Latest JAMA research shows impact of Amblyopia/Lazy Eye runs deeper into children’s lives

In the November 2018 issue of the Journal of the American Medical Association (JAMA) Ophthalmology, in a paper entitled: Self-perception of School-Aged Children With Amblyopia and Its Association With Reading Speed and Motor Skills, the researchers from the Foundation of the Southwest, Dallas, Texas Department of Ophthalmology, came to an interesting conclusion. In this cross-sectional study conducted at the Pediatric Vision Laboratory of the Retina Foundation of the Southwest, from January 2016- June 2017, involving 81 healthy children grades 3rd – 8th, 50 with Amblyopia and 31 without amblyopia, researchers learned that those children with Amblyopia have lower self-perception associated with slower reading speed affecting their scholastic competence and poorer motor skills which affects the child in their athletic competence, social competence and behavioral conduct.

This paper was particularly interesting to me because for nearly four decades I’ve had the privilege to provide care in this specialty of optometry known as developmental vision and rehabilitation, working to help children (and adults) to improve in their vision development. I have examined and treated hundreds of children with amblyopia (lazy eye) observing them initially struggle with a lower sense confidence in ball sports, general athletic ability, and for many, academically due to slower reading speed and fluency errors. While this observation of lower self perception, prior to treatment is a relatively common theme, after binocular vision therapy when the child gains depth perception, better eye-hand coordination, visual tracking and overall visual development, it has been particularly gratifying to see them blossom in reading abilities, sports performance and self confidence.  

Now, thanks to Dr. Eileen Birch and the team of investigators at the Pediatric Laboratory of the Retina Foundation of the Southwest,  we have this new research that validates these observations and more importantly shows, or strongly infers, that we must look at Amblyopia as more than just reduced visual acuity in the affected amblyopic eye. We must understand the overall impact that Amblyopia has on a child’s perception of themself and how treatment must target not only visual acuity but also binocular vision, depth perception, oculomotor and saccadic eye movement.

While every child with Amblyopia should have a comprehensive eye health and vision evaluation with proper lenses prescribed as needed, it’s important to emphasize, as written in previous VisionHelp Blog posts, patching or Atropine drops (occlusion therapy) alone will not address these issues identified by the researchers in this JAMA- Ophthalmology paper. Here are the conclusions by the researchers:


  • “The association between self-perception of scholastic competence and reading speed, along with our prior finding that decreased reading speed in amblyopia results primarily from an abnormally large number of forward saccades suggests that Amblyopia treatment may improve the self-perception of scholastic competence.”
  • “Data showing that motor skills improve following Amblyopia treatment suggest that treatment may improve the self-perception of athletic and possibly social competence.”

Here is just more evidence to show that the best approach for treating the many visual components of Amblyopia requires a comprehensive model of care, beginning with a comprehensive eye health and vision evaluation and treatment including office-based optometric vision therapy emphasizing binocular vision (stereopsis), oculomotor skills and visual motor skills with a personalized approach to transfer the visual skills being developed into the life of the patient.

For a more detailed look into Amblyopia, diagnosis, advanced treatment and research, go to the VisionHelp Amblyopia Project.

Dan L. Fortenbacher, O.D., FCOVD

The Significance of Retina as Brain Tissue in the Context of Amblyopia

Academy San Antonio

Although recreation and relaxation in Arizona predominated for me this year over attending the meeting of the American Academy of Optometry in San Antonio, I would have loved to attend the session that was held yesterday afternoon.  From the program description:

Binocular Vision, Perception & Pediatric Optometry Section and Vision Science SIG Symposium: Lasker / IRRF Amblyopia Initiative – Where We’ve Been, Where We Are, and Where We’re Going.  This symposium will feature speakers involved in the Lasker/IRRF Initiative: Amblyopia – Challenges and Opportunities. The speakers will discuss recent progress on amblyopia research, the scientific hurdles that have been overcome, and what major questions now confront the field. Moderator: Susan Cotter, OD, MS, FAAO. Speakers: Kevin Duffy, PhD, Earl Smith, III, OD, PhD, FAAO, Benjamin Thompson, PhD, Ewa Niechwiej-Szwedo, PhD, and Ruth Manny, OD, PhD, FAAO.

