Pediatric Screening



Amblyopia, often referred to as 'lazy eye', and the related condition strabismus (misaligned eyes) affect 5% of the world’s children, but go undetected approximately 50% of the time because only obvious cases are readily identified. If not treated by the age of 7, vision in the affected eye is permanently lost. These conditions are the leading causes of preventable vision loss in the United States and worldwide.

The method to correct such problems is often the use of a simple $1 eye patch, and in some cases eyeglasses or surgery. The problem afflicting primary care providers and parents, however, has been identifying the children who need treatment. The signs of the conditions are not always visible even to a trained physician, and available screening measures have been ineffective. 

But REBIScan has developed a solution: the Pediatric Vision Scanner (PVS). This portable, handheld device uses a new technology — retinal birefringence scanning— to detect amblyopia and strabismus when they develop. The PVS will reduce false referrals to eye-specialists while improving detection of disease and bringing children to care earlier, thereby eliminating vision loss from amblyopia. The PVS received de novo clearance from the Food and Drug Administration (FDA) in June 2016.


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Amblyopia and strabismus affect 3–5% of the US population, with studies showing that only 1/3 of pre-school children in the United States receive any form of vision screening. Strabismus can disturb normal interpersonal interactions, resulting in poor self-esteem, social anxiety, and phobias. Strabismus, amblyopia, and the loss of binocular vision also limit employment options, leading to productivity costs to society.

Primary care physicians have struggled to consistently detect and diagnose strabismus and amblyopia because often the signs of the disorders cannot be detected even by competent, trained providers. These physicians are vulnerable to medical malpractice litigation if they fail to detect eye conditions, but they consume excess healthcare resources if they refer children with normal vision to a specialist. 

Researchers estimate that the direct cost of the conditions in America is over $1 billion per year. This is related to both missed diagnoses (leading to longer and costlier follow up examinations) and referrals of healthy children to specialists (resulting in wasted insurance spend and patient co-pays.) In America, approximately half of all cases are missed. Globally, it is estimated that 35-40 million children are affected by the condition.

While successful surgical intervention can have profound benefits for some individuals, late intervention combined with poor understanding of the pathogenesis of strabismus produces disappointing long-term surgical results, with only about half of patients who undergo surgery for strabismus ending up with satisfactory alignment 8-10 years later. Implementation of REBIScan's PVS device will shift care delivery to a preventative stage where disease is manageable, affordable, and correctable.

The state of the art today for most primary care providers is the same visual acuity testing that was used in the 1800’s: A child reads letters or symbols on an eye chart. This testing requires a verbal, literate, cooperative child, meaning it cannot be performed until a child is 4–5 years old when treatment is less likely to be effective. Even at age 5 and above, the results of visual acuity testing are often inaccurate.

Automated refraction or photoscreening methods have been developed as an alternative, but they falsely refer hundreds of thousands of children, while missing an equal number of cases. The American Association for Pediatric Ophthalmology and Strabismus (AAPOS) has established referral criteria for photoscreening technologies, but at least one study suggests that only 1 of 8 children referred by photoscreeners have, or develop, amblyopia. These competing technologies seek out risk factors for amblyopia and strabismus, while REBIScan’s technology detects disease at its earliest stages. 

The Pediatric Vision Scanner (PVS) is a hand-held device that detects disease in a 2.5 second scan of the eyes. It provides accurate, unambiguous readings in children as young as the age of 2, and can be operated by administrative office staff. 

The key technology behind the PVS is retinal birefringence scanning. This patented technique, which was co-invented by REBIScan co-founder Dr. David Hunter, works by scanning the eyes with a circular beam of low-intensity, polarized laser light and analyzing the reflected signal. 

Over 20 years of research have contributed to the development of the device. One independent study of the PVS demonstrated 94% accuracy, allowing users to catch amblyopia and strabismus when they are most cost-effective to treat. Another study showed 97% sensitivity and 100% specificity, the highest accuracy ever reported for a screening device for these disorders.

Our partners in developing the PVS (click on each to learn more):
BCH transparent realJHU transparent real uploadYour Practice transparent real upload

At REBIScan we foresee a day in the very near future where all children under the age of 8 will receive a PVS scan during their annual well-child visit, as well as during any visit to an eye-specialist. The result will be the early detection and treatment of all children with amblyopia and strabismus, and the eradication of severe vision loss from the #1 theft of sight in children and adults.

Screenshot 2016-07-27 15.57.46

 These goals bring with them sizable impacts for all the stakeholders involved. Based upon analyzed data within published literature, the PVS could save insurers between $250 million and $1.0 billion annually. 

