Amblyopia and Slow Reading

It’s been over a year since I blogged about amblyopia and reading disorders, and the December 2017 issue of the Journal of the American Association for Pediatric Ophthalmology and Strabismus contains commentary on the subject as part of a Symposium on Pediatric Ophthalmology and Childhood Reading Difficulties.

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Insightful observations about amblyopia and slow reading are shared by two Ph.D. researchers, Eileen Birch and Krista Kelly.  Here are some key passages from their commentary:

“Using natural, binocular silent reading of age-appropriate paragraphs of text, we recently reported that children with amblyopia read slowly compared with controls and non-amblyopic strabismic children, regardless of amblyopia type (i.e., strabismic or anisometropic).  Unlike earlier reading studies that focused on strabismus, our study clearly identified that amblyopia alone is sufficient to impair reading. Importantly, comprehension did not differ significantly between amblyopic children and controls, indicating that amblyopic children did not read slowly because they had dyslexia or a learning disability.”

“Unlike dyslexic readers, amblyopic children in our study read more slowly because they made more forward saccades during reading. It is likely that the increased number of forward saccades during reading reflects oculomotor control system deficits. Amblyopia is associated with substantial fixation instability … Taken together, slower saccade initiation, saccade amplitude variability, and increased frequency of secondary saccades can be expected to significantly slow reading speed in amblyopic children.”

“Saccadic eye movements clearly play a key role in efficient reading, a key component of academic achievement. There is a solid evidence base demonstrating slower initiation of saccades and more variable saccade amplitudes in amblyopic individuals. Even though it usually results in poor vision in just one eye, amblyopia can reduce reading speed in natural, binocular reading by 20%-50% and negatively affect academic performance. We have also found that amblyopic children are slower at transferring answers from a standardized test to a Scantron answer sheet compared with visually normal controls. Longer Scantron completion times may exacerbate the problem of slow reading when amblyopic children are administered standardized tests that are time- sensitive, limiting the child’s academic success. The child’s academic achievement, in turn, is a major contributor to the child’s developing self-perception, which has been shown to be affected by amblyopia.  Positive self-perception has an important influence on well-being and quality of life.”

Birch and Kelly conclude:  “While currently there is no evidence that training eye movements will help amblyopic children read faster, parents and educators can work together to implement accommodations (e.g., extra time) to help amblyopic students succeed in their daily school tasks, and improve their performance on the timed, stan- dardized tests that are critical for promotion and admission to magnet schools, TAG programs, high schools, and colleges.”



We could argue over what constitutes “evidence” that training eye movements can enable amblyopic children to read faster (many of our practices are built on such successes), but the take-home message here is that amblyopia is a visual disability that deserves special considerations.  In an invited commentary on Elsevier’s Practice Update for Eyecare, Dr. David Damari, Dean of the Michigan College of Optometry at FSU and a consultant to the National Board of Medical Examiners on Visual Disabilities, noted that the request for accommodations on standardized testing must be documented with performance tests for each individual making such requests.  Which visual performance tests are given weight by testing agencies is an entire subject unto itself.

Screen Shot 2018-02-02 at 11.47.20 AMMuch as CITT-ART is undertaking gold standard research on the transfer effects of training convergence insufficiency to reading, one can anticipate that analogous gold standard research on training amblyopia and its transfer to reading may be undertaken at some point in the future by PEDIG (Pediatric Eye Disease Investigator Group).

9 thoughts on “Amblyopia and Slow Reading

  1. The authors mention faulty saccades. Increased interference from crowding is also characteristic of amblyopia, and may also be a factor. It may impair the ability to subitize which is necessary to start to be able to read whole words (word length effect).
    Gary J. Williams, OD

  2. Interesting post.
    In my opinion, reading is primarily on efferent process, as is amblyopia albeit sometimes in response to afferent factors. Analysis and solution are entirely efferent absent organic anomaly. Anomalous eye movement behavior is a reflection of faulty thinking not faulty equipment in nearly all cases. Poor eye movement profiles are as likely the result of, as the cause of, poor reading. Both must be diagnosed and treated.

  3. You almost take me back to the old Pavlidis/Rayner chicken/egg debates, Steve. Are eye movements contributory to reading difficulties, or a reflection of reading difficulties. Your suggestion that “Anomalous eye movement behavior is a reflection of faulty thinking not faulty equipment in nearly all cases” is interesting. That would not be surprising, given that the eye movements involved in reading are housed in the frontal eye fields, in the seat of thought processes in the frontal lobe.

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