You can gain a feel for what was discussed from a report published by the Lasker/IRRF Amblyopia Initiative last year — Amblyopia: Challenges and Opportunities.

Lasker Report Cover

There are several sections of the report that have particularly valuable sound bites.  The first relates to an appreciation of the retina as part of the brain.  I’m still hopeful that one of these days we’ll stop referring to “the eye and the brain”, and realize the significance of the eye as integral part of the brain.  So our first sound bit comes from the Concluding Remarks by John Dowling of Harvard’s Center for Brain Science (pages 111-112), who begins as follows:

“All agree that amblyopia is a disorder that affects visual structures beyond the eye. Many say simply that amblyopia is a brain disorder. But the retina is part of the brain, pushed out into the eye during development. As someone who has long studied the retina, I wonder if the retina is at all affected. At first glance, retinal function appears normal in amblyopia, but is it totally unaltered? I am not convinced …”

The second section involves the role of movement in amblyopia therapy (page 97):

“The potential of physical activity to promote amblyopic recovery has caught the attention of the clinical field. Adult subjects who intermittently cycled on a stationary bicycle while watching a movie showed enhanced effects of transient eye patching compared to those subjects who watched the movie while sitting still (Lunghi and Sale, 2015). Moreover, tasks that directly engage both visual and motor circuits have achieved great success in reversing amblyopia. For example, recovery from amblyopia is expedited by tasks requiring coordination of hand and eye movements, such as having patients manipulate objects during visual training (reviewed in Daw, 2013).”

Lastly, with the bolded emphasis mine (page 102):

  • “Novel visual training paradigms that exploit our increased understanding of the biological underpinnings of amblyopia recovery are needed. Future work should continue to seek training strategies that are tailored to the individual patient to engage attentional, emotional, and visuomotor circuits for faster and more effective recovery.”



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.

Screen Shot 2018-02-02 at 4.57.03 AM

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).

Amblyopia success…A family’s amazing vision therapy journey

When it comes to the topic of Amblyopia or “lazy eye”,  the VisionHelp Blog is a good resource for the latest information on diagnosis and advanced treatment. All you have to do is click here for a plethora of our posts!

But, how can you describe the emotional and personal experience that a family goes through, beginning when they first learn that their child has amblyopia followed by the entire process of going through vision therapy? Nothing could possibly say it better than this wonderful heartfelt video, produced by the parents of one of my patients, who wanted to help share their family’s amazing journey and lessons learned about vision therapy with the world. This is their child’s vision therapy success story. Many thanks to Chris and Cindy! 

For more information on the latest advanced treatment for Amblyopia check out VisionHelp Amblyopia Project.

Dan L. Fortenbacher, O.D. FCOVD


Elbow splinting increases amblyopia patching compliance…Really!!?

“Cutting edge” amblyopia research just announced, April 18, 2017, in Ophthalmology Times on Elbow splinting increases amblyopia patching compliance.

Yes, this story is true! It is not an attempt to fabricate the news or make a joke. It is a valid research article just published in the Eye Journal, Eye (2017) 31, 406–410. A quote from  the online article states, “…Elbow splints can increase children’s compliance with a patching regimen for amblyopia, researchers say.” A second quote further states, “…Adding elbow splints to the occlusion therapy regimen is an effective and parentally acceptable treatment method to ensure that all is done in order to try and improve vision in amblyopic eyes…”

The article further quotes previous research that says, “…people with uncorrected amblyopia have triple the risk of depression, double the risk of mortality and greater difficulties with day-to-day living…” This statement shows the seriousness of amblyopia. It is not just poor sight in one eye. It affects the entire quality of life of the person.

This statement confirms that the consequences of amblyopia extends much beyond reduced eye sight. But, does splinting a child’s arms to prevent them from removing an eye patch seem like a reasonable approach for treating amblyopia? Doesn’t this seem more like something right out of medieval times?

