Vision screening in children

December 31, 2012

A review of new automated screening technologies to help detect vision problems in young children.

As we strive to see more patients while continuing to provide quality care, pediatricians are learning new ways to improve and invigorate their practices. Innovation can provide more accurate office diagnostics and new treatment alternatives while promoting staff efficiency and patient satisfaction. As a start to this ongoing series looking at ways to move pediatric practice to the "next level" (Pediatrics v2.0), we'll review new recommendations that encourage pediatricians to use automated screeningh technologies (ie, photoscreeners) to detect vision problems in young children.

The importance of vision screening

Amblyopia is one of the most common visual problems of childhood, occurring in as many as 1% to 4% of children.1 It is defined as poor vision caused by abnormal development of visual areas of the brain; if undetected and untreated it can lead to permanent vision impairment.

Unfortunately, less than 21% of children are screened for this condition.2 Causes of amblyopia include strabismus (misalignment of eyes), anisometropia (inequality of vision of both eyes because of refractive errors or astigmatism), cataracts, ptosis, or other factors. Because children do not complain of problems with visual acuity, and affected eyes often appear normal, amblyopia can easily go undetected unless a child has vision screening done routinely at health maintenance examinations.

Vision screening in children aged younger than 3 years in a medical office can be challenging because few children this age can be screened with a vision chart. From age 3 to 5 years, screening is possible with Snellen charts, Tumbling E charts, or picture tests such as Allen Visual Acuity Cards, but this is time consuming and can lead to inconsistent or erroneous results.

Because vision screening is so important in young children, late last year the Section on Ophthalmology and Committee on Practice and Ambulatory Medicine of the American Academy of Pediatrics (AAP) issued a policy statement endorsing instrument-based vision screening (ie, photoscreeners) routinely in childhood.3 This policy was endorsed by the American Academy of Ophthalmology, the American Association for Pediatric Ophthalmology and Strabismus, and the American Association of Certified Orthoptists. The policy recommends that photoscreening may be electively performed in children aged 6 months to 3 years to facilitate detection of conditions that may lead to amblyopia and that this technology be used as an alternative to visual acuity screening with vision charts for children aged from 3 to 5 years.

Not always so

Ten years earlier in 2002, the AAP issued a lukewarm endorsement of photoscreening, describing these devices as “an innovative tool that can facilitate vision screening in children” and “one option to increase the screening rate in preschool-aged children.”4 As a consequence, most insurance companies considered photoscreeners as experimental and refused to pay for vision screening using this technology.

In 2004 and again in 2011, the US Preventive Services Task Force, an independent group of national experts, also endorsed the use of photoscreeners to detect vision problems in children aged 3 years and older.5 Insurance companies also ignored this endorsement when pediatricians challenged rejected claims. Without insurance reimbursement, few pediatricians adopted these expensive devices, and parents were often reluctant to pay for screening out of pocket.

In the decade interval between the first and second AAP policy statements, photoscreening technologies have evolved and have been scrutinized in many well-designed studies. Now there is compelling evidence that supports their routine use in pediatric practice.

In the Vision in Preschoolers Study, published in 2004, it was found that visual acuity testing (using eye charts) in more than 2,500 preschool children had a 77% sensitivity for detecting conditions associated with amblyopia, and photoscreener devices had a sensitivity of 81% to 88%.6 Note that the use of photoscreeners not only improves detection of eye pathology but also does so in a fraction of the time required to perform testing with eye charts. The AAP points out that the referral criteria integrated into these devices balances detection of vision problems against overreferrals.3

Additional studies have looked at the effect of early detection and treatment of amblyopia on visual acuity. With mild disease, treatment with patching or glasses has been shown to improve visual acuity significantly after 2 to 12 months of treatment. For those with more severe disease, treatment has been shown to improve visual acuity as much as 1 to 2 lines on the Snellen eye chart.5

Photoscreening devices

Pediatricians interested in incorporating photoscreening technology into routine practice have a number of devices from which to choose. To start your program, you need to purchase a photoscreener, train support staff and providers to use the device, and become familiar with the reports that the devices generate.