Adoption of the PVS could also generate significant new revenue to the adopting clinics. Researchers estimate that the average eye clinic could annually generate between $12,000-$28,000 in new revenue through adoption of the PVS, while primary care clinics could generate between $8,000-$200,000 annually in new revenue. Screenshot 2016-07-27 15.58.36


Additional Thoughts

At REBIScan, we closely monitor developments in the fight against eye disorders and the push to improve early vision screening in children. Look under the tabs below for thoughts on amblyopia, strabismus, and REBIScan's work from REBIScan cofounders Justin Shaka and Dr. David Hunter, MD, PhD.

Amblyopia – the name is hard to read, hard to pronounce, and poorly understood – yet the condition with the misnomer “lazy eye” steals sight in hundreds of thousands of children in the United States (and millions worldwide) every year. The good news is that IF amblyopia is diagnosed early enough, it can be treated with a simple eye patch (or an eye drop for kids who will not wear a patch.) But if it is missed – and it is missed frequently – no amount of glasses, patching, eyedrops, or surgery can bring the eye that has lost vision back to normal. As a pediatric ophthalmologist I care for children with amblyopia, and the sad news is that I routinely treat young patients who get to me too late in life for treatment to recover normal vision in the amblyopic eye. For them this means lost career opportunities, a higher likelihood of anxiety and depression, and a much higher chance of becoming blind in both eyes at some point in life. To me, the number of children affected – up to 5% of the population with vision loss that could have been prevented – constitutes a public health catastrophe.

What to do? Well, in addition to my work as a clinician, I also happen to be an engineer and researcher, and I have devoted much of my career to finding a technological solution to help primary care doctors detect amblyopia long before children reach school age. I believe that we have found that solution by means of a safe and simple retinal scan, and that is why I cofounded REBIScan. We have a product, now in the final stages of commercial development, that we are confident will lead to early detection and eradication of this silent theft of sight. In these pages I will share the challenges I face educating the public about amblyopia, teaching other doctors about why our technology is superior, being part of a startup company, developing a new product, and raising money to make it all happen. In short, you will learn about amblyopia and one doctor’s quest to change the standard of care in pediatric vision screening.

— David G. Hunter, MD, PhD


Shultz, Charles. Security is an Eye Patch. US Public Health Service Publication No 1770. Arlington, VA: US Government Printing Office, 1968.

Back in 1968, the United States Public Health Service reprinted a series of Charles Shultz’ “Peanuts” cartoons in which Charlie Brown performed a home eye exam on his little sister, Sally, and discovered that she had amblyopia. The booklet, titled “Security is an Eye Patch,” was made available to the public for just 15 cents a copy in an effort to promote awareness of amblyopia. The panels addressed many of the challenges that we face today in the detection and treatment of the condition.Charlie Brown home eye test 2Amblyopia ex anopsia

Why do they call it “Lazy Eye?” The literal translation of “amblyopia” is “blunt sight.” It is unfortunate that we have adopted an unpronounceable and off-putting term for such an important, sight-threatening condition, as I believe the word makes the condition far more unapproachable than it needs to be. Amblyopia is caused when one eye is deprived of normal visual input during the critical developmental years. The deprivation can be the result of asymmetric focus, a misaligned eye (strabismus), or a congenital malformation blocking formation of a focused image. The term “lazy eye” came about because the eye with poor vision was thought to be not “working” to give a good image to the brain. This is an unfortunate misnomer - the eye is not “lazy,” the eye is working as hard as the other eye, but the brain has been starved for visual input from that eye and so it never learned how to interpret the information that the eye is sending. Instead of calling it a “lazy eye” we should call it a “starving eye” or “starving visual cortex.”  Recent research shows that once the visual acuity in one eye is reduced by amblyopia, the other eye actively prevents it from recovering. Thus, a starving brain needs to be fed – with visual input, that is, while input from the better-seeing eye is reduced.

Home eye testing by charlie brownEarly Detection is a Must. Charlie Brown had it right here – testing for amblyopia at an early age is important. If the reduced vision is not discovered early in life – preferably in preschool – then the brain matures and treatment to restore vision will not be effective. Unfortunately, the test Charlie Brown used – in this case, the “tumbling E test,” requires a cooperative subject and is prone to errors. By the time children are old enough to cooperate for visual acuity testing using an eye chart with ordinary letters, they may be too old for amblyopia treatment to be effective.Charlie brown visual acuity chart

This raises a question: Why had Sally’s pediatrician left vision screening in Charlie Brown’s hands? Well, Sally was not alone – even today, only about 40% of pediatricians attempt any sort of vision screening in children under age 5. And for good reason - they have neither the time nor the equipment to perform a proper vision screening, and in many cases there is no extra reimbursement for the additional testing. Here, Sally is using her fingers to cover one eye, which means that it would be very easy for her to accidentally peek through her fingers to read the letters with the occluded eye. I have seen many patients with permanent vision loss from amblyopia who tell me later in life that they “cheated” on their eye test by peeking through their fingers, or by memorizing the letters on the chart, delaying diagnosis and treatment until it was too late.

