergence facility. It appears sensible that students being considered for reading specific IEP status should have a full eye examination (including cycloplegia), in addition to a comprehensive binocular vision evaluation.


Poor readers more likely to have binocular vision deficits


Similar results have been obtained in other studies on vision and reading and the positive impact of vision therapy on those with vision related learning problems. For example, a 2010 study published in the journal BMC Ophthalmology found that children with reading difficulties were more likely to have a wide range of visual problems that are effectively treated with vision therapy, such as poorer distance visual acuity, an binocular vision dysfunctions that are effectively treated with vision therapy such as


  • exophoric deviation at near,
  • a lower amplitude of accommodation,
  • reduced accommodative facility,
  • reduced vergence facility,
  • a reduced near point of convergence,
  • a lower AC/A ratio and
  • a slower reading speed.


The study confirmed the importance of a full assessment of binocular visual status in order to detect and remedy these deficits in order to prevent visual problems continuing to impact upon educational development.


Vision therapy for saccades improves reading fluency


Studies continue to support the positive effect that vision therapy and vision training have on reading. A recent study published in the May 2014 issue of the journal Clinical Pediatrics found that elementary school students who received vision therapy for saccades (saccades are the rapid eye movements from one word to the next that are done when reading) had significantly higher reading fluency scores after treatment, compared with a different group of students that received no therapy. The authors of the study "hypothesize that this improvement in reading fluency is a result of rigorous practice of eye movements and shifting visuospatial attention, which are vital to the act of reading."


To read more about this study on the blog of the College of Optometrists in Vision Development, click here


Reading speed improved by glasses for hyperopia


A study published in the February 2014 issues of the journal Optometry & Vision Science looked at a group of 9- to 10-year old children with hyperopia (farsightedness) and compared their reading ability with and without glasses that corrected the vision problem.


The researchers found that reading scores improved by 13% when the vision problem was corrected.  They also noted that even low amounts of uncorrected hyperopia can negatively influence reading performance. The researchers pointed out the strong association between hyperopia and learning issues problems. According to one review of the study, these learning problems include lower educational test scores, lesser emergent literacy scores, poorer reading progress, underachievement in reading, lower academic test scores, and an association with delays on visuoperceptual, cognitive, motor, and attention tests.


Vision therapy can improve reading comprehension and classroom attention


Results of a study of sixth grade students with below average reading scores found that providing visual attention therapy can significantly improve their attention and reading comprehension.  Visual attention is one component of a group of skills related to visual information processing - the way the brain takes in and makes sense of the images received by the eye.

The developmental optometrists at our Vancouver eye clinic have witnessed this improvement first hand.  Kids who hate reading, can't do it very well and read at below grade level have improved following therapy to become kids who love reading and often can read at above grade level.

The study was published in the November/December 2003 Journal of Learning Disabilities.  The study's authors found that as few as 12 one-hour sessions of vision therapy can enhance reading ability and improve a child's overall attention in the classroom.


Dr. Harold A. Solan, O.D., M.A., FCOVD, Distinguished Service Professor of Optometry at the State College of Optometry, State University of New York and lead researcher for the study gave the following commentary on the results:


Results of this study support previous research that found visual attention and eye movement abilities contribute significantly to a child's ability to read.  This newest research confirms that visual attention can be improved through vision therapy resulting in enhanced reading comprehension.  Far too often, children with reading and learning difficulties may struggle in school because of undetected vision problems.  Difficulties with maintaining visual attention and processing visual information in the classroom doom many children to reading failure. Results of this and other studies now confirm the significance of good visual abilities to reading and learning. Vision abilities needed to succeed in school can be developed through programs of vision therapy which can lead to improvements in reading and learning as found in our study.

Vision therapy programs are tailored by the prescribing doctor depending on the type of visual problem being treated.  To treat visual attention, the therapy included specific procedures to improve perceptual accuracy, visual efficiency and visual search and scanning abilities. Other procedures enhanced how the eyes and brain process visual information. 


The children who were the subjects of the study were tested before and after vision therapy using standardized measures of attention processing.  One group of kids received vision therapy and a second group did not.  The vision therapy group showed significant gains in attention scores and reading comprehension. In terms of learning rate, these students reading skills progressed 1.1 years or 220%.

Visual attention therapy procedures, a part of optometric vision therapy, have for a long time been used in treating patients with learning-related vision problems. According to Dr. Sloan:


This study further confirms the benefits of vision therapy that developmental optometrists have clinically reported in their patients for many years. Vision therapy, a prescribed program of visually guided procedures or 'exercises', is used to help the eyes work together and with the brain to properly interpret visual information.