Perhaps the most important component of an office-based vision screening program is establishing a relationship with your local pediatric ophthalmologist, who can help program the device with the assistance of the manufacturer to optimize referral rates (avoiding overreferrals while maximizing detection of treatable problems).

The German company PlusoptiX is introducing its fourth-generation vision screener this year, the portable PlusoptiX model S12. The child sits comfortably in his or her parent’s lap, and the device is positioned 1 meter away. Patient information is input with a touch screen interface, and pulling a trigger button then activates the camera. The device produces a warbling sound to attract the child’s attention and gaze toward the smiling face displayed on the patient side of the PlusoptiX device. The operator’s side of the device displays a video image of the patient. The eyes are positioned in a white rectangle on the viewing screen, and the device performs its measurements automatically, in less than a second.

In this time interval, 36 pictures of both eyes are recorded, and measurements regarding pupil sizes, corneal reflexes, and refraction are displayed on the screen, as well as an indication of whether the child passed the screening. The device records the patient data on a secure digital card that can be transferred to a computer to print the result for incorporation into the patient record. According to PlusoptiX, the device can detect amblyopia with a sensitivity as high as 92% and specificity as high as 88%. The PlusoptiX S12 is expected to sell for $5,875. Reimbursement (when insurers do reimburse) is approximately $25 to $35 per screen.

PediaVision was once an American distributor of the PlusoptiX device, but a few years ago the company developed a photoscreener called the Spot Vision Screener. Physicians familiar with digital cameras find the screener easy to use. After inputting identifying information, one aims the device toward the child, and the child’s face is positioned on a display. The device indicates whether you are too close or too far from the patient and then initiates the screening sequence, which is completed in less than a second. The screen displays the pupillary size, distance, alignment, and complete refraction information for both eyes and indicates whether the child needs to be referred to a pediatric ophthalmologist. Additionally, the device can connect to a wireless network to facilitate printing a complete report for inclusion in the record. The Spot Vision Screener sells for $7,490.

The iScreen Vision Screener is yet another photoscreener that takes pictures of the pupillary and red reflex to screen for amblyopia. In contrast to the automatic computer analysis of the photos of the red reflex performed by the PlusoptiX and PediaVision devices, the iScreen Vision Screener is connected by a network cable to your office network and transfers each patient screening test to a “professional” who interprets the test (with computer assistance) and provides information regarding whether the patient is at risk for amblyopia and should be seen by a pediatric ophthalmologist.

The iScreen device sells for $4,000, and each test costs $8. The manufacturer states that having an experienced professional interpreting its photoscreening results improves the accuracy of the test. Because reports are transmitted to the patient’s provider the day after the test, parents must be informed via phone or letter with results.

Coming soon: Retinal birefringence scanning

The photoscreeners described above use analysis of the pupillary and red reflex to screen for amblyopia. As noted, screening is faster and often more accurate with photoscreeners compared with traditional screening using vision charts, particularly with children aged younger than 5 years. If there were a limitation to photoscreeners, it is that there is an overreferral rate on the order of 10% associated with these devices. Hence, it is important that screening is performed yearly at well-child checks, and when a child is referred to an ophthalmologist, parents should be reminded that there is a possibility that no pathology will be discovered.

David Hunter, MD, chief of ophthalmology at Boston Children’s Hospital, has a new technique of screening young children for amblyopia using a device he developed and refined over the past 20 years. The device, called the Pediatric Vision Scanner (PVS), uses polarized laser light to test eye orientation at the retinal level.

The PVS laser light scans the fovea at the center of the retina, which has the highest concentration of cone receptors. The polarized light passes through the nerve fibers surrounding the fovea and is reflected back toward the device sensors. This causes the strength of the returning light to change during a scan, indicating whether the eyes are in perfect alignment.

