New Research- Binocular Vision Therapy faster and better results in Amblyopia Treatment

When it comes to modern treatment of eye disease there is a strong emphasis in the current literature and continuing education on the latest and most advanced methods for quality patient care.

Surely, are there any ocular diseases or visually impairing conditions, such as cataracts, glaucoma or dry eye disease, where a doctor’s prescribed treatment approach centers around a method developed 100+ years ago?

The answer is none, except…Amblyopia. 

Amblyopia, otherwise known as Lazy Eye, is the most common form of monocular visual impairment affecting approximately 3% of the population worldwide. This condition is one that Dr. Leonard Press and I have blogged about extensively over the last 10 years on the VisionHelp Blog. Many of our posts on this topic describe, to some degree, our frustration with the persistence of  many doctors to solely prescribe the conventional 100+ year old treatment approach involving occlusion (eye patching) or penalization (atropine drops) of the fellow eye, when more modern and efficacious treatments are available. The modern treatment methods for amblyopia involve binocular vision therapy which treats the etiology of amblyopia beginning with a dysfunction of binocular vision causing suppression in the amblyopic eye. This has been documented extensively by the research of Dr. Robert Hess and many others during the last 20+ years. 

And now we have more new research that supports the premise that the best results for those with amblyopia is to prescribe binocular vision therapy along with traditional methods. To better explain, published on January 31, 2022 in the Open Access BMC Ophthalmology Journal, is the research paper entitled: Efficacy of vision therapy for unilateral refractive amblyopia in children aged 7-10 years. 

The author’s Conclusions state: “Vision therapy combined with conventional treatment (optical correction and part-time patching) is more effective than conventional treatment alone in children aged 7-10 years with unilateral refractive amblyopia. The treatment results in not only greater vision gain, but also in shorter duration of treatment.”

One particularly impressive aspect of this research paper was the thoroughness of the Discussion Section. Here the authors did an excellent job of addressing elements of the research design, for example, why this was a retrospective study vs a prospective study and how their conclusions were valid with this treatment group. 

Other examples outlined in the discussion had to do with emphasizing that their research design  was not a binocular vs monocular strategy in treatment, but rather a combination of the two compared to only a  monocular “patching strategy” in treatment. Once again, their research  evidence clearly showed  that better outcomes occur when the treatment targets the cause of amblyopia, that being a failure of binocular vision, with an emphasis to rehabilitate the binocular dysfunction as a vital component of the amblyopia patients treatment plan.

 

With more evidence now showing that the best method for patients with unilateral amblyopia is with binocular vision therapy as the foundation;  we are long overdue in placing a priority in modern patient care on the role of incorporating binocular vision therapy as the new “gold standard” in amblyopia management. The time has come.

Dan L. Fortenbacher, O.D.,FCOVD

Amblyopia/Lazy Eye – novel interview provides greater understanding for doctors and patients

When it comes to explaining Amblyopia, few doctors do it better than Dr. Leonard Press. As one of the world’s leading experts on developmental vision, Dr. Press answers questions with Dr. Paul Freeman, Eye Care Editor and Chief for Practice Update, on the topic of Current Concepts in Amblyopia Management. This video is one of a series of  interviews produced by Practice Update as a free online resource for healthcare professionals. The uniqueness of Dr. Press is his ability to explain this complex condition so that is understandable not just to doctors, but also to those patients, or parents of patients with Amblyopia.

Dan L. Fortenbacher, O.D., FCOVD

Adults with Amblyopia/Lazy Eye… effective treatment now

Amblyopia/Lazy Eye is a vision problem that affects both children and adults. This neurodevelopmental loss of vision, typically in one eye, begins in childhood and causes loss of eyesight, poor or no depth perception and many other problems including poor eye hand coordination and reduced reading speed and fluency. 

The cause of Amblyopia is clearly understood from decades of research to be a failure in binocular vision (both eyes working together), known as Suppression, that begins in infancy or early toddler-hood, normally due to strabismus (crossed or turned eye), known as Strabismic Amblyopia and/or refractive imbalance, known as Refractive Amblyopia or deprivation caused by congenital cataracts. But, regardless of cause, Amblyopia impacts the lives of all of those who suffer with it at all ages. 

The reason for the emphasis of focus on children historically has been because the standard treatment for Amblyopia, occlusion therapy (patching) has been determined to be effective up until approximately age 10. In fact, this is true when you look at the clinical trials that evaluate the efficacy of occlusion as the treatment. However, what new research  shows is that age is not a barrier to treatment for Amblyopia when the patient, even an adult patient, is participating in visually interesting techniques that are engaging and designed to decrease the suppression and “turn-on” the function of both eyes working together. This method of turning on both eyes working is known as binocular vision therapy.

