Vision problems impact reading and learning…a focus for optometry’s next generation of doctors

The research is abundant and the evidence is clear…visual efficiency problems impact reading and learning. In addition to good visual acuity (eye sight), the American Optometric Association (AOA) defines visual efficiency problems as dysfunctions of visual skills involving binocular vision (eye teaming), accommodation (eye focusing) and/or oculomotor (eye tracking) abilities as well as eye hand coordination and visual perception. The AOA defines these visual skills needed for school success. Problems associated with these areas are usually developmental delays or associated with a neurological event, such as a concussion or traumatic brain injury and can be effectively treated with office-based vision therapy.

For over 10 years it has been my honor and privilege, as an Adjunct Clinical Professor at Michigan’s College of Optometry at Ferris State University (MCO),  to present to the 3rd year optometry students on developmental vision and rehabilitation. With the gracious permission of Dr. Mark Swan, Professor of Pediatrics and Developmental Vision at MCO, on October 26, 2018, it was my pleasure to lecture along with my 2 residents, Dr. Jamie Jacobs and Dr. Kelsey Starman in Dr. Swan’s Developmental Vision Course.

Our lecture was entitled: Vision Problems that Impact Reading and Learning. The emphasis in our lecture was to go beyond the academics of these complex issues and  provide a level of appreciation for the important role the doctor has of integrating the science and art of vision therapy/rehabilitation in a private practice to obtain the best outcomes for patients.

Our lecture  involved 3 cases reports of patients treated by the doctors and vision therapists in our practices. Included were the “before” and “after” visual clinical findings as well as reading performance on a variety of standardized reading tests. In addition, each case report included three separate published papers in peer reviewed journals citing the connection between visual efficiency problems and/or the proven results of office-based vision therapy on treating visual efficiency problems involving binocular vision dysfunction, accommodative dysfunction and/or oculomotor dysfunction.

Therefore, in this lecture we presented not just 1 research paper but 9 research papers from around the world that shows the connection between visual efficiency problems and reading/learning problems.

Click here to download a pdf copy of our lecture.Vision problems that impact reading and learning

For addition information, including videos, books, white papers, research and more check out the VisionHelp Vision and Learning Project

Dan L. Fortenbacher, O.D., FCOVD

New Initiative -The VisionHelp Vision and Learning Project collaborative solutions to reading and learning problems

As parents we all want the best for our children and when they struggle to read, learn or grow academically there can be frustration and worry about what to do to find help.

Since vision is the dominant sensory system through which we read, learn and grow academically, vision care professionals need to be involved to identify any problems involving the eyes and vision and remediate and prevent the struggle that occurs when poorly developed vision or a neurological event, such as a concussion, interferes with learning.

However, reading and learning problems can be multifactorial and therefore, when a child is having academic struggles it is important to consider that for many, a professional “team approach,” working together for the common good of the patient, will help ensure the best opportunity for learning. A partnership is developed between the parents and these professionals.

To help parents and professionals, the VisionHelp Group is pleased to announce the release of the latest VisionHelp Initiative, the VisionHelp Vision and Learning Project which provides:

  • Help for parents to learn more about the symptoms and behaviors that may indicate a learning related visual problems…and what can be done
  • Help for professional partners to learn more about well-designed screening protocols and research studies that will help integrate children with learning related visual problems into their clinical practice
  • Help for vision care providers to gain immediate access to the evidence based, best practice protocols for evaluating children and adults to ensure that they are prepared for optimal learning

Dan L. Fortenbacher, O.D., FCOVD

The Olympic games connection to vision-based reading and learning research

What do the Winter Olympic Games have in common with vision-based reading and learning research?

The Winter Olympics brings together the finest athletes from around the globe to compete and show the world how there can be a universal interest in Winter sports and desire to be the best. While you may never have tried to do figure skating or snowboarding the half pipe, when you watch the performance of the these premier athletes in the Winter Games you begin to appreciate the magnitude and complexity of what they are doing, and it touches your mind and heart.

The visual system plays a direct role in the magnitude and complexity of individual performance abilities in every aspect of life. For the Olympic athlete, having good visual efficiency, using both eyes to team, good depth perception, tracking, focus, visual processing and visual motor integration skills are all needed to have peak performance.

But, what about when it comes to the proficiency of a child’s abilities in the day-to-day act of reading and learning? Indeed clarity of sight is important, but there are many visual problems that affects a child’s ability in reading and learning that may not be easily recognizable by just correcting a refractive condition with glasses. For example, vision problems that affect binocular vision (eye teaming) and accommodation (eye focusing) are critical to reading and learning even with 20/20 eye sight. But, some may ask, “Where is the research?”

Awareness for visual efficiency problems, such as Convergence Insufficiency (CI) and its impact on reading and learning, has been reaching the research international stage coming in from around the globe including Canada, India and South Korea, to name a few.

Here are a few examples of the latest in the “Research Olympics” on Vision and Learning:

From India:

Published in the Journal of Optometry, January 2018, entitled: Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies, concluded: “Children with specific learning disorders have a high frequency of binocular vision (BV) disorders and vision therapy plays a significant role in improving the BV parameters.”


From Canada:

Published in the Journal of Optometry, September 2017, entitled: Visual and binocular status in elementary school children with a reading problem, concluded: The results in this study show that children with an IEP for reading also present with abnormal binocular and/or accommodative test results. To thoroughly investigate the binocular vision system, we recommend that tests of accommodation, binocular vision, and oculomotor function should be performed on all children, especially those with identified reading problems.”

From South Korea:

Published in the Journal of Ophthalmic and Vision Research, Volume 12, 2017 entitled: Effectiveness of Vision Therapy in School Children with Symptomatic Convergence Insufficiency, concluded: These findings suggest that vision therapy is very effective to recover from symptomatic convergence insufficiency.”

The United States has been the leader in vision therapy research for vision and learning problems thanks to the tireless efforts by the Convergence Insufficiency Treatment Trial (CITT)“Olympic Team”. Over the last 2 decades the US (CITT) Team has lead this research and published papers that have been voluminous showing that accommodative vergence problems, such as Convergence Insufficiency and Accommodative Disorder can have a major impact on near visual performance such as reading and attention.