Indeed, amblyopia, often referred to as lazy eye, is a serious neuro-developmental vision problem that affects about 3% of people worldwide. The result of amblyopia is a loss of visual acuity in the affected eye due to a binocular vision dysfunction. In addition to loss of visual acuity in the amblyopic eye, the patient will have poor depth perception, poor eye hand coordination, poor visual processing and typically poor reading fluency. Historically the only treatment considered for amblyopia was occlusion therapy typically with an eye patch worn over the fellow eye. The problem with patching is that occlusion therapy has been found to be only moderately effective and riddled with negative consequences involving:

  • Eye sight improves with patching, but even with good compliance will often regress when discontinued
  • Patching does not treat the underlying cause of amblyopia which is due to a binocular vision problem
  • Occlusion as an overall treatment can have poor or marginal results
  • The child wearing an eye patch often experiences bullying, teasing, emotional upset, frustration, anger and general unhappiness
  • With patching there is a need of more parent attention associated with the child’s treatment

What do we now know? There is a much better way to treat amblyopia with superior outcomes, provides the patient with the opportunity to gain binocular vision and stereopsis (3-D) and does not require a daily eye patch (or Atropine) as a part of the treatment. This treatment protocol, including supporting research, is outlined for ophthalmologists, optometrists and the public on The VisionHelp Amblyopia Project.

Indeed the use of patching in the treatment for amblyopia has been around for over 100 years and considered to be the standard of care based on multiple amblyopia research projects in the past. But now there is a much better and modern “no patch” method  that does not require physical manipulation of the child to comply. Therefore, hasn’t the time come for health care of the 21st century to recognize occlusion therapy for what it is…a “dated approach”, not a modern medicine approach to a complex visual problem?

Come on!! Children with amblyopia deserve better care than elbow splints and an eye patch!

To learn more, here is a video that summarizes the modern approach to Amblyopia.

Dan L. Fortenbacher, O.D., FCOVD

The Necessity of Amblyopia and Amblyaudia


Put aside this article to read and came across it again this morning:  The Necessity of Amblyopia by Steven M. Archer, M.D., the 46th Richard G. Scobee Memorial Lecture presented as part of a Symposium of the Joint Meeting of the American Orthoptic Council, the American Association of Certified Orthoptists, and the American Academy of Ophthalmology, Las Vegas, Nevada, November 16, 2015, and published in the American Orthoptic Journal last year.

From the abstract:

“A general property of nervous system development is that correlated activity is used to organize topographic projections. This correlated activity is typically produced by electrical coupling of adjacent neurons; however, electrical coupling is not possible for retinal ganglion cells in separate eyes that need to be precisely mapped to the same place in the brain. This forces the visual system to rely on environmental stimuli to produce the correlated activity that drives the development of binocularity, with amblyopia as necessary consequence when visual experience is abnormal. The characteristic visual deficits in both the amblyopic and the sound eyes can be understood in the context of these normal developmental processes. The auditory system provides another example  where precise connections between paired sense organs must rely on environmental stimuli for normal development in which the analogous condition of amblyaudia occurs.”

Archer explains his premise in the introduction as follows:

“My thesis for this lecture is that amblyopia is not a result of visual system adaptation gone wrong, but rather a necessary consequence of a general strategy of nervous system development, well recognized in the field of neurobiology, that is left vulnerable to environmental disruption, in this special instance, by the physical separation of the two eyes.”


If the visual system relies on correlated activity from the environment,  how might this this neural activity between the two eyes work?  Archer suggests the following construct:


“Imagine an apartment building with a phone in each unit and walls that are not very soundproof. When you listen to the conversation on one of the phone lines coming out of the building, you hear not only the person in the unit from which that line comes, but also a little of the conversations going on in adjacent units. By listening to pairs of lines coming out of the building, you could ascertain which units are adjacent to each other and ultimately sort the lines into the same order as the units from which they came.  In the retina, correlated activity of adjacent ganglion cells could theoretically provide the information – analogous to the crosstalk between rooms in the apartment building needed to organize the projections to the lateral geniculate nucleus (LGN) and visual cortex.”  Watch these videos from the Kellogg Eye Center at the University of Michigan to see how this works.