Even though occlusion therapy has a host of negative side effects it is routinely prescribed because the volume of clinical research shows visual acuity can improve in young childhood.  But, what about the impact of patching on suppression? And does treating the problem of vision loss due to the origin of the amblyopia by “attacking” the suppression from a binocular vision therapy model work better than patching, regardless of age?

The answer to these questions and many more are addressed in a new paper, published in Frontiers in Neuroscience, January 2020, Volume 13,  entitled: Patching and Suppression in Amblyopia: One Mechanism or Two?, authors: Yiya Chen, Zhifen He, Yu Mao, Hao Chen, Jiawei Zhou and Robert F. Hess. 

The authors conducted a clinical trial to study the following:

  • The effect of occlusion therapy on patients’ visual acuity
  • The effect of occlusion therapy on patients’ suppression
  • The relationship between changes in visual acuity and suppression.

What the researchers concluded was that their findings were consistent with other studies regarding visual acuity and occlusion therapy. That is about 50% of patients’ visual acuity improved with occlusion therapy. But, they also concluded that even in those who had improved in visual acuity from occlusion therapy,  the problem with suppression did not change significantly. Therefore, those who did occlusion therapy still had a failure in binocular vision.

The authors further stated, “The notion that monocular occlusion therapy and binocular therapy might involve different neural mechanisms is in line with several other notable differences between the effects of these two therapeutic approaches.”

Now the reader may wonder, what does any of this have to do with adults with Amblyopia? The answer to this question can be found on page 8 of their paper. The authors went on to summarize, based on their own research and that of multiple other cited studies the following five conclusions:

  1. Occlusion therapy is only effective in children, but ineffective in adults. However, binocular vision therapy has been shown to be effective in adults and children with similar effectiveness.
  2. Better binocular outcomes have been achieved through binocular vision therapy than occlusion.
  3. The treatment duration is approximately 3-6 times faster with binocular vision therapy vs occlusion.
  4. The recurrence rate of amblyopia is high with occlusion but low with binocular vision therapy.
  5. Studies that have examined children who failed to improve in visual acuity after occlusion therapy actually showed improvement in their visual acuity after binocular vision therapy.

Given the fact that binocular vision therapy has been shown in research to be more effective at the cause of amblyopia, ie suppression, than occlusion therapy and given that binocular vision therapy is effective both in adults and children with similar effectiveness, plus is 3-6 times faster than occlusion therapy, what might we expect if the quality of the binocular vision therapy is advanced into a highly stimulative, visually engaging and enjoyable experience?

This is discussed extensively in our chapter published in the August 2018 3rd Volume, Issue 1 of Advances in Ophthalmology and Optometry entitled: Vision Therapy and Virtual Reality Applications, Drs. Fortenbacher, Bartolini, Dornbos, Tran where we present the latest developments in technology coupling the clinical research in neuroscience and brain neuroplasticity. This modern frontier of new therapeutic applications of highly motivating, patient-engaging binocular vision therapy brings into the next generation, even for adult patients, effective treatment for amblyopia with properly prescribed and supervised virtual reality (VR) in vision therapy.

Now bringing this into practical applications, for the last 5 years we have provided office-based vision therapy, utilizing Vivid Vision Virtual Reality as an integral element for our adult patients with amblyopia treatment with excellent outcomes. Our patients have gained dramatically improved depth perception, as well as visual acuity.

What’s more, during the last 2 years, we have dispensed home Vivid VR as a new addition to our at-home vision therapy regimen used in conjunction with our doctor and vision therapist guided office-based vision therapy sessions. In the home units, the patient can use their VR equipment anywhere they have access to WiFi where they literally toggle into our office computer, working on the same VR programs, just as if they were physically in our office. 

The advantages of these new technologies in vision rehabilitation and vision therapy have positioned adult patients, just as much as children, to now obtain effective treatment for their Amblyopia.  

Dan L. Fortenbacher, O.D., FCOVD

Why effective Amblyopia treatment requires binocular vision rehabilitation

Recognized as a significant vision problem that affects millions of people worldwide, one of the “hot topics” of  advocacy at the recent 2019 VisionHelp Annual Meeting  was Amblyopia. 

Amblyopia/Lazy eye is a serious neurodevelopmental vision problem that causes vision loss in approximately 2-4% of the population or 1 in 30 people. Neuroscience has shown that Amblyopia occurs when there is a unilateral failure in binocular vision, occurring early in life typically infancy or toddlerhood.