From USA:

Published in Archives of Ophthalmology, October 2008 entitled: Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children, the most notable “Gold Medal” US research project by the CITT Team was a multi-center randomized double blind prospective study concluded: “Office-based vergence accommodative therapy is an effective treatment for children with symptomatic convergence insufficiency.”

Additional “Gold Medal” performances by the CITT Team over the last decade has been published in the following papers:

Published in the Journal of Optometry and Vision Science in October 2009: Academic behaviors in children with convergence insufficiency with and without parent-reported ADHD, concluded: “Children with parent report of ADHD or related learning problems may benefit from comprehensive vision evaluation to assess for the presence of convergence insufficiency.”

Published in the Journal of Optometry and Vision Science in January 2012: Improvement in academic behaviors after successful treatment of convergence insufficiency, concluded: “These data suggest that parents may report a reduction in the frequency of specific adverse school and may have less overall worry about academic performance after children with symptomatic CI show improvement or are successfully treated.”

While, like the Olympics, research is complicated and technical, thanks to the dedication of these  “Olympic Research Teams” from around the world, what we know now should touch our minds and our hearts. Vision related reading and learning problems do exist in every country and there is effective treatment with vision therapy.  No longer should children who struggle with reading and learning problems be overlooked from having a binocular/accommodative or other visual problems.The research is clear, but the bigger question is how will we respond to end this senseless struggle for those with vision-based reading and learning problems?

Wouldn’t it only make sense for any child who struggles in reading or learning to have of a comprehensive eye and vision evaluation because, if a visual problem exists, effective vision therapy treatment could be a game changer in that child’s life!

Dan L. Fortenbacher, O.D.,FCOVD


How vision impacts reading, learning and attention through the eyes of an educational specialist

When a child struggles to read it can be very frustrating, not just for the child but for the parents and the teachers.  No parent wants to see their child having trouble with something as important as reading. The same is true for teachers. In many school systems, teachers are now expected to have their students reach certain reading standards and if they don’t, that child may be faced with repeating a grade level.

Meet Wendy Rosen,  a former classroom teacher and educational consultant and author of the new book: The Hidden Link Between Vision and Learning, Why Millions of Learning Disabled Children are MisdiagnosedIn this 6 minute VisionHelp interview, which premiered at the 2017 COVD Annual Meeting, Wendy gives an explanation for why so many children struggle with vision-based learning problems and how to find help they need.

Dan L. Fortenbacher, O.D., FCOVD

A Parent’s reality…Regardless of 20/20 eye sight, remaining vision problems cause reading and learning problems

Dad frustratedLast week I witnessed  the astonished look on a father’s face when his  7 year old little girl (we’ll call Jenny) struggled with some routine chair-side vision tests. His surprise was not during the measurement of her ability to read the eye chart. She read the 20/20 line of letters like a pro. But, when I asked Jenny to visually look at and follow a moving bead on a stick, Jenny responded as if she couldn’t or wouldn’t do it. Observing his daughter’s seeming lack of compliance, Dad began to go into a coaching mode. “Jenny, look at the bead!” , he repeated as I moved it very slowly in front of her face. Then in almost a sense of exasperation he said, “Come on, Jenny, you have to do your best for the doctor”, as if this was a routine personal frustration he had for his 7 year old daughter. Jenny’s face just grimaced as if this was almost a painful process.

So I stopped the visual tracking test and gave Jenny a break. Then I asked her to put on some red/green anaglyph glasses. Sometimes kids call them the 3-D glasses. I asked her to look at a penlight that I positioned about 3 feet in front of her face. Then I brought the light in toward her nose and asked her to tell me when she saw it go double. Jenny reported double at about 14 inches. I repeated the test  2 more times and she consistently reported the light separating into 2 lights further and further away from her face. When her Dad saw this, he thought Jenny was simply “playing around” and said, “Jenny, this is important, you have to try harder!” So, I removed the red/green glasses from Jenny and asked  Dad to put them on. I did the same test on him, except he saw the light remain single up to about 2-3 inches from his nose. Now he was starting to get it!

Girl struggels in readingJenny’s parents situation is not unusual because every family has their own unique side to the story when unaddressed vision problems cause reading and learning problems. It usually begins with a child who is bright and yet struggles in school. In this case their almost 8 yr old daughter, Jenny was  having a difficult time reading. She even had extra tutorial support and attention at school. But, her parents were prepared to retain her in the first grade, even though her teachers said Jenny was capable of “just barely” reading 2nd grade material and suggested that she be promoted to 2nd grade. However, while Jenny could read single words at a time, what she struggled with was reading them in a sentence, losing her place and  slow to do her work. Her parents felt a bit remorseful of having to make a decision to retain her in 1st grade because Jenny was good in math and was mature enough to handle the transition to 2nd grade. But, because of the reading discrepancy Jenny’s parents thought  they should retain her in 1st grade, while on the other hand they were worried that she would get bored and grow to dislike school and feel the emotional sense of failing when her peers were moving forward. They were visibly torn!

Fortunately for Jenny, one of the teachers helping to tutor her, spotted some of the hallmark signs of a visual tracking problem and made the referral to our office. At first, Jenny’s dad was convinced that his daughter couldn’t  have a vision problem because she had passed the school eye sight test and the pediatricians vision screening. But, he and his wife wanted to make sure so they made the appointment.

What did I find? Yes, little Jenny had normal eyes, good eye sight (20/20) and no need for corrective lenses. But, she had severe delays in her Oculomotor (visual tracking)abilities causing her to lose her place when reading, a binocular vision dysfunction (Convergence Insufficiency) causing her to experience intermittent double vision and fatigue when reading and Accommodative (eye focusing) Dysfunction that resulted in loss of visual attention for reading.

I met with Jenny’s parents outlined a treatment plan of twice a week office-based optometric vision therapy and within 4-5 months I expect Jenny will be visually fully functional and able to apply herself in the classroom. Jenny got started last week in treatment, and because we were able to clearly identify a discernible visual problem that can be completely remediated with the proper evidenced-based treatment in a relatively short period of time, Jenny’s parents decided to place her forward into 2nd grade.