How patching worksWear an eye patch for 6 months


Simple Treatment for a Lifetime of Sight. As Sally says, the treatment for amblyopia can be quite simple, but that is only IF she will cooperate and wear the eye patch as directed. Today we have abandoned the pirate’s patch Sally is wearing (it is too easy for a young child to remove), and replaced it with an adhesive patch or, in older children who are wearing glasses, a fabric patch. For kids who rip the patch off, there is another method that also works – a drop of atropine to dilate and blur the better-seeing eye as effectively as an eye patch. This means that even if a child is not cooperative, early treatment should be effective at restoring vision. Linus articulates the benefits of early treatment nicely:

Linus defines benefits of treatment

Universal vision screeningWhat about Universal Screening?  Sally might have also received a "D" from public health resource utilization experts, who advise against universal eye examinations. In some states, a specialist examination is mandated at the time a child enters school – already too late for the most effective treatment of amblyopia. Instead of sending every child for an eye exam, effective vision screening in the medical home will be the most cost-effective way to manage amblyopia. I will write more about the current approaches to vision screening in future posts, but our company, REBIScan, is developing a quick and highly accurate test that will allow pediatricians to detect amblyopia in preschool children when it develops.

We have brought amblyopia to its kneesThe Past and the Future. How far have we come in the years since Security is an Eye Patch was published? Not very. We are using (or not using) the same ineffective detection schemes and for the most part the same treatment. We are continuing to fail our children by allowing amblyopia to go undetected and untreated. Some insurance companies continue to ignore recommendations that pediatricians should be reimbursed for the extra time or equipment required for vision screening. It is time for a change - with early detection and early treatment we can see the eradication of permanent vision loss from amblyopia in our lifetime. When that happens, then all children will have the opportunity to share Sally’s triumph.

— David G. Hunter, MD, PhD

In an article published in JAMA Ophthalmology, a team of UCLA doctors that included Stacy Pineles, MD and Joseph Demer, MD, PhD found that having a misaligned eye can reduce the vision in the straight eye. In the article, they explain that, ”strabismus impairs visual function more than previously appreciated” explaining why patients whose eyes do not line up perfectly will often close one eye to see better. There is also ample evidence that amblyopia can reduce visual function in both eyes, not just in the so-called “lazy” eye. I have seen this in my own patients and found it to be true in some of my own research work – I was surprised to find that the eye with supposedly normal vision could not fixate accurately on a letter. The evidence for this problem continues to mount. Dr. Agnes Wong and colleagues at the Hospital for Sick Children in Toronto discovered other ways in which the amblyopic eye is holding back the fellow eye.

The full extent of limitations caused by a problem with vision or alignment of one eye is not always obvious to children or adults who suffer from strabismus or amblyopia, since they have had to live with the condition since childhood. Just as having one injured leg can impair the function of both legs together, so can having one malfunctioning eye reduce the function of both eyes together. This new research is more evidence that early detection and early treatment of both amblyopia and strabismus can give a lifelong improvement in the overall quality of life - even if (at first glance) only one eye seems to be affected.

— David G. Hunter, MD, PhD, REBIScan Cofounder

A few years ago I was listening to an NPR story (about how President Obama had been favoring former Treasury secretary Larry Summers over economist Janet Yellen to be the next Chair of the Federal Reserve) and I heard an unexpected reference to strabismus. Terry O’Neill, president for the National Organization for Women (NOW), said,

“The White House is indicating that the president would pass over the better-qualified woman for a less qualified man…. This is something that women have seen over and over and over and over again and it makes us cross-eyed with frustration.”

Ms. O'Neill's casual comment, which she repeated to Buzzfeed, disparages those who suffer from strabismus. It was made by someone who — of all people, the president of NOW — should know better than to perpetuate negative stereotypes!

Individuals described in lay terms as “cross-eyed” have esotropia, one of several forms of strabismus, or misaligned eyes. Esotropia constricts peripheral vision and reduces depth perception (3-D vision), limiting career choices for those who are affected. The psychosocial consequences of strabismus can also be profound. In ancient times, the gaze of a person with strabismus was thought to bring bad fortune (the “evil eye.”) People with strabismus were described as being “shifty-eyed” and untrustworthy (see Chapter 10 in von Noorden’s book). Even today, strabismus causes difficulty gaining promotions at work, trouble finding a suitable partner, and psychosocial stressors including anxiety and depression. Fortunately most people with esotropia - even adults - can be treated with glasses or surgery. Early detection and treatment is key to the best outcomes – which is why we at REBIScan are dedicated to bringing the Pediatric Vision Scanner to market for the detection of even small angles of strabismus in preschool children.