When the binocular system is broken at a young age, a neuroadaptation occurs, known as suppression where the signal from one eye is “shut down” by the brain to counteract the confusion created by the broken binocular system. As a result of this unilateral failure of binocular function a cascade of delayed visual function occurs leading to the following:

  1. Reduced visual acuity (eye sight) in one eye
  2. Reduced, or no stereo acuity (depth perception)
  3. Poor saccadic eye movement 
  4. Poor visual processing ability
  5. Poor eye hand coordination

Thus, due to a failure in binocular vision, a spiral of visual problems occurs that is much more involved than visual acuity of one eye. But, because visual acuity is reduced in one eye even with best correction, Amblyopia is one condition in optometry and ophthalmology that should never be misdiagnosed or overlooked.

The issue presented at VisionHelp 2019 was, in spite of the obvious hard to miss diagnosis of Amblyopia, as well as the impact of a failed binocular visual system on a patient’s life that supersedes the visual acuity loss in one eye, there is a need to improve professional and public understanding for effective Amblyopia management.

Indeed, even though patching for Amblyopia has been around for 300 years, it still is touted on many notable sources to be the treatment of choice for amblyopia. In fact, patching the non-amblyopic eye, either part-time or full-time, is evidence-based and outlined in various PEDIG Amblyopia Treatment Study (ATS) research clinical trials. These ATS clinical trials have shown a moderate amount of improvements in the visual acuity function of the amblyopic eye with occlusion therapy. However, what the PEDIG ATS research doesn’t show is that patching has a multitude of negative side-effects that are outlined in several other research papers. In addition visual acuity gains often regress when the treatment ends, plus and even more important, patching does not repair the broken binocular visual system which is the underlying cause for patient’s amblyopia.

It should seem fairly obvious that you can not repair a broken binocular system by patching an eye. Patching only re-enforces the failure of binocular vision. Therefore, 3-D, depth perception, ie stereo acuity, which is a measure of the quality of binocular vision, is ignored when a patient is sent home to wear an eye patch.

Therefore, using an occlusion-based model of treatment, stereo acuity does not develop nor do the related other conditions involving poor micro eye movement, poor visual processing and poor eye hand coordination.

Additionally, while there have been recent studies that have tried to explore binocular vision treatment for amblyopia, (PEDIG ATS-18) due the treatment design centered around a home-based model with once a month office monitoring (for 16 weeks), compliance by the patient was very poor resulting in less than optimal outcomes. Even though previous clinical trials exploring the best modality of delivery of care has proven that home-based models are no more effective than a placebo, the investigators of the recent PEDIG ATS-18 study presumably made the assumption that  a home-based model of treatment, with once every 4 weeks office monitoring, would somehow substitute for the professional guidance of an office-based model and get better compliance presumably because the binocular activity was an iPad game.

So, it was no surprise that with only once a month visits to the clinic over 16 weeks,  the compliance results for the two age categories being studied with the binocular video game were substantially below the required time to get results. For the two groups studied, age 5-12 year old, the compliance was 22% and for the 13-18 year old the compliance dropped to 13%.

Yet, instead of showing that the research subjects did not follow the prescribed dosing time, based on guidelines set by previous cohort studies, they simply concluded that binocular vision therapy was not effective. 

In conclusion, it’s important for professionals and patients to understand that the loss of monocular best corrected eyesight in Amblyopia is due to a broken binocular system. Due to this failure in binocular vision, effective treatment must include the vision rehabilitation of visual processing, oculomotor/saccadic eye movement, eye-hand coordination that begins with vision rehabilitation of the binocular visual system. The progress in vision rehabilitation should be measured not just based on visual acuity, but also stereo acuity and specific tests of visual processing and eye-hand coordination. Furthermore, research shows that effective developmental vision rehabilitation must be office-based with home support that is closely monitored and altered as needed to get consistent compliance and results. 

The VisionHelp Guidelines show that for treatment to be most effective, the following is recommended:

  1. To establish the diagnosis and various elements of treatment, the patient must have a comprehensive developmental vision evaluation including eye health, refraction, establishing optimal lenses for best corrected visual acuity,  binocular vision assessment, including measure of stereo acuity, oculomotor assessment, visual perceptual evaluation, and visual motor integration evaluation.
  2. Prescribed treatment should be 45-60 minutes office-based vision therapy, 1-2 times per week, with 1 hour per day of home activities that require close support by the supervising doctor and/or vision therapist.
  3. Home activities must have sufficient novelty and high level binocular stimulation including stereo acuity development. (examples: virtual reality in vision therapy
  4. Weekly progress on visual acuity, sensory fusion, suppression zone, stereo acuity. When these areas are not making expected progress the treatment activities and compliance must be carefully analysed with proper adjustments made to bring about improvements. 