If you are like so many who are searching for answers, this story about Jenny helps to give some insight. However, it is probably safe to say that you have questions about how a child, possibly your own child can pass the school or pediatrician vision screening,  reportably have normal sight (20/20) and yet have vision problems that cause significant problems in school, such as reading!? Yes, while Dr. Press and I have written about this extensively on the VisionHelp Blog, sometimes it’s better to hear about it from a parent who has been through it before.

With that thought in mind, here is a video of a mother, Michelle, whose son Dimitre had his crossed-eye surgically aligned, did occlusion therapy and had 20/20 visual acuity, but still had  serious vision problems that blocked his abilities to read, learn, ride his bike and even make friends.  Take a look and see if this helps explain why 20/20 sight is simply not good enough to define vision readiness for reading and learning in the classroom…

For more Facts about vision problems that affect reading and learning, here are some helpful sources:

OSU researchers find conclusive link between vision problems and children with IEPs

Accommodative function in school children with reading difficulties

A summary of research on vision problems associated with reading and learning

To find a doctor nearest you go to and click on the Doctor Locator.

Dan L. Fortenbacher, O.D., FCOVD

Solms on Vision (Beyond Psalm 23)

Among the most famous passages in Psalms (Chapter 23), believed to be authored by King David, comes this verse: “Even as I walk in the valley of the shadow of death, I will fear no evil for You are with me; Your rod and Your staff, they comfort me.” Shadow (visual shading). Rod (visual periphery). Fear (affective distress). Comfort (affective eustress). Might King David be ruminating about elements of visual consciousness?

A new book by prominent South African neuropsychologist Mark Solms does not reference this, but does touch upon the intimate connections between emotion and the senses in particular, and consciousness in general. The basis for its title, The Hidden Spring, is mentioned in a footnote on p. 135: “Unlike other bodily organs, the brain is structurally hierarchical. It is layered somewhat like an archaeological site, with the older levels covered by the newer ones.” The spring in this context is not a mechanical device, but flow as in a body of water; a more genteel version of an Oliver Sacks essay on The River of Consciousness. Coincidence? I think not. Upon reading Sacks’s 1984 book, A Leg to Stand On, Solms entered into a regular correspondence with Oliver, resulting in Sacks writing the foreword to Solms’ The Brain and the Inner World (2002).

The new book of Solms won’t be everyone’s cup of tea, because he is a trained psychoanalyst in addition to being a neuropsychologist. But his affinity for Freud’s influence is shared by other mainstream neuroscientists that he cites, most notably Eric Kandel about whom we’ve blogged before. We tend to forget, though Solms repeatedly reminds us, that Freud began his career rooted in neurophysiology. His early work was conducted in the laboratory of Ernst von Brücke, who had been a research assistant to Johannes Müller. von Brücke made major contributions to physiological optics most notably regarding the actions of the ciliary muscle, and in laying the groundwork for Helmholtz’s invention of the ophthalmoscope. Müller’s name is well-ensconced in the anatomy and physiology of the eye, and taken together they were Freud’s major influences. Freud pioneered in identifying the psychogenic origin of physical anomalies, which ultimately became known as conversion disorders. In the visual system this serves as the foundation for, though is not synonymous with the Streff Syndrome.

Starting at the 10:00 minute mark of the following lecture, Solms sets the foundation for what he discusses at length in his book about the so-called easy problems of consciousness versus the hard problems. In particular, pay attention to “The Knowledge Argument”, beginning at the 12:00 minute mark, and involving a blind neuroscientist named Mary who is suddenly given the gift of sight. While she knows everything there is to know about visual pathways and visual processing, including functional mechanisms, anatomy, and physics, she has never had direct visual experience. She will now learn about the phenomenology of conscious visual experience – what vision actually feels like; what it is like to see the color red; and so forth. (Actually Solms takes some liberties here, because Frank Jackson’s hypothetical story about Mary involves a neuroscientist who acquires a quale of sight – color vision, in particular, rather than sight in its totality. If this sounds familiar, revelation through a quale of vision is what Sue Barry experienced as part of acquiring stereovision.)

On page 185, Solms writes: “Perception proceeds from the inside outwards, always from the viewpoint of the subject. It really is apperception, an inferential process, a matter of Bayesian hypothesis testing. Hermann von Helmholtz, who was the first to grasp the essentials of this, called it ‘unconscious inference’ (again, note the adjective). What you see is your ‘best guess’ as to what is actually out there … Actions should therefore be viewed as experiments that test hypotheses arising from the generative model. If an experiment does not yield the predicted sensory data, then the system either 1) must change its prediction to better explain the data, or, if it remains confident about the original prediction, 2) must obtain better data; that is, it must perform actions that will change its sensory input … the whole point of perception is to guide action.”

On Page 226, Solms states his case for why consciousness isn’t limited to the anatomy of the cortex. Following the processes of perceptual learning and procedural learning, he makes a notable distinction involving memory storage and retrieval. The graphic I’ve extracted below comes from a YouTube lecture in which Solms tosses out the mind-boggling fact that in the course of daily events, only 5% of our processing is conscious in nature. It will highlight the point that Solms makes regarding the critical interplay between cortical and subcortical events.

Solms continues (p. 227): “Non-delcarative memory generates procedural responses, whereas declarative memory generates experienced images. This coincides with an anatomical distinction: declarative memories are cortical while non-declarative ones are subcortical. Subcortical memory traces cannot be retrieved in the form of image for the reason that they do not consist in cortical mappings of the sensory-motor end organs … Subcortical memory traces are more reliable than cortical ones – their high precision values are less likely to change – because they are optimised for simplicity rather than accuracy. This makes them more generalisable. But it comes at a price: the less complex models are less accurate when the context varies. The relative complexity of cortical predictions, on the other hand, coincides with greater plasticity. In a word, the cortex specialises in contexts; it restores model accuracy in unpredictable situations. A trade-off is inevitable. The more potential for conscious experiences, the less automaticity, which means more plasticity but also more cognitive work. That costs energy, and it generates feelings, so the brain does as little of it as it can get away with. Even to the point of fading out a stimulus that is right before your eyes.”