Visual input is important in developmental dyslexia


An article published in the May 2013 issue of the journal Clinical Ophthalmology confirms that visual input is important in dyslexia and that the focus on language and sound does not fully account for the disorder.

Developmental dyslexia affects almost 10% of school-aged children and is a significant public health issue. It is widely acknowledge that dyslexia involves language and sounds and issues relating to the conversion between written and spoken language. 
However, as the author of the study points out:

Numerous scientific studies have also documented the presence of eye movement anomalies and deficits of perception of low contrast, low spatial frequency, and high frequency temporal visual information in dyslexics. Anomalies of visual attention with short visual attention spans have also been demonstrated in a large number of cases. Spatial orientation is also affected in dyslexics who manifest a preference for spatial attention to the right. This asymmetry may be so pronounced that it leads to a veritable neglect of space on the left side.

This is why eye doctors, especially developmental optometrists (who already have experience and training in treating vision related cognition problems such as visual attention deficits and other visual information processing deficits using eye-brain rehabilitation and vision therapy), need to be involved in providing care for dyslexics.

Vision therapy is the best treatment for convergence insufficiency


Convergence insufficiency is one of the most common vision disorders that interferes with reading. It was recently the focus of a scientific study in the United States funded by the National Institutes of Health and the National Eye Institute - the study found that vision therapy was the most effective treatment for convergence insufficiency. 

Convergence insufficiency is a vision problem where the two eyes don't work together in unison the way they are supposed to when one is reading. The result can make reading very difficult.


This what words on a page look like to someone with convergence insufficiency:

words on a page for someone with convergence insufficiency

It is estimated that least one out of every 20 school-age children is impacted by convergence insufficiency.  


The good news is the majority of these vision problems can be treated with a program of optometric vision therapy. The study by the NEI found that in-office vision therapy was the best treatment for convergence insufficiency.


Vision therapy for convergence insufficiency has been proven effective even in young adults, aged 19-30. In 2005 Scheiman et al. published a clinical trial in Optometry and Vision Scienceon the vision therapy treatment of convergence insufficiency in young adults ages 19-30. Once again, the results proved the efficacy of vision therapy treatment over other modalities that were in use at the time. The study authors concluded:

This first multicenter, randomized clinical trial of the treatment of symptomatic CI in young adults demonstrated that of the three treatment modalities, only vision therapy/orthoptics was effective in achieving normal clinical values for both the near point of convergence and positive fusional vergence. Patients in the pencil pushups group achieved normal values only for positive fusional vergence at near and patients in the placebo vision therapy/orthoptics group did not achieve normal findings for either the near point of convergence or positive fusional vergence at near. Therefore, the effectiveness of vision therapy/orthoptics in improving the near point of convergence and positive fusional convergence values at near in adults cannot be explained on the basis of a placebo effect. Based on the results of this preliminary study, it would appear that pencil pushups, the most popular treatment for CI, is not effective for achieving clinically significant improvements in symptoms or signs associated with CI in young adults.


Vision therapy improves reading and school work performance


In-office optometric vision therapy is the best available treatment for convergence insufficiency.  Convergence insufficiency is a concern for parents, patients and doctors because it causes the eyes to malfunction when doing near work such as reading. And that is a problem because it impacts academic performance.   

We now have a study that confirms that academic behaviours, as measured by the Academic Behavior Survey (ABS), improve following successful treatment of convergence insufficiency.  The study was published in the January 2012 issue of Optometry and Vision Science. The study's conclusion was that "a successful or improved outcome after CI treatment was associated with a reduction in the frequency of adverse academic behaviors and parental concern associated with reading and school work as reported by parents."  


Vision and reading and vision therapy have been the subject of considerable study


According to the College of Optometrists in Vision Development, "the importance of good vision to reading and learning has been the subject of considerable study. Numerous clinical and research studies have shown that good visual abilities are beneficial to learning to read and to read with understanding. Children with normal eyesight (20/20) can have visual problems which affect how their eyes focus, team together, or move along a line of print when reading."


The College of Optometrists has complied a research summary for those interested in learning more about the science behind vision and learning and the positive impact that vision therapy can have on learning and reading, when deficiencies are caused by vision related dysfunctions. Click below to view the research summary:


College of Optometrists in Vision Development Research Summary on<br>
vision, reading and vision therapy: A listing of some of the research reports and clinical studies on the relationship of vision to reading and learning ability and the effectiveness of vision therapy in the treatment of learning-related vision problems.



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