Why is amblyopia truly a binocular problem?  Archer continues:

“Because the eyes are physically separated, there is no mechanism by which corresponding points in the two retinae can be electrically coupled to provide correlated activity. This means that if the same developmental strategy of using correlated activity is used to refine the alignment of the cortical maps, the correlation of corresponding retinal points in each eye will have to be generated by external visual stimulation of aligned eyes. So, while the projections from each eye are already largely retinotopic by the time of birth or eye opening, refining the binocular alignment of those projections must wait for visual stimulation. At that point, each cortical cell is influenced by both eyes as it establishes its spatial identity. It is most likely to pick a spatial identity that provides the best correlation between the inputs it receives from each eye. In this way, the mapping of each eye influences the organization of the other until they match.”

Parenthetically, Archer positions the loss of stereopsis as a barometer of the lack of refinement of binocular correspondence between the maps from each eye – something that persists even after surgical correction of ocular misalignment in the case of strabismus.  And given my penchant for the parallels between auditory and visual processing, I was drawn to Archer’s concluding paragraph:

“If organization of projections using information from correlated activity is a general feature of the developing nervous system, then are there other examples in which the function of paired sensory structures is vulnerable to abnormal environmental experience? As it turns out, the auditory system is similar in many regards. In a process analogous to stereopsis, differences in loudness and timing between the two ears are integrated centrally to localize sound in three dimensions. As with stereopsis, stereophonic sound gives a spatial sense of the environment that is qualitatively different from monaural hearing. Binaural hearing also facilitates the so-called “cocktail party effect” – the ability to focus on understanding one person speaking in a noisy environment – which may be particularly important for children in complex environments such as the classroom. A number of animal models show long-lasting functional deficits from monaural deprivation during a critical period development.  Clinical models of asymmetric hearing loss during childhood are more difficult to study, but there is growing recognition of an “aural preference syndrome” or “amblyaudia.”


Amblyopia and Reading Disorders

We’ve stated our case before that in many ways, a patient’s amblyopic eye may be considered as “learning disabled” relative to the non-amblyopia eye.  This was bolstered in part by an article showing that in strabismic amblyopia, reading is impaired not only during monocular viewing with the amblyopic eye, but also with the nonamblyopic eye and binocularly.  The impaired reading performance is associated with differences in both saccadic and fixational patterns, likely an adaptation to abnormal sensory experiences such as crowding and suppression.  This has also been reported in acquired conditions termed “amblyopic dyslexia“, and is consistent with our newly developed visionhelp Amblyopia Project.

Over the weekend I had the chance to sit down with an attractive new case-based textbook edited by Traboulsi and Utz containing a nice chapter on amblyopia.


There are some particularly nice sound bites from the chapter, including the following:

  • “Amblyopia is a neurodevelopmental disorder that occurs due to de-correlated binocular input to the visual cortex.”

(This squarely positions amblyopia more broadly as a neurodevelopmental problem worthy of deeper consideration than patching, atropinization or other approaches emphasizing monocular visual acuity as the main index of function.  It also identifies it as a binocular vision problem.)

  • “Although the first locus of dysfunction appears to occur in V1, abnormalities in the downstream extra-striate cortex have been shown by recent studies using neural recordings in animal models of amblyopia as well as psychophysical and functional MRI studies in humans.  Involvement of striate as well as extra-striate visual cortex can explain the spectrum of visual functional abnormalities that involve both the afferent and efferent visual systems and visual perception in amblyopia.”

(This paves the way for appreciating amblyopia at a broader level, including the continuum of visual deficits from acuity [V1] to extra-striate areas directly impacting reading abilities even in the presence of adequate visual acuity.)

  • “Dynamic retinoscopy should be completed to assess for hypo-accommodation, which may contribute to persistent amblyopia despite treatment.”

(There is a small but distinct chapter in the book dedicate to dynamic retinoscopy, and all I can say is Hallelujah! to the recognition of the importance of assessing and treating the accommodate system in amblyopia.)

  • “Lastly, vision loss in a structurally abnormal eye (w.g. one with optic nerve coloboma, optic nerve hypoplasia, retinopathy of prematurity) should not be assumed to be caused only by the structural anomaly, as there may be an additional component of treatable amblyopia caused by anisometropia, strabismus, or occlusion.  In such cases a trial of amblyopia therapy is indicated.”