In his postscript on page 301, Solms doubles down on his narrative regarding vision not being an intrinsically conscious function: “The performance of visual functions (even specifically human ones like reading) need not feel like anything. Perception readily occurs without awareness of what is perceived, and learning without awareness of what is learnt … Against this background, it is of utmost importance to observe that cortical functioning is accompanied by consciousness only if it is ‘enabled’ by the reticular activating system of the upper brainstem … The consciousness generated by the upper brainstem has qualitative content of its own. This is affect.”

To that I would add that while visual functions need not feel like anything, they become effortful when the visual system is inefficient. At some level, when our interventions are successful, they imbue perception with affect through the upper brainstem in a way that actions become more pleasurable and meaningful.

How COVID-19 Related Excessive Digital Screen Time Causes Vision Problems in Children

Since the COVID-19 pandemic lockdown measures, there has been a dramatic increase in applications of digital screen time particularly with children in their learning environments. 


For example, in our clinical locations we are regularly hearing from parents of children in elementary school  that their children are on digital devices about 5-8 hours a day.  This translates to 35-40 hours per week or about the same amount of time spent by an adult in a full time job, but in this case it is elementary school children in front of a digital screen. These same children are coming into our clinics because they are experiencing visual-based symptoms. Some are showing increases in distance blur and refraction changes toward progressive myopia (nearsightedness).There is also another, seemingly greater set of children who are not having distance blur, but instead, near vision blur, headaches, eye strain and difficulty with visual efficiency issues involving binocular vision (eye teaming) and accommodation (focusing) and oculomotor (tracking) abilities. There is another smaller group that are manifesting more serious binocular disorders involving an acquired form of esotropia.

Dr. A.M. Skeffington

Those in the field of developmental and rehabilitation optometry recognize the genius of one of developmental optometry’s pioneers, Dr. A.M. Skeffington, who suggested that the “socially compulsive, near-centered visual tasks” common in an educationally oriented  society triggers an autonomic stress response that can be clinically measured. This condition, defined as Nearpoint Visual Stress  has been documented in multiple sources of the optometric literature as a response of the visual system to excessive near point demands resulting in a mismatch between binocular vision and accommodation. While these two components of visual efficiency function, binocular vision and accommodation should work together in harmony, when experiencing Nearpoint Visual Stress the result can be excessive binocular convergence in response to an apparent lag of accommodation (focussing) and vice versa. 

This condition is discussed in excellent detail by another one of developmental optometry’s pioneers, Dr. Martin Birnbaum. In his seminal book entitled, Optometric Management of Nearpoint Vision Disorders, Birnbaum outlines the demands of extended near work, such as reading, requires concentration and attention which sets the stage for an autonomic “fight or flight” response of the visual system. This can lead to the following adaptations to Nearpoint Visual Stress.

  1. Refractive anomalies particularly  Myopia, Nearsightedness
  2. Binocular dysfunction, ex. Convergence Insufficiency and Convergence Excess
  3. Accommodation dysfunction, ex. Accommodative Insufficiency and Accommodative Excess

Additionally, with Nearpoint Visual Stress there typically are behavioral and emotional related conditions triggering anxiety, reduced self esteem and even depression. Another common behavior side-effect is a significantly reduced attention and concentration for reading related activities. 

Moving this now into the year 2020, the COVID pandemic has rapidly  accelerated Nearpoint Visual Stress by societally imposed excessive digital screen time. This has accelerated these visual conditions to an even greater concern than ever before. One example of this was published in the American Journal of Ophthalmology July 29, 2020 entitled: Digital Screen Time During COVID-19 Pandemic: Risk for a Further Myopia Boom.

Another example was published in the Journal of Pediatric Ophthalmology and Strabismus August 2020 entitled: Acute Acquired Concomitant Esotropia from Excessive Application of Near Vision During the COVID-19 Lockdown.

What can be done? 

First, it’s important to realize that there are many educational benefits to having access to digital technology for enhanced learning opportunities. These new virtual learning  platforms have expanded access to information and methods to stay connected as well as a plethora of knowledge-based resources. At the same time, if unaddressed, there can be a host of visual consequences.

Therefore, to help offset the  impact of Nearpoint Visual Stress, an important common sense approach is to recommend “visual stress relief” from digital devices as part of the Nearpoint Visual Stress management strategy. One such example is applying the 20/20/20 rule for visual breaks every 20 minutes by looking 20 feet away (or more) for 20 seconds.

Furthermore, it is important for parents to have their children with signs and symptoms of Nearpoint Visual Stress to have a Comprehensive Eye Health and Vision Evaluation. For those children who are progressing in nearsightedness, or showing sensorimotor dysfunctions, such as convergence insufficiency or  excess and accommodative insufficiency or excess, should be seen by a Developmental Vision/Rehabilitation Optometrist. The application of nearpoint stress relieving lenses, often with “blue blocking” filters can be a critically important preventative tool for Nearpoint Visual Stress. When visual conditions that involve binocular and accommodative dysfunction go beyond what can be managed with lenses alone OR the patient has more extreme forms of binocular vision failure such as acquired esotropia, a consult for office-based vision therapy should be prescribed as an  important management of Nearpoint Visual Stress. 

In this era of excessive application of digital screen time we need a more collaborative approach, ophthalmology, primary care and developmental/rehabilitative optometry; working together to find solutions, to end the senseless struggle that affects so many children from induced Nearpoint Visual Stress. 

Dan L. Fortenbacher, O.D., FCOVD

Oops! Page Not Found … Interview with Debbie Walhof, M.D. on Vision & Learning

In 2013, along with the pediatrician Dr. Debra Walhof, I co-authored an article titled: Could Vision Issues Be Contributing to Your Child’s Difficulty With Learning?  At the time Dr. Walhof was a parent advocate with the National Center for Learning Disabilities or NCLD.  But if you search for that paper now, all you’ll come up with is:

Screen Shot 2020-07-29 at 11.15.40 AM

However, I was pleased to discover that the article is still accessible as a PDF through the website  But in case that site succumbs to the infamous 404 OOPS, and the article can no longer be found, I am reproducing it here in its entirety.

