Detecting "Lazy Eye" Earlier
BOSTON, July 7, 2011 /PRNewswire-USNewswire/ -- A simple, seconds-long screening exam with a handheld scanning device may enable pediatricians to identify "lazy eye," a loss of vision in a structurally normal eye, in children as young as 2, report ophthalmologists at Children's Hospital Boston, who tested the device in 202 children.
Lazy eye or amblyopia, affecting 3 to 5 percent of all children, is the leading cause of vision loss in childhood. But it can be hard to detect in young children, who are the most responsive to treatment, because they cannot reliably communicate what they're seeing or read eye charts.
"The eyes of a child with amblyopia can look perfectly fine, even while one eye is slowly losing vision," says senior author David Hunter, MD, chief of ophthalmology at Children's Hospital Boston. "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 4 or 5, doctors can reverse it by patching the stronger eye or blurring it with eyedrops, forcing the child to use the weaker eye.
Clinical testing of a prototype of the device, known as the Pediatric Vision Scanner, is described in the July 7 issue of the journal Investigative Ophthalmology and Visual Science. As children look at a blinking red light, a low-power laser scans their eyes to measure their alignment (known as binocularity), taking five readings over 2.5 seconds.
Hunter and colleagues tried out the scanner in 154 patients at Children's ophthalmology clinic and 48 children with normal vision, aged 2 to 18. Children wit