(All too often amblyopia is dismissed as organic and the patient is never give the benefit of a trial period of vision therapy.  Rather than differentiating amblyopia into treatable and non-treatable buckets, this is a reminder that there may be a functional component to organic amblyopia worth treating even if the underlying structural abnormality doesn’t change.)

Back to the emphasis on reading disorders, the chapter has a nice table reproduced from the Vision Screening Recommendations of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS).  Here is a nugget, published in 2014, that previously escaped me.  Take a look at the very last item, and lo and behold there it is:

  • Refer children not reading at grade level







Dr. Susan Cotter on Amblyopia and Beyond

On behalf of the Editors at Elsevier’s Practice Update for Eyecare, we’re  very proud in continuing to feature the best that Optometry and Ophthalmology have to offer.


Published in Eye Care
Expert Opinion / Interview · December 03, 2015
Dr. Susan Cotter on Amblyopia and Beyond
Interview with Susan A Cotter OD, MS, FAAO Interview by Kathy F. Freeman OD, FAAO

Dr. Kathy Freeman of PracticeUpdate recently caught up with our guest, Dr. Susan A. Cotter, Professor of Optometry at the Southern California College of Optometry at Marshall B. Ketchum University, at the annual meeting of the American Academy of Ophthalmology (November 14–17, 2015; Las Vegas). Here they talk about the session that Dr. Cotter participated in, Amblyopia and Beyond: Current Evidence-Based Pediatric Eye Care.


Dr. Freeman: Welcome, Dr. Cotter. Tell us about your session; was it specifically concerning the PEDIG (Pediatric Eye Disease Investigator Group) studies?

Dr. Cotter: Thank you for having me. The session was the first-ever joint educational program sponsored by the American Academy of Optometry and the American Academy of Ophthalmology. This inaugural program was the result of a collaborative effort to support joint educational initiatives, and this particular symposium was the first step in this direction. We presented the same symposium at the American Academy of Optometry meeting in New Orleans (October 7–10, 2015), and now just presented it the second time here at the American Academy of Ophthalmology meeting.

The topic pertained to evidence-based pediatric eye care, and most of the evidence was based on the results from PEDIG studies. We discussed treatment of four conditions: amblyopia in younger children; amblyopia in older children; intermittent exotropia (IXT); and convergence insufficiency (CI). The discussions were based primarily on the results from PEDIG studies—both randomized clinical trials and large-scale observational studies.

Dr. Freeman: Would you give your impression of how you think the PEDIG studies have changed the way amblyopia is treated in practice?

Dr. Cotter: The results have impacted clinical practice in several ways. I think many practitioners now prescribe the child’s refractive correction first and wait to see how much (if any) treatment effect occurs from the optical correction alone over time before instituting any form of occlusion. Note that I’m not talking about the effect we get from eliminating blur from uncorrected refractive error. I’m talking about measuring best-corrected visual acuity through the refractive correction at dispensing and then having the patient wear the glasses or contact lenses to see how much treatment effect occurs over time before instituting any form of occlusion. Certainly, this has been a significant change in the way that I treat amblyopia, and it has been a change in other doctors’ practices as well. In fact, this was a question asked at the symposium, and the doctors who answered it (one a pediatric ophthalmologist and the other a pediatric optometrist) both said that prescribing the optical correction alone for a period of time was the biggest change in their clinical practices.

We see fairly good results over time from continued wear of the optimum refractive correction. On average, there is approximately a 3–LogMAR line improvement in amblyopic eye visual acuity. I think this is important because, from the child’s perspective, it’s a lot easier to patch with visual acuity that is 3 lines better than what the child had initially.

Dr. Freeman: What is the typical protocol to follow?

Dr. Cotter: Measure baseline visual acuity when you dispense the optical correction and follow the child out, say 4 to 8 weeks. If there is an improvement in visual acuity at the follow-up visit, then I typically instruct the patient to continue with the optical correction only until the next follow-up visit 4 to 8 weeks later. I continue to do this until visual acuity stops improving. If at this point, the patient still has residual amblyopia, then I institute some form of occlusion (typically, part-time patching or atropine).