Screen Shot 2020-07-29 at 11.36.04 AM

Screen Shot 2020-07-29 at 11.33.46 AM



Parents and educators often ask us questions about vision therapy and if it can be helpful for children with LD. While vision problems are not the cause of dyslexia or other learning disabilities, vision issues such as convergence insufficiency can certainly interfere with learning and contribute to difficulties with attention and behavior. And some practitioners report that convergence insufficiency may be more common in individuals with LD and ADHD.

We turned to a pediatrician, Debbie Walhof, MD, and an optometrist, Leonard Press, OD, to answer questions about vision therapy, convergence insufficiency, and what parents should know if they are considering vision therapy for their child.


What is Convergence Insufficiency (CI)? Is it related to dyslexia?

Our eyes are designed to work together to give us single, clear vision. Convergence Insufficiency (CI) is an eye coordination disorder, where the two eyes do not work together the way they are supposed to. As with any disorder, you can have a mild to severe case. The more severe the disorder, the more difficult it is for the eyes to work in ways that support effective reading. Some of the more common symptoms of CI are similar to those symptoms described by individuals with dyslexia or another reading disability when they describe what they “see” while reading, so it could be easy to confuse the two.

For example, CI can cause double vision or “ghosting” of print. Since children do not know how they are supposed to see, they rarely complain when they see double. Instead they struggle with reading, often avoiding it at every opportunity. They may be able to read aloud in a very broken, non-fluid manner, yet they don’t remember what they read.

Does CI occur more frequently in those with dyslexia than in the general population? What about in individuals who have ADHD and other disorders that impact learning, attention and behavior?

CI is estimated to occur at least three times more frequently in children diagnosed with ADHD as compared to the general population. Recent studies have established a link between CI and dyslexia, particularly regarding the negative impact of CI on the type of eye movements used when reading, called “saccades” in the professional literature.

Can CI be treated? Will curing CI cure (or help treat features of) dyslexia?

According to research funded by the National Eye Institute, part of the National Institutes of Health, not only is it possible to treat CI, but the treatment of choice is in-office optometric vision therapy combined with home reinforcement activities. While vision therapy is an optometric specialty service, the research was conducted as a multicenter study involving ophthalmologists and optometrists in a variety of academic settings across the United States.

First, it is important to understand that optometric vision therapy treats vision problems, not learning disorders. Having said that, when a vision disorder is at the root of a child’s difficulties with reading, we often see children excel once the vision problem is corrected. For children who have severe learning difficulties, vision therapy resolves the visual component to their challenges. Tutoring and other services often become more successful once the vision problem has been treated.

I’ve heard people say that vision therapy is a waste of time. Why would they say that, and what should I believe?

There are a variety of possible reasons why someone would say vision therapy is a waste of time. Typically it is because they are not up to date on the scientific literature supporting vision therapy. Or perhaps they know of a child who was engaged in vision therapy for many months and for whom there seemed to be little or no apparent benefit in terms of improved performance in school. Here are some important rules of thumb:

Vision therapy provides a highly specialized type of treatment for a very specific set of vision-related problems. Not every child is a candidate, and vision therapy alone may not result in better school success.

As with any therapeutic intervention, it must be implemented with fidelity. Professionals must use the right strategies over the proper period of time with clear goals and ongoing monitoring of progress, with adjustments made as needed.

Effective treatment for CI is clearly dependent not only on office-based treatment with a trained provider but also on the child’s commitment to regularly doing exercises at home.

If possible symptoms of CI emerge during my child’s pediatric office visit, what should the pediatrician do?

The best thing your child’s pediatrician can do is review the symptom checklist that was used in CI studies funded by the National Eye Institute. If your child has many of these symptoms, it indicates that your child probably has an eye coordination problem and needs to have a binocular vision evaluation by a developmental optometrist or an optometrist who provides an in-office vision therapy program. Although optometrists and ophthalmologists can diagnose CI, you may want to choose a developmental optometrist for diagnosis who is also skilled in the therapeutic treatment for CI through vision therapy.


These studies found that children with CI reported that the following symptoms occurred “fairly often” or “always” while reading or doing close work:

Screen Shot 2020-07-29 at 11.42.11 AM

Other than “pencil push-ups,” what are some strategies used to treat CI?


“Pencil Push-ups” is an activity where a person holds a pencil at arms length in front of his or her face and keeps their eyes fixed on the tip as it is moved closer and closer to the face. Despite popularity of this activity, the study funded by the National Eye Institute found that doing “pencil push-ups” was no more effective than placebo therapy.

When working with children it is important that activities are designed to be engaging while teaching them how to use their eyes correctly. For example, tossing a bean bag back and forth might initially appear very simple, but if you put special lenses on the child to help the two eyes work together correctly, this simple game now becomes a therapeutic activity. There are also some very sophisticated computer programs specifically designed to be used with therapeutic lenses.

In addition, some parents are concerned as to whether or not their child can actually do what is needed to get through the therapy program. The activities are individualized for each child’s abilities. They start out very simple and become more demanding as the visual skills improve.

More clinically speaking, the procedures used in the landmark CI study included activities to help the eyes focus accurately through a variety of lens powers, and to team (work together) more accurately. Better integration of tracking, focusing, and eye teaming can be accomplished with something as simple as a Brock String (a 10 foot chord with three beads on it), or as complex as interactive computer activities with special binocular glasses. The optometrist selects the strategies best suited to the individual child.

Who does the treatment, and how long does it take?

While some doctors will provide vision therapy sessions personally and directly with their patients, many optometrists have vision therapists working with their patients under supervision of the doctor. The length of treatment can be as short as three to six months in uncomplicated cases, to much longer when other problems coexist with CI such as Cerebral Palsy or Traumatic Brain Injury.Make sure you understand the exact nature of your child’s vision problem.Ask the doctor how much continuing education they have attended and continue to attend on vision therapy. You want your child to see someone who is up to date on the latest research and technology.


Ask to see the vision therapy room. While a tremendous amount of equipment is not needed to treat CI, ask to be present during your child’s first therapy session to gain a sense of how treatment is conducted. If, after two- months, you do not see any incremental improvement despite attending weekly and getting home therapy done as instructed, you should reevaluate whether this is an appropriate therapy for your child and discuss this with the doctor.

