In the News
Amblyopia (“lazy eye”) and strabismus (misaligned eyes) are medical eye conditions that combine as the leading causes of preventable monocular vision loss in children. Care providers are frustrated because amblyopia and strabismus can be difficult to detect, and as a result half of children with the disease are not identified until school age, while up to 40% of referrals to eye care specialists may be unnecessary. Amblyopia is fully treatable if caught early, yet because of the difficulty detecting the condition, hundreds of thousands of children in the United States—and millions worldwide—suffer permanent vision loss every year. REBIScan, Inc. has developed a solution to this problem: the Pediatric Vision Scanner (PVS). This portable device uses a new technology—retinal birefringence scanning, which was co-invented by the company’s founder, Dr. David Hunter—to detect amblyopia and strabismus when they develop. Medical assistants in the pediatric office may operate the device to perform annual vision scans. The Pediatric Vision Scanner will reduce false referrals to ophthalmologists while improving detection of disease and bringing children to care earlier, thereby eliminating vision loss from amblyopia.
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 disturbs normal interpersonal interactions, resulting in poor self-esteem, social anxiety, and phobias. Strabismus, amblyopia, and loss of binocular vision also limit employment options leading to productivity loss in the population.
The combined cost of amblyopia screening (using current technology) and strabismus surgery in the US is estimated to be $800 million annually, while the cost to society from loss of function is estimated at well over $20 billion. Correction of strabismus improves quality-adjusted life year (QALY) scores significantly, and patching for amblyopia and surgery for strabismus are considered cost-effective intervention ($1,632/QALY for strabismus and $2281 for amblyopia).
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. The PVS annual scanning program aims to shift the curve of care delivery to a preventative stage where disease is manageable, affordable, and correctable.
Primary care physicians have struggled to consistently detect and diagnose strabismus and amblyopia because often the signs cannot be detected by a competent pediatrician. These physicians are vulnerable to medical malpractice if they fail to detect eye conditions, but they consume excess health care resources if they they refer children with normal vision to a specialist. The state of the art today for most of the 166,000 primary care providers in the United States is the same visual acuity testing in the office that was used in the 1950s: A child places a cover over one eye and reads the letters or symbols on a chart with the other. 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 and causes more psychosocial problems. Even at age 5 and above, the results of visual acuity testing are often inaccurate. Automated refraction or photoscreening devices have been developed to try to improve upon visual acuity testing, 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 refractive criteria for photoscreening referral, but at least one study suggests that only 1 of 8 children with AAPOS vision screening referral criteria goes on to develop amblyopia. In REBIScan’s interviews with physicians, it is clear that there is an urgent need for a quick, safe, and effective method of screening children for eye conditions.
The Pediatric Vision Scanner (PVS) is a device that in a quick 2.5-second scan of the eyes can automatically detect strabismus, amblyopia, and other serious eye conditions in children as young as 2 years of age. The PVS is the result of 20 years of repeated cycles of design, construction, testing, and revision (see Research). The initial work, performed at Johns Hopkins, showed that it is possible to detect the fixation of a human eye automatically and remotely (from >1 m away) by scanning the eye with a circular beam of low-intensity, polarized laser light. This technology was patented by Johns Hopkins. A binocular scanner was then developed, tested, and revised at Johns Hopkins and in collaboration with the Space Telescope Science Institute. The PVS was tested in the ophthalmology clinic in a 5-year clinical trial conducted at Children’s Hospital Boston and Harvard Medical School. That study showed that 97.3% of children who were given a “pass” result by PVS had normal eyes, while essentially 100% of children who received a “refer” result had amblyopia, strabismus, or vision loss requiring medical attention (see PVS Reanalysis). These studies showed that it was possible to detect all types of amblyopia with retinal birefringence technology – a concept that was patented by Children’s Hospital.
On the basis of these impressive clinical trial results, REBIScan was formed to develop the technology and make it available to pediatricians using a sustainable business model. After working with Children’s Hospital to obtain additional research funding, the company collaborated with Continuum Advanced Systems and obtained an SBIR award to build a more portable and user-friendly device. These new devices, which have been determined to be non-significant risk investigational devices by the Food and Drug Administration, are currently being tested in independent clinical trials.
The clinical advantages of the PVS are its accuracy and simplicity. The device can be operated, and results interpreted, by any staff member in a medical office after a brief training session. The device can also determine when the child looks away from the target during the test, allowing for measurements to continue until a requisite minimum of 5 scans have been obtained. The unit itself is small enough to be used as a hand-held device or table-mounted. This gives flexibility to pediatricians who often lack storage space, and the hand-held design allows the device to be brought to the child seated on a caregiver’s lap. The software gives unambiguous results that indicate whether both eyes were accurately fixating on the target (“pass”) or one or both eyes were not fixating (“refer.”)
Aside from the efficiencies in preventative care and the coordination of follow-up care, our analysis also shows that a program of annual screening with the PVS will reduce eye specialist expenditures by 57% (due to fewer false-referrals), reduce vision plan expenditures by 76% (by lowering the need for lifetime glasses in patients with monocular vision loss), and cut family expenditures by 67% (for co-pays). The PVS will also reduce family expenditures for days off work pursuing care and prevent lost productivity caused by undetected and untreated disease.
At REBIScan we foresee a day in the very near future where all children aged 3–8 will receive a PVS scan during their annual well-child visit. The result will be either a “pass” measurement in nearly all of the children who have no eye problems or a “refer” recommendation in the children who have suffered vision loss from amblyopia, strabismus, or other medical conditions affecting the eyes. Those who are at risk for vision loss will either be referred or rescanned annually until they reach visual maturity. The result will be the early referral of all children with amblyopia and strabismus when it is most amenable to treatment, a reduction in the cost of detecting and treating those children, and the eradication of severe vision loss from the #1 theft of sight in children and adults.