Only when the complexity of Amblyopia is addressed with a comprehensive developmental vision rehabilitation delivery of care model, will patients have the chance to have successful outcomes in their amblyopia treatment. We must begin to realize that the best care for patients with amblyopia goes beyond patching.

For more information, the VisionHelp Amblyopia Project provides treatment protocols for most effective results.

Dan L. Fortenbacher, O.D.,FCOVD

The New Paradigm in Amblyopia Therapy

The utility of occlusion for binocular dysfunction is limited to patients for whom binocular vision is too confusing due to constant or variable diplopia. Oft times these patients will be responsive to vision therapy, lenses, prisms, syntonics or other therapeutic interventions but, in those rare instances when it is not, the tradeoff of losing half of one’s visual field in occlusion is worth the relief to the brain of trying to suspend or de-tune the troublesome second image.  In many instances diplopia can be sufficiently alleviated by spot or sector occlusion rather than total occlusion, thereby preserving peripheral vision in both eyes.

This does not apply to amblyopia, for which occlusion leads to con-fusion, as our colleague Dr. Dan Fortenbacher demonstrated in his presentation on advanced treatment of amblyopia six years ago.

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By con-fusion we mean that any time the patient is patched, we’re sending the brain a negative message counter to binocular vision.  That is illogical now that the consensus in vision science is that the source of amblyopia itself is a disruption to binocular vision and, as recently reviewed by Kraus and Culican, the depth of amblyopia is positively correlated to the degree of binocular imbalance.  Can you think of another form of therapy for which the mainstay of treatment is the source of the problem?  Neither can I, and that is the fundamental reason why the paradigm in amblyopia therapy has shifted from a focus on the amblyopic eye to emphasis on binocular integration.

In 2012 Dr. Daniel Press and I co-authored a paper that followed the methodology of Dr. Anrold Sherman who who reverse engineered hyperopic anisometropic refractive amblyopia.  Dr. Sherman originally termed the condition Adaptive Refractive Error Syndrome which he considered to be the origin of refractive amblyopia.  In a subsequent paper that provided his rationale for undercorrecting the eye with more ametropia, and treating the condition without occlusion, Dr. Sherman writes:  “If binocular interference is the major etiological factor in amblyopia development, treatment must be designed to eliminate it and achieve binocular cooperation.”

Scientific Reports Logo

As reviewed by Zhao et al in Scientific Reports, visual acuity is widely used in the diagnosis of amblyopia and has traditionally been the metric most valued by clinicians.  They demonstrate that although occlusion can aid in the recovery of some visual functions including visual acuity, stereo vision, and binocular rivalry at low spatial frequency, many other binocular visual functions remain deficient including binocular rivalry at high spatial frequencies, interocular summation, and interocular phase combination.  While their results support the observation that occlusion treatment is not sufficient to recover all the visual functions in amblyopia, and that additional treatment is necessary,  the new paradigm goes a step further in stating that for many forms of amblyopia, occlusion is actually counterproductive.  If occlusion has any remaining application, it may reside in rapid alternating occlusion and flicker therapy as published by Vera-Diaz and colleagues.

The final nail in the coffin of occlusion therapy may be emanating from research at the SUNY College of Optometry addressing the brightness deficit in amblyopia.

Journal of Neuroscience

Published this month in the Journal of Neuroscience, the SUNY research shows that amblyopia increases visual dark dominance by three to ten times, and that the increase in dark dominance is strongly correlated with the severity of amblyopia.  The implication of this research is that one of the keys to effective amblyopia therapy involves ameliorating the brightness deficit in amblyopia.  In that regard, occlusion is counterproductive because it reduces brightness.  One of the reasons that two eyes are better than one, even  on a task as basic as visual acuity (for example OU acuity vs. OD or OS on the Snellen Chart) is a boost in brightness perception due to binocular summation.