Ask the doctor to download and share the Fact Sheets from the College of Optometrists in Vision Development that correspond to your child’s specific diagnosis. (They can be accessed through the member’s only section of the website). These Fact Sheets explain the appropriate length of treatment.

Getting a second opinion is always beneficial, as long as you see a doctor who also provides an in-office program of optometric vision therapy. Ideally the doctor would also be a Fellow of the College of Optometrists in Vision Development, and therefore board certified in this field.


How can I find the right professional to treat CI? Will most Optometrists know what to do?

While all optometrists learn about vision therapy in optometry school, you want to find an optometrist who provides an in-office program of vision therapy. Most optometrists know how to diagnose CI, but it is important that you let them know the symptoms your child is reporting or the signs you are observing. If your child’s eye doctor says “everything is fine” yet your child continues to struggle with reading despite all best efforts to help, find your closest doctor certified in vision therapy at and schedule an appointment.

As with any profession, you will find some practitioners who are more knowledgeable than others. Therefore it is vital that you ask how much experience the doctor has had with patients similar to your child. You can also ask to speak with some parents of children who have also had CI and reading difficulties, who went through their vision therapy program.

Vision therapy is expensive, and maybe not be (fully) covered by insurance. How can I decide which treatment approach is going to be both affordable and effective?

If your child has an eye coordination problem such as CI contributing to his or her challenges with reading, then it is important to fix the vision problem first. Over the years the majority of patients I have helped struggled for years trying all other treatment options before finding out their children had vision problems that were easily corrected.

Many of my patients have shared that they spent thousands, if not tens of thousands, trying to help their children with forms of treatment that proved inadequate prior to consulting me about optometric vision therapy.

To determine which treatment approach will be both affordable and effective, you can:

Make sure you understand the exact nature of your child’s vision problem.

Ask the doctor how much continuing education they have attended and continue to attend on vision therapy. You want your child to see someone who is up to date on the latest research and technology.

Ask to see the vision therapy room. While a tremendous amount of equipment is not needed to treat CI, ask to be present during your child’s first therapy session to gain a sense of how treatment is conducted. If, after two- months, you do not see any incremental improvement despite attending weekly and getting home therapy done as instructed, you should reevaluate whether this is an appropriate therapy for your child and discuss this with the doctor.

Ask the doctor to download and share the Fact Sheets from the College of Optometrists in Vision Development that correspond to your child’s specific diagnosis. (They can be accessed through the member’s only section of the website). These Fact Sheets explain the appropriate length of treatment.

Getting a second opinion is always beneficial, as long as you see a doctor who also provides an in-office program of optometric vision therapy. Ideally the doctor would also be a Fellow of the College of Optometrists in Vision Development, and therefore board certified in this field.


Why do some doctors say vision therapy is controversial or that it lacks research?

Even though there is a wealth of optometric research which proves that vision therapy works, there are some in the medical (ophthalmology and pediatric) community who have the misimpression that there is insufficient evidence. The fact is that vision therapy is an optometric specialty and therefore the bulk of the research is in the optometric journals, not the medical journals. Vision therapy is not new; it has been around for 85 years!

In Summary

The bottom line is that NIH studies demonstrated that vision therapy is a valid treatment for CI. We know that many children, including those with learning disabilities, have CI so screening for CI in this population makes sense.

Healthy eyes and proper vision are essential ingredients for effective learning; reading, writing, spelling and math are all areas that could be affected by uncorrected problems with vision.

If your child is having trouble seeing, reading or writing, think about CI as a possible factor.

Parents should seek needed services from qualified professionals to discover and treat problems related to vision. The most qualified professionals to whom you should turn for expert guidance, evaluation or treatment are developmental optometrists who have completed fellowship training in this area.

Parents should be sure to include school personnel in their efforts to provide needed treatment and support for their children (for example, by identifying ways to support therapeutic progress during school activities) and should be sure that children are receiving the best quality academic instruction (in reading and in other areas) to maximize their opportunities for success.

If treatment is begun and no discernible improvement is seen within a few months despite doing everything as instructed, ask your child’s primary care physician to consult with the developmental optometrist.

For more information about healthy vision and dyslexia, see this informational sheet from the College of Optometrists in Vision Development: _vision_and_dyslexia.pdf?hhSearchTerms=dyslexia

Debbie Walhof, MD is an Associate Clinical Professor at the University of California San Francisco and a practicing pediatrician with specialty training in the area of integrative medicine. She is also a Parent Advocate for NCLD. Leonard Press, OD is a board certified optometrist with specialty training in pediatrics and binocular vision. He has served as chief of the pediatric unit at the Eye Institute of the Pennsylvania College of Optometry and as Chief of the Vision Therapy Service at the State University of New York College of Optometry.

Dr. Fortenbacher’s Expert Opinion on Vision-Related Learning Problems

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We’re pleased to let you know that the interview that I did with our VHG colleague, Dr. Dan Fortenbacher on Vision-Related Learning Problems (VRLPs), was along the Most Watched items on the heavily trafficked Elsevier Practice Update Eyecare website this week!

That fact is largely due to the succinct manner in which Dr. Fortenbacher distilled the many clinical facets and considerations of VRLPs in his concise overview.  Our featured interview was published in the Expert Opinion section of Practice Update Eyecare on June 22, 2020.

If you already subscribe to the site, you can access the interview here.  Although we strongly encourage you to take advantage of this free service, we are also providing a separate direct access link provided at the courtesy of Elsevier.  For your convenience, here is  the transcript of the interview, which appears in its entirety on the Elsevier Practice Update Eyecare site as well.

Dr. Press: Hello. This is Dr. Leonard Press, Associate Editor for Elsevier’s PracticeUpdate for Eye Care. Today, I’m joined by Dr. Dan Fortenbacher. Dr. Fortenbacher received his Doctor of Optometry from the Michigan College of Optometry at Ferris State University in 1979.

His interest in developmental vision and rehabilitative vision therapy began early in his career, working with helping children who struggled with binocular vision problems and vision-related learning problems. In fact, it is vision-related learning problems that is going to be our topic today.

Dr. Fortenbacher is a Board Certified Fellow of COVD, the College of Optometrists and Vision Development, and lectures extensively on developmental vision, neuro-optometry, and vision therapy. Dr. Fortenbacher is a past-examiner for the International Examination Certification Board of COVD. He has served in several leadership positions on the state and national level.