Dr. Freeman: Well, it seems to me that it’s so much easier (for everyone) to initially put the glasses on a child, than to try to begin glasses as well as patching therapy at the same time.

Dr. Cotter: I agree—I think that one treatment at a time is much easier for many families. Also, think about it from a compliance perspective—if a child was 20/100 at baseline and, after a couple of months of wearing glasses, he/she is now 20/50, already the parents and child are encouraged about the visual acuity improvement in the amblyopic eye. The improvement found is not only motivating for the family, but it will now be easier for the child to patch with a 20/50 eye than with a 20/100 eye. So, it is likely to be less burdensome which might result in better overall compliance with treatment. It is a win–win all around.

In addition to prescribing refractive correction and occlusion sequentially, PEDIG study results have led to other changes in clinical practice. These other major changes include prescribing fewer hours of patching when prescribed, an increase in the use of atropine penalization of the sound eye, and treating older children.

Dr. Freeman: Dr. Cotter, from your perspective, how far-reaching is the impact of the PEDIG study results relative to amblyopia?

Dr. Cotter: There is interesting medical literature out there that says that it takes a while for healthcare providers to change their clinical treatment protocols, despite evidence that there might be more effective treatments than what they are currently prescribing. That said, I think that many eye care providers have changed the way they treat amblyopia. In particular, I think that the PEDIG study results have had a big impact within optometry. Most schools and colleges of optometry are PEDIG clinical sites, and therefore the results of the PEDIG studies are presented to the students just as fast as they’re published. If you think about it, the majority of our graduating students right now don’t know anything different about amblyopia treatment than what they are taught by their professors, most of whom happen to be PEDIG investigators. Thus, the majority of our students have never even heard of “full-time” occlusion being prescribed for amblyopia. And practicing optometrists who attend continuing education programs on amblyopia that are provided by PEDIG optometrists are also changing the way they treat amblyopia. I truly believe that the PEDIG studies have had a remarkable impact on the way the eye care community is treating amblyopia in 2015. I can’t speak as much for ophthalmology because I’m not as familiar with their training programs; however, many academic sites are involved in PEDIG and many of these programs are training pediatric ophthalmology fellows. So, there has to be some impact there as well.

Dr. Freeman: Are there any plans for the PEDIG investigators to study amblyopia intervention in young people beyond the age of 17 years?

Dr. Cotter: We’re not against studying older patients and it has come up as a possible study question, but we don’t have anything in the pipeline right now. However, it might be a bit difficult for PEDIG to conduct such a study because approximately two-thirds of our investigators are pediatric ophthalmologists, and they typically don’t see many adult patients. Thus, while there would certainly be some interest, sufficient recruitment for a study of adult amblyopia could be a potential problem.

Dr. Freeman: What about the dichoptic approach to amblyopia, with binocular video-gaming? Is there any interest in that from the PEDIG study group?

Dr. Cotter: Actually, we have an ongoing clinical trial, ATS-18, that is looking at that right now. The study population consists of children from 5 to less than 17 years of age. The children are randomized to either 2 hours of daily patching or 1 hour of binocular game play on an iPad.

The game, developed by Robert Hess and coworkers in Montreal, is a Tetris-like anti-suppression game. We already have about 350 children between the ages of 5 and 12 years who have been randomized. We were fortunate to reach our enrollment goal for the younger kids very quickly. Enrollment is still open, however, for children in the 13- to less than 17-year range. Our results for the younger cohort will likely be published sometime in 2016—so keep your ears open.

There is a lot of interest in this area of research, and we are dipping our toes in the water with ATS-18, which is the first large randomized clinical trial evaluating binocular anti-suppression therapy on the iPad.

Dr. Freeman: What would you say is the take-home message to the readership about the IXT portion of the symposium?

Dr. Cotter: The take-home is that, while we have published two papers reporting randomized clinical trial results on part-time patching for IXT, we still have a lot of unanswered questions in regard to other IXT treatments.

