A new handheld scanning device identifies ambylopia (commonly known as lazy eye) at an early stage, when it can still be treated effectively.

Developed by researchers at Children’s Hospital Boston (CHB; MA, USA), the Pediatric Vision Scanner incorporates a low-power laser used to scan the child’s eyes and measure their alignment. The researchers conducted a clinical testing of a prototype of the device in 154 patients at the CHB ophthalmology clinic and in 48 children with normal vision, aged 2 to 18. Children with readily identifiable strabismus, other eye disease, or developmental delay were excluded. As the children look at a blinking red light, a low-power laser scans their eyes to measure their alignment (binocularity), taking five readings over 2.5 seconds.

A binocularity score below 60% (fewer than three focusing successes in five attempts) indicated a need for further examination. Among two- to six-year-old children, binocularity scores averaged 9% for those with amblyopia and 8% for those with strabismus, versus 89% in the control group. The scanner could detect amblyopia even in the absence of measurable strabismus, and documented improved binocularity in these children after treatment. In all, the device demonstrated an impressive 96% sensitivity and specificity for detecting amblyopia or strabismus, compared to gold standard ophthalmologic tests. The study was published in the July 7, 2011, issue of Investigative Ophthalmology and Visual Science.

“The eyes of a child with amblyopia can look perfectly fine, even while one eye is slowly losing vision,” said senior author David Hunter, MD, chief of ophthalmology at CHB. “Once a child reaches school age, treatment is less likely to restore useful vision. We’d really like to begin treating them when they’re three years old – or younger.”

Amblyopia usually results from a misalignment of the eyes (strabismus) or one eye having a weaker focusing power (anisometropia). In both cases, one eye is underused, and vision deteriorates as the brain loses its ability to interpret visual information from that eye. If the problem is detected early, ideally before age four or five, doctors can reverse it by patching the stronger eye or blurring it with eyedrops, forcing the child to use the weaker eye.

Guangzhou Jia Yu medical equipment Limited