He served as President of the International COVD in 2007 to 2008 and has developed models of innovation in the delivery of developmental binocular and neuro-optometric vision rehabilitative care.

In addition to his private practice in Grand Rapids and St. Joseph, Michigan, Dr. Fortenbacher is also a clinical professor at the Michigan College of Optometry at Ferris State University and an adjunct faculty position at the Southern College of Optometry, where he is the program supervisor for the WOW Vision Therapy and Rehabilitation Private Practice Residency. Dr. Fortenbacher, thank you for joining us today.

Dr. Fortenbacher: Thank you Dr. Press. It’s a pleasure to be with you.

Dr. Press: You’re welcome. Let’s start off by discussing what exactly do we mean by vision-related learning problems? I know that the American Optometric Association has a clinical practice guideline on the subject, but for those that aren’t familiar with the term, exactly what do we mean by that?

Dr. Fortenbacher: That’s a great question, because when we look at the entire genre of vision conditions, when we separate those out into categories, the first category we often think of is ocular disease. That’s an important aspect for all of our patients, to sort that out and rule out if there is any condition with ocular disease.

Another category falls into the refractive category the need for lenses to address and compensate for refractive error, and that’s important for all of our patients, as well. But in general terms, the majority of the patients that we see that fall into the vision-related learning problems category have healthy eyes and their refractive condition is not influencing that performance problem because they have their visual acuity up to 20/20.

We’re really referring now to a category of vision problems that are influenced by aspects of how well the individual can use their two eyes together: binocular vision; fixate and follow, whether eyes are spot to spot, that’s the ocular motor component; and then the focusing, or accommodative aspects, strength, accuracy and flexibility of accommodation.

Those three sensory motor areas, oftentimes referred to as visual efficiency categories, are the really important elements that have to do with how we can use our eyes to take in information. Then beyond that has to do with how well you can process that information, so visual perceptual abilities, the ability to make sense of what you see, is another important element of being able to read effectively, learn effectively, and then apply that to academic performance.

Then the third aspect has to do with your ability to integrate that with other sensory functions. Eye-hand coordination is one example, fine motor and gross motor skills, and it could fall into also vision and auditory processing or vision and balance skills.

All of these are part of the umbrella of what we’re referring to and very important that we sort that out when we’re working with our patients, and that’s, I think, what we’re going to be talking about today.

Dr. Press: You made an excellent point, that this has nothing to do with visual acuity or eyesight, and the common misconception that 20/20 means perfect vision clearly isn’t relevant to learning. For example, reading, when you read newspaper print, you can do that with 20/50 visual acuity. What types of vision problems, or how can vision problems specifically affect reading or other elements of academic performance?

Dr. Fortenbacher: I think that when we look at the term “vision” as it relates to reading and learning, it’s important to, of course, rule out any ocular disease or any visual acuity problems to begin with. But, as you said, the majority of the kids that we see have 20/20 and the issue isn’t with being able to see small. It’s about being able to see easy, to be able to see with the two eyes together. This is where, in the front end of the evaluation, the doctor really needs to take a thorough history to get an understanding for how the child is having difficulty. Now this could be just from the basics of blurred, double, you see words overlap, you have trouble with eyestrain headaches, or other areas that have to do with performance.

It also can get into—and this is where I would recommend for the viewers to check out the COVD Quality of Life Assessment Questionnaire, which is a 30-point items of categories that could be affecting a child, and they are graded from zero (never) to four (always). The nice thing about that is you get a profile and you can see where those symptoms fall in as to how they could relate to an individual’s performance, and then looking at the visual components of that.

Back to your question of visual acuity. The majority of kids that we see can see 20/20, but what they’re having trouble with is the ease of which they do a task, and usually it’s a near-centered visual task. They can see the small print, but they’re having trouble with using the two eyes together. That extra effort, if it isn’t working for them well enough, they can actually have overlapping images. They can have the strain and effort that it takes to sustain that, so that sustaining that binocular function makes a difference.

If they are fighting hard, they can make it work, but they pay the price usually in headaches and eyestrain, or they give up and then they have poor attention. That’s where you see some of the ADHD-like behaviors. That’s going to affect in the teaming, it can be affecting their focusing, as well as the tracking skills.

Dr. Press: The way you’re describing it—losing place, confusion, letters running into each other, blur, eyestrain—it sounds so intuitive that these would be impediments to reading and learning. Why is it, then, do you think that there is a certain amount of controversy or confusion since it seems relatively straightforward?

Dr. Fortenbacher: That is true. There is plenty of literature, plenty of research to show the connection between these sensory motor areas and reading performance. The difficulty, I think, comes into, where some of the confusion is, is that when the eye health professional, the eye doctor, is looking at that child from an eye disease model and a refractive model, that if you don’t dig just a little deeper into it, you can miss some of these fundamentals of sensory motor function.

Some of the tests that can be done by the optometrist or ophthalmologist are really quite basic just from a standpoint of evaluating the function of these three categories. One basic test is just called the “ near point of convergence test.” The examiner can use something as simple as an ink pen or a pencil. Or they could use a penlight and have the patient wear red-green glasses. But the most basic way to do it is just use a pen or pencil and move it on the z-axis towards the bridge of the patient’s nose and measuring at that point where they see it come apart or double.

What the research shows is the norm is 7 cms, about 2 to 3 inches, so anything beyond that would be indicative of convergence insufficiency condition. There are different gradations of that.

There’s other aspects of binocularity that has to do with your ability to sustain that fusion. That range of fusion is another important aspect. That gets into some of the more comprehensive tests we’re doing. But an examiner could also do this by just using, from their chairside, a prism bar. They could simply hold the target—again, it could be a pen or a pencil—and use this in front of the patient, base-out, and then flip it around and do base-in, and measure that range of fusion. There are norms established as to what would be acceptable at that distance.

Another simple test to do would be to ask the patient to fixate and follow on me and just watch it with their eyes while it moves. This tracking test is important to do that while the patient is observing. You also want to ask some simple questions, like, “Watching the beam or watching the pen, what’s your favorite color? Do you have any pets? What’s your favorite food?” These are some examples of cognitive loading. You’re looking at that performance while you’re adding a distraction, much like what they have to deal with in a classroom setting. A very simple test like that can be done in just a few seconds.