Our objective for the part-time patching study was to determine the effectiveness of this treatment for IXT in children. We found that, over a 6-month period, there was very little deterioration, defined as the IXT breaking down to a constant XT or a loss of near stereoacuity. While not everyone interprets the data from these papers exactly the same, we noted at the symposium that watchful waiting is a reasonable thing to do. My opinion is that we don’t have to rush young children off for surgery or even other forms of treatment because very few of these children with IXT had a decrease in their near stereoacuity or converted to a constant XT.

PEDIG is currently planning a randomized clinical trial for IXT, which is probably going to roll out in February; we are really excited about it. The goal of the trial is to evaluate the effect of overminus lenses for IXT, not only what happens short-term, but what happens long-term and whether there is a sustained effect once we take these kids out of overminus. PEDIG also has an ongoing randomized trial evaluating two surgical approaches for IXT.

Dr. Freeman: And what about CI?

Dr. Cotter: We discussed the Convergence Insufficiency Treatment Trial (CITT), how we interpreted the results, and how it impacted our treatment recommendations for symptomatic CI in children. We also discussed the results of a trial that PEDIG conducted called the CITS (Convergence Insufficiency Treatment Study), which compared home-based computer therapy versus pencil pushups. After discussing both studies, I also mentioned the on-going clinical trial, the Convergence Insufficiency Treatment Trial – Attention and Reading Trial (CITT-ART). There are eight clinical sites (optometry and ophthalmology) across the United States that are presently recruiting children 9 to 14 years of age with symptomatic CI; we’re in our second year of recruitment. The primary outcome measure is reading comprehension. Secondary outcome measures include other tests of reading comprehension, as well as attention. It was nice to be able to introduce the study to the audience and say, “Keep your eyes peeled, we’re going to have some interesting data in the next couple years to answer the question of whether treatment for symptomatic CI has an effect on reading performance in school-age children.”

Dr. Freeman: Well, all of this work that you’re doing seems to be making the appropriate treatment of these conditions so much easier for the primary care practitioner because you are really breaking it down into steps that can be easily instituted as therapy in an office without having to do a lot of traditional vision therapy.

Dr. Cotter: You know, that is another change I’ve noticed. I do a fair number of CE presentations, and one of the topics I’ve always lectured on is amblyopia. I feel that there are more primary care optometrists out there who are now comfortable with and willing to handle amblyopia in their practices versus 10 to 15 years ago. I think that this is because there is a strong evidence base for treatment, and it seems easier now that we know optical treatment and lesser amounts of patching are effective.

Dr. Freeman: Is there anything additional you would like to share with the readership about the important work you are doing with amblyopia and children’s vision?

Dr. Cotter: Yes, and thanks for asking. We would like for members of the eye care community to partner with us in our on-going studies by helping us recruit eligible children. So, I ask that all practitioners with offices in close proximity to our clinical sites refer patients from their practices who appear to be eligible for the studies.

There are certainly many docs who are not able to provide active vision therapy in their offices for kids with symptomatic CI, so referring them to the CITT-ART study is a win–win for everyone. Parents are usually very grateful to be referred to a NEI-funded clinical trial for which there is no cost to them. It actually makes the referring doc look good. And, of course, the patients will be sent back to the referring doctor’s office after the treatment. Likewise, there are docs who might not be comfortable with treating teenagers with amblyopia, and yet that teenager and his/her family might be very interested in enrolling in a study that is evaluating cutting-edge binocular amblyopia treatment on an iPad which is not presently commercially available. So, refer that patient to a PEDIG ATS-18 site!

Dr. Freeman: Where would an eye care provider go to find the sites or find how to refer somebody?

Dr. Cotter: For CITT-ART, the website is For PEDIG, people can go to to find out where the nearest PEDIG investigator is located and the studies that are currently recruiting. The website also has information about the trials.

Dr. Freeman: Anything else that you would like to add?

Dr. Cotter: Yes—I should mention that the views that I have expressed to you are mine only, and do not represent those of the PEDIG, the American Academy of Optometry, MBKU, or any other professional organization to which I belong.