So, Ms. O’Neill, please note that most people who are “cross-eyed” are not “cross-eyed with frustration,” they are frustrated to be cross-eyed, and looking for a way out.

— David G. Hunter, MD, PhD

I am delighted that United Healthcare has updated their policy on vision screening to make it more likely that young children with amblyopia (or amblyopia risk factors) will be referred in time for treatment. (To read the full policy and the research behind it, click here.) In the policy, United Healthcare states that instrument-based vision screening is now proven for children as young as one year of age, meaning that the company will pay primary care doctors to perform vision screening in children. This places United Healthcare’s payment policy in line with the policy endorsing instrument-based vision screening that was jointly released by the American Academy of Pediatrics (AAP), American Academy of Ophthalmology, and American Association for Pediatric Ophthalmology and Strabismus.

I do have a few quibbles with their statement: The policy should be more proactive about assuring that all children receive annual instrument-based vision screening (at least through age 7) even if they appear to be cooperative – in my experience as a practicing pediatric ophthalmologist, I see many children who are able to peek, or memorize letters, or use other tricks to hide the fact that they have a serious vision problem in one eye. These tricks can delay treatment for years.

Also, the policy assumes that “photoscreening” and “instrument-based vision screening” are the same, but of course REBIScan’s Pediatric Vision Scanner (PVS) has been shown to be even more accurate than photoscreening for detecting strabismus and amblyopia when it develops. Photoscreeners refer kids who might have risk factors for amblyopia even though most of them will never develop the condition. Photoscreeners are also not able to detect strabismus, one of the leading causes of amblyopia. The PVS detects both amblyopia and strabismus but does not refer on risk factors alone, which should reduce the number of unneeded referrals. This will save money for the insurance companies while also saving parents the time and trouble of having to take their child in for a dilated eye exam that they don’t need.

All in all, it is great news that United Healthcare, Aetna, and Florida Blue Cross (among others), not to mention the Affordable Care Act, are accepting the AAP recommendations to pay pediatricians for the extra time and trouble required to perform routine vision screening in all preschool children. Let’s encourage all insurance companies, including Cigna, Humana, and others, to recognize that they are placing their young patients at risk for permanent vision loss. Routine, instrument-based vision screening could eliminate preventable vision loss in hundreds of thousands of children, giving high benefit to society at a very low cost.

— David G. Hunter, MD, PhD

Alan Crane, Partner at Polaris Ventures, has talked about how the gap between invention and treatment remains difficult. And medical devices are lagging a bit behind in certain ways, so it’s a story that REBIScan knows very well. If there is to be an improvement in care and a reduction in cost, then there needs to be a more supportive investment ecosystem.

And, yes, there is hope. Groups are changing their attitudes and actions. Boston Children’s Hospital, from which portions of our technology originated, has shifted their Intellectual Property Office into the Technology and Innovation Development Office. This transition is more than just a change of name. It’s a culture pushes inventions out of the lab and into the commercial market.

REBIScan is a beneficiary of this change. In 2009, our technology was a part of the inaugural class of inventions that received TIDO funding to build commercial prototypes and launch the devices into independent clinical trials. The road has been difficult, though rewarding, but had it not been for TIDO, it may not have even been possible.

There is a long road for us to travel, but with every institution supporting health care innovation, the journey will be easier for all — and the better the care will be for those on the receiving end. 

— Justin Shaka

An article in the MIT Technology Review showcased how Kaiser Permanente assess innovation in healthcare by trialing such technologies and ideas at its Garfield Innovation Center. It’s a brilliant concept, and it would be enlightening to see how vision screening stacks up in the Center. The article states that health care operations waste $750 billion per year, which is thirty cents for every dollar spent, but when it comes to current vision screenings we think the waste is even higher.

For illustrative purposes, let’s use our friends in Kentucky as a case study. Kentucky has a lot going for it: Louisville Slugger, the largest gold reserve in the world, and the mandate that every child entering school receive a full eye examination by an eye professional. Each year, approximately 56,000 kids are born in Kentucky, which means that each year approximately 56,000 kids will receive a full eye exam. Let’s assume that the eye professional charges by code 92002, which, according to the American Medical Association, is for new patient eye exams and pays $76 in Kentucky. That’s $4.25 million dollars worth of Fort Knox gold each year for comprehensive eye exams on kids starting school.

It’s a noble effort to provide kids with comprehensive eye exams, but if only 7% of kids are diagnosed with eye conditions, then Kentucky is unnecessarily paying for 52,000 eye exams yearly. The key to reducing costs is to find a more effective way in identifying the 7%. The kids with eye problems need to be found and treated, so those costs don’t go away. Technology needs to be better at identifying those in need of help. We should demand higher quality outcomes, not settle for the lesser of two evils.


— Justin Shaka



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