How do we boost brightness perception through the amblyopic eye?  Bear in mind that Claud Worth, over a hundred years ago, invented the Amblyoscope as a device that emphasized ways to improve vision through the amblyopic eye.  He didn’t call it a Strabismoscope or a Troposcope, which placed emphasis on the motor misalignment in strabismic amblyopia.  He was interested in rehabilitating the sensory deficits in amblyopia which, as it turns out, occur at the neural or cortical levels.  Clement Clarke did a better job than American Optical with terminology in that regard, changing the name of its device to Synoptophore, the “Syn” signaling togetherness of the eyes, parenthetically calling it the Major Amblyoscope.  The major advancement over Worth’s device was the ability to boost brightness to the amblyopic eye, and engage in what more recently has been termed the “push-pull” balance between the amblyopic and fellow eye.

On a final note, in bypassing occlusion we may be trading off a final outcome that in select cases would be better if occlusion were “judiciously applied”, much as one would judiciously apply lenses or prisms.  The patient with unilateral strabismic amblyopia typically has some degree of eccentric fixation.  Monocular activities such as Haidinger Brush done while the non-amblyopic eye is occluded are usually necessary to adequately stimulate foveal fixation that provides 20/20 rather than something a bit less.  But the patient or parent who is compromised by amblyopia and has improved considerably not only in visual acuity, but in many aspects of life really doesn’t care whether they end up with 20/20 unless we make that the sine qua non of a “cure”.  Much as the patient with strabismus really doesn’t know or care if she has anomalous or normal correspondence, the patient with amblyopia doesn’t know or care if she has eccentric or central fixation.  As a wise patient said to me many years ago: “You don’t have to make it perfect, doc.  You just have to make it better.”

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

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 ModernMedicine.com: 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

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.

scantron.jpg

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.

Readalyzer

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 1

In May of this year, Dr. Dan Fortenbacher updated us on some of the latest research into amblyopia.  Extending that, I highly commend to you the September issue of Vision Research, an international journal for the functional aspects of vision.  The special issue is titled Amblyopia: A window into visual cortex development and recovery of vision.

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Virtually every article is a gem, beginning with the Preface to this special issue by its Guest Editors,
Benjamin Thompson, Susana T.L. Chung, Lynne Kiorpes, Timothy Ledgeway, and Paul V. McGraw.  They state in the opening paragraph that amblyopia is characterized by a loss of visual acuity in the affected eye and impaired or absent binocular visual function.  This theme that amblyopia is a binocular problem recurs throughout the issue, and sets the stage for updated thinking regarding treatment that moves well beyond patching.  A few other statements and concepts caught my eye:

  1. Amblyopia represents the most common cause of visual impairment in childhood and has a significant impact on qualify of life.
  2. It is suggested that amblyopia may alter the white matter property of early visual pathways.
  3. The impact of amblyopia is not limited to the primary visual cortex, but extends to extra striate visual cortex.
  4. Suboptimal pooling of neural information from the amblyopia eye within V1 and V2 is a potential mechanism for a reduction in the relative proportion of signals to extrastriate areas.
  5. Characteristics of fixational eye movement abnormalities limits visual stability and acuity.
  6. Amblyopia disrupts visuo-motor coordination, and difficulties in acquiring reliable visual information regarding the shape and location of target objects appear to play a role in the visuo-motor deficits associated with amblyopia.
  7. Impairments in motion-defined form perception and multiple object tracking occurs not only in the amblyopic eye, but in the fellow eye.
  8. Crucially, these deficits were not improved by occlusion therapy, even when the acuity of the amblyopic eye improved significantly.
  9. A binocular approach to amblyopia therapy, particularly when embedded in a video game format, resulted in significant improvements in visual acuity, stereopsis, contrast sensitivity and reading speed.
  10. Taken together, these items underscore that amblyopia is more than an eye problem.  Amblyopia should be viewed as a syndrome manifest as a diffuse brain problem in the visual pathways leading to and beyond the striate cortex with disruption in overall performance.

Perhaps the strongest clinical article in this special issue is the first one, Amblyopia and the binocular approach to its therapy, by Robert Hess and Benjamin Thompson.  It is important to note that in their binocular approach to therapy, no patients have reported diplopia because they are always working under conditions where fusion is operating.  However as they note, their approach to date has been limited to patients with anisometropic amblyopia or small angle strabismic amblyopia characterized as less than 10 prism diopters.  It is Hess and Thompson who refer to amblyopia as a syndrome, and make the following statement:  “Suppression is an important part of the amblyopia syndrome and the positive correlation between suppression and the depth of amblyopia indicates that binocular dysfunction is the primary problem.”

I very much like the terminology that Hess and Thompson use in referring to their therapeutic approach as binocular re-balancing therapy.  They refer readers to earlier behavioral optometric approaches, referenced to an article I authored in the COVD journal in 1981.  I explored these connections a bit further here a few months ago.