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Amblyopia as a Developmental Disorder

I have blogged before about the elegant vision science definition, introduced by Levi, of amblyopia as a developmental disorder of spatial vision, and our colleague Dr. Fortenbacher has summarized the impact of amblyopia on quality of life.

Two very practical articles are now available that shed more light on this, published in the journal JAAPOS.JAAPOS

The first article appeared in the August 2015 issue, and is titled: Reading rate and Scantron completion time in children with amblyopia.  We commonly see adolescents in our practice who are seeking accommodations on standardized testing.  Amblyopia is a condition that is traditionally defined by a reduction in visual acuity with one eye, and it has been felt – particularly in ophthalmologic circles – that an ADL such as filling in answers on a Scantron sheet should not be impacted as long as both eyes are being used.  This article by Birch and colleagues lends support to viewing amblyopia as a visual disorder that can negatively impact visual function with both eyes open despite good acuity and the absence of strabismus.


The second article is also by Birch and colleagues, this time with Kelly as the lead author, and absent John F. Gillmore III.  The article hasn’t come out in the print edition of JAAPOS yet, but is available online, and is titled: Amblyopic children read more slowly than controls under natural, binocular reading conditions.   Again, this is a population of students who have amblyopia without strabismus, and there are several noteworthy comments in the Discussion section:

a) Reading is a vision-reliant ability and slow reading can be detrimental to academic performance and learning.

b) Under natural, binocular silent reading conditions, school-age amblyopic children read slowly.

c) Slow reading in amblyopic children appears to be a consequence of  oculomotor dysfunction.

d) Parents and educators of  amblyopic children may be unaware that a child’s reading is affected by amblyopia because the child has 20/20 vision when tested binocularly.

e) It is important to provide academic accommodations for children with amblyopia when warranted, and not just for children with bilateral visual impairment.


In their acknowledgement to the article, the authors cite Kenneth Ciuffreda and  Preethi Thiagarajan for loaning a ReadAlyzer to them for training and pilot work.



The Binocular Syndrome of Amblyopia – Part 2

The special September 2015 issue of Vision Research on the subject of Amblyopia as a window into visual cortex development and recovery of vision was introduced in Part 1.  The salient points of Part 1 can be summarized as follows:

  • Amblyopia is more than an acuity problem
  • Amblyopia is a binocular problem requiring binocular re-balancing therapy
  • Functional alterations in amblyopia extend beyond striate visual cortex resulting in widespread deficits
  • Amblyopia is best conceptualized as a binocular vision syndrome



The current wave of interest in research is welcome, and essentially updates Worth’s concept of how to treat amblyopia that dates back over a hundred years.  It was Worth who is credited for inventing the Amblyoscope, and it is worth noting that the essence of his haploscopic device was to treat amblyopia as a binocular problem, hence the name “Amblyoscope” as opposed to “Strabismoscope” or something primarily addressing misalignment of the eyes.  Worth intuitively realized the need for the patient to exercise control and provide awareness through the eye that did not function as well as the fellow eye.  Subsequent versions of the instrument were the troposcope and synoptophore whose names placed emphasis on alignment the eyes.  The ability to manipulate brightness and exposure rate of the image through the amblyopic eye to attain balance between the two eyes are among features still valiuable in amblyoscopes to this day.  Worth should receive his due for the prescient concept of treating amblyopia as a binocular problem.

Worth-Black Amblyoscope




As reviewed by Greenwald, Brock also expended much effort in promoting a binocular approach to amblyopia therapy.  Brock was innovative in designing procedures for both eyes that took the patient out of the instrument environment and helped transfer these skills into visual space.  This is also an opportunity to reiterate that although the current trend toward therapy for amblyopia has a distinctive binocular flavor, there are select cases for which a monocular foundation must still be built before bridging into binocular procedures.  Thus it would be premature to declare that the need for patching the fellow eye in amblyopia is ready for extinction.  However, much as atropine therapy serves as pharmacologic MFBF (monocular fixation in a binocular field), patching therapy when indicated should rapidly progress to the MFBF phase through translucent or selective filtration.

eye patch translucent & red

Were Worth and Brock brought back to some of the current binocular approaches to amblyopia and strabismus therapy, they would no doubt feel that they are back to the future.