Latest Improvements in Amblyopia Vision Screening Devices

(This article was prepared with the story help of Dr. Catherine M. Croke*)

Vision screening children between 3 and 5 years has been long recommended for the detection of amblyopia. Initially, ophthalmologists relied on eye charts for vision screening. Eye charts are effective for 6 to 7 years old children, at a time treatment of amblyopia begins to be difficult. During the past couple of decades, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) started recommending that elective instrument-based photoscreening, be performed as early as 6 months of age, in the window of 6 months to 3 years. The AAPOS endorsed instrument-based vision screening for patients beginning at age 6 months because waiting to detect amblyopia till the age of six makes it difficult to treat. Moreover, any uncooperativeness from the parents or lack of treatment at this critical age may leave the patient with significant visual impairment that persists throughout life. Detecting amblyopia at an early age is the key to successful treatment. The goal of vision screening at an early age is to detect poor vision or risk factors for amblyopia at a time when a Pediatric Ophthalmologist can initiate an effective therapy.

There are two types of tests to detect amblyopia; the tests for detecting amblyopia and the tests that detect risk factors. The tests for detecting amblyopia include visual acuity tests, fixation and optical tracking tests, Optokinetic Nystagmus reflex, Neutral Density Filter Testing, Visual Evoked Potentials, etc. Those tests are made to detect whether a refractive error, strabismus, or cataracts exist and can cause amblyopia.

Tests that detect amblyopia risk factors include autorefraction and photoscreening that are performed by Pediatric Ophthalmologists or through screening programs run in community centers, schools, general pediatricians, ophthalmologists, etc.

Photoscreeners’ accuracy to identify children at risk for amblyopia was limited by low detection of strabismus and high false-positive rates. The amblyopia risk factors captured by photoscreeners are far more prevalent than amblyopia itself (21% vs. 2.5%). The risk factors photoscreeners rely on to detect amblyopia are not strong predictors of a child actually having amblyopia. Photoscreeners have a false referral rate of 87.5%, which means that 1 in 8 children referred to a pediatric ophthalmologist with risk factors actually end up having amblyopia.

In 2016, the U.S. Food and Drug Administration cleared a new pediatric vision screener named blinq ®. A prototype of Blink, a handheld screening device, was recently employed by a study published in the Journal of the American Association for Pediatric Ophthalmology and Strabismus. The study revealed that the device accurately detects subtle misalignment of the eyes accurately and identifies children with amblyopia (lazy eye),

“The findings suggest that pediatricians and other primary care providers could use the device to catch amblyopia at an early age when it’s easier to treat,” said Michael F. Chiang, M.D., director of the National Eye Institute (NEI), which supported research and development of the device.

By comparing the blinq™ pediatric vision scanner to previously employed screeners, blinq™ has a much lower false-positive rate of less than 15%. 

The blinq™ device is a polarized laser scan that probes the nerve fibers inside the retina. This allows blinq™ to detect small-angle strabismus, which is a subtle misalignment of the eyes’ foveas. Even a small misalignment of the foveas can interfere with the brain’s ability to integrate images from both eyes. Such precision in detecting misalignment of the foveas identifies with 100% accuracy children who have amblyopia, significantly reducing false positives compared with other photoscreeners.

*Dr. Catherine M. Croke, Editorial Board. Dr. Croke has more than 30 years of business experience and currently serves as Sr. Advocacy & Compliance Manager for Evonik, one of the world’s leading specialty chemicals companies.  Dr. Croke holds a DBA from Columbia Southern University, an M.S from St. Joseph’s University, and a B.S. from Philadelphia College of Pharmacy and Science.