The technology is called retinal birefringence scanning, and Hunter has formed a company called REBIScan to commercialize its use. The US Food and Drug Administration is currently evaluating the PVS and if given approval for distribution the device may be available for use by pediatricians as early as the second quarter of this year.

Data from several well-designed studies indicate that the PVS has a superior detection rate for amblyopia (96% sensitivity) and minimizes overreferrals because the specificity is very close to 100%.7,8 Therefore, when the device identifies a child as needing referral, it is likely that the pediatric ophthalmologist who examines the child will discover a condition requiring treatment rather than monitoring or yearly rescreening.

The PVS device looks somewhat like a projector used to give PowerPoint presentations. While the child sits comfortably in the parent’s lap, the PVS is aimed at the bridge of the nose, which is the target for the laser light emitted by the device. Once targeted, the device is activated, and seconds later, 2 lights atop the unit indicate a pass or refer result, while a small liquid crystal display indicates details of the test. As of this writing the cost of the device has not yet been determined.

The battle begins

As noted earlier, insurance companies have traditionally not reimbursed for photoscreening tests, stating that the technology is “investigational,” and consequently most pediatricians have not invested in this expensive technology. Photoscreening companies have encouraged pediatricians to have parents sign an insurance waiver permitting practices to perform the screen-and parents are charged a fee of $25 for the test. Many pediatricians have told me that parents are very disappointed when they pay out of pocket for the test and are referred to their ophthalmologist only to be told there is nothing wrong (there was a false-positive screen).

The new statement from the AAP endorsing photoscreeners gives pediatricians the leverage they need to encourage insurance companies to reimburse for the testing. The policy states: “Vision screening is a separately identifiable service and should not be bundled into the global code of well-child care. Adequate payment for photoscreening and handheld autorefraction must be ensured if there is to be widespread adoption of this recommendation.”3

The Affordable Care Act assures that vision screening for children is a preventive care measure that will be implemented across the country by 2014, although it does not currently provide details regarding methods of screening.

Pediatricians wishing to implement photoscreening must be willing to confront insurance companies with the assistance of the local AAP chapter, the state insurance commission, and even state government.

To advance pediatric practice to v2.0, we must be willing to aggressively advocate for the families we serve. Only by implementing vision screening in our younger patients can we hope to identify children with amblyopia that would benefit from early treatment.

References

  • Simons K. Amblyopia characterization, treatment, and prophylaxis. Surv Ophthalmol. 2005;50(2):123-166.

  • Ehrlich MI, Reinecke RD, Simons K. Preschool vision screening for amblyopia and strabismus. Programs, methods, guidelines, 1983. Surv Ophthalmol. 1983;28(3):145-163.

  • American Academy of Pediatrics, Section on Ophthalmology and Committee on Practice and Ambulatory Medicine; American Academy of Ophthalmology; American Association for Pediatric Ophthalmology and Strabismus; American Association of Certified Orthoptists. Instrument-based pediatric vision screening policy statement. Pediatrics. 2012;130(5):983-986.

  • Committee on Practice and Ambulatory Medicine and Section on Ophthalmology; American Academy of Pediatrics. Use of photoscreening for children’s vision screening. Pediatrics. 2002;109(3):524-525.

  • US Preventive Services Task Force. Vision screening for children 1 to 5 years of age: US Preventive Services Task Force recommendation statement. Pediatrics. 2011;127(2):340-346.

  • Schmidt P, Maguire M, Dobson V, et al; Vision in Preschoolers Study Group. Comparison of preschool vision screening tests as administered by licensed eye care professionals in the Vision in Preschoolers Study. Ophthalmology. 2004;111(4):637-650.

  • Loudon SE, Rook CA, Nassif DS, Piskun NV, Hunter DG. Rapid, high-accuracy detection of strabismus and amblyopia using the pediatric vision scanner. Invest Ophthalmol Vis Sci. 2011;52(8):5043-5048.

  • Nassif DS, Piskun NV, Hunter DG. The Pediatric Vision Screener III: detection of strabismus in children. Arch Ophthalmol. 2006:124(4):509-513.