Then, finally, one that’s easy to do is just a prism flipper, a +2.00 or -2.00 flipper, while the target they’re looking at is a 20/30 print, just holding up a Snellen 20/30 and asking them to make it clear, tell you as soon as it’s clear. They should be able to clear that in about 1 to 2 seconds on each set of lenses over about five or six cycles, and that’s another accommodative flexibility test.

Those three areas are not that hard to test and very relevant to the categories that involve vision performance in reading and learning.

Dr. Press: It sounds like one of the main reasons that some of these areas are considered somewhat controversial is that people really aren’t teasing out, or looking at, problems in a way that you’ve suggested with some relatively easy screening tests or chairside tests can be uncovered. Do you think there might be any other reason? Are people reticent to delve deeper into this because they think there isn’t adequate research showing these interrelationships?

Dr. Fortenbacher: I think some of the confusion comes into play when we talk about vision reading when you look at the definition of reading. When we look at children having trouble with reading, we look at this as two general categories: the child who knows the words, but are having trouble reading quickly and understanding what they’re reading, so those are kind of the reading fluency issues versus the child that has a reading disability. Those are children who are significantly below where they should be for their age or grade level, and that is more into a more language base, but still problematic area for that child, sometimes referred to as dyslexia.

But that reading disability versus the reading fluency are two different categories. A lot of times when we talk about vision problems that affect reading, the assumption is if you fix the teaming, tracking, focusing, then suddenly your dyslexic child is going to now be able to read at age level. That’s not the case. They still need academic support. They need educational therapy or some other means to help them come up to speed in those areas.

But your child that has fluency problems, if they’re able to read at age and grade level, but they’re just losing their place due to ocular motor dysfunction, or they’re having trouble with words overlapping or seeing double, a combination of issues, you treat that and they can take right off. These are children that know how to read, but they have the inefficiency in reading due to the visual problem.

Part of the confusion, I think, is in the different areas, whether it be in education or in medicine, is not really understanding what we’re referring to when we say a reading problem. Both categories, a reading disability or reading fluency problems, can have vision problems that influence their performance, but the one that is the most, I would say, challenging are the ones that have the vision problems and dyslexia.

You need to fix or treat the vision problem and then collaborate with education therapists, reading tutors, to help them in their reading performance, and I think that’s where some of the confusion is.

Dr. Press: Perfect. I want to thank you for joining us today Dr. Fortenbacher. You certainly shed good light on what we mean by vision-related learning problems, how to detect them and how to manage them. We look forward to readers learning more about this subject on Elsevier’s PracticeUpdate Eye Care and other sources which we’ve related to. Thank you again, Dr. Fortenbacher.

Dr. Fortenbacher: My pleasure. Thank you, Dr. Press.

The Noise Ratio and Cognitive Load

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The impetus for this piece comes from an open access article in the March 2020 issue of Journal of Vision titled: Factors limiting sensitivity to binocular disparity in human vision: Evidence from a noise-masking approach.  One of the co-authors is Robert Hess, and thinking about him reminds me that Bob Sanet, Pilar Vergara, and I were scheduled to do a joint presentation at the COVD meeting in Canada this month on Amblyopia which was derailed by you-know-what.  One of the researchers whose work I was going to spend considerable time discussing was Robert Hess, an individual with an Optometry background who is Professor and Director of Research in the Department of Ophthalmology at McGill University.  But Hess isn’t a one trick pony — his research extends into many areas of vision, and you’ll enjoy checking out his lab’s home page.

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In the article above, Hess and colleagues refer to noise which, for our purposes, I’ll define as perturbation in vision that influences visual input or processing. If the source of the noise is the target or the environment we’ll call it external.  If it is within the individual’s visual system we’ll call it internal.  Examples of external noise include perturbation through stimulus changes in luminance, contrast, form, motion, and contour.  Sources of internal noise include changes in the ocular-motor, accommodation, vergence, and executive function systems.

Describing the influence of noise on stereo sensitivity, Hess and colleagues write:

“In noise-masking experiments, thresholds are typically unaffected by low levels of external noise. Once the external noise exceeds some critical value, however, thresholds increase linearly with its standard deviation. The transition point is the subject’s “equivalent internal noise” for performing the task. When the external noise is much smaller than the equivalent internal noise then performance is limited by the internal noise. When the external noise is much greater than the internal noise then performance is limited by that external noise.”


So let’s take the S’s to represent the various sources of noise in the external stimulus.  Now let’s take the Z’s to represent the tendency for you to fall asleep while reading this.  (Just wanted to see if you were paying attention!)  Seriously, let’s take the Z’s to represent the various sources of internal noise.  We know from studies in adaptive optics that aberrations can be purposeful, so it is safe to assume that some degree of noise is desirable (much as a certain degree of stress is purposeful).  Let’s assume that the idealized noise ratio of S/Z = 1.0.  Anything less that 1.0 would indicate that internal noise is predominating over external noise, and is more likely to degrade visual processing.


We know that through optometric vision therapy we can reduce internal noise, most readily through lenses, prisms, disparity processing and so forth, restoring the ratio closer to 1.0.  Hess and colleagues note that the visual system can compensate for noisier input by adjusting the efficiency of processing, but their analysis was conducted within the framework of the linear amplifier model. They chose this approach because … “it provides a simple method for analyzing noise-masking data, which appear to agree with the behavior expected according to that model.  It is almost certain that a full account of stereo sensitivity will require a model that is significantly more complex than the one we apply here.”

Cognitive Load Graphic

A more complex model, and one that would add to the non-linear amplifications that exist in the visual system, may reside in the cognitive elements of visual processing. Uploading or downloading the cognitive load during optometric vision therapy modulates noise ratio.  This may be one reason why scientists working in artificial intelligence have been so challenged to design visual systems that perform well in natural scene environments.  I and many others in our field have suggested that the extent to which we successfully incorporate cognitive loading is a significant factor in generalizing and transferring learning (optical as well as perceptual) to the patient’s activities and demands of daily living.