Reuters Health - Children should get their vision tested at least once between ages 3 and 5, but there isn’t enough evidence to say for sure whether they need evaluations when they’re younger, according to new guidelines from U.S. physicians.

For kids around preschool age, vision screening can help identify risk factors or symptoms of what’s known as amblyopia, or lazy eye, which can lead to permanent vision loss, according to the guidelines issued by the government-backed U.S. Preventive Services Task Force (USPSTF).

“Vision screening of children ages three to five in the primary care practice setting can detect amblyopia, also known as lazy eye, or other conditions that if untreated could lead to amblyopia,” said task force member Dr. Alex Kemper of Nationwide Children’s Hospital in Columbus, Ohio.

“Scientific evidence shows that this can lead to better vision,” Kemper said by email. “For children younger than three, more information is needed about the accuracy of vision screening tests in the primary care setting and the effectiveness of detecting problems in younger children compared to those who are three or older.”

Lazy eye, one of the most common vision problems in children, involves an alteration in the visual neural pathway in a child’s developing brain that can lead to permanent vision loss in the affected eye.

About 1 percent to 6 percent of children under age 6 have amblyopia or risk factors for it, such as eyes that point in different directions or unequal focusing abilities in each eye, the task force notes in guidelines published in JAMA.

Early detection of risk factors for lazy eye can lead to improvements in the ability to focus, the guidelines note.

Treatment is more effective at younger ages, and untreated lazy eye can lead to lasting physical or psychological difficulties, accidents and injuries, poor visual motor skills, and problems with school and work. Treatment can include glasses, often paired with an eye patch.

One challenge in testing children under 3 is that these kids may not be able to reliably articulate what they see during exams, said Dr. William Good, a scientist at the Smith-Kettlewell Eye Research Institute in San Francisco whose editorial on the study was published in JAMA Pediatrics.

“Children older than 3 usually can offer verbal responses to questions about what they see,” Good said by email. “Under 3 years we often can’t rely on feedback from children, a roadblock to learning whether interventions matter for this younger age group.”

The current guidelines apply only to screening of children without symptoms of vision issues.

Even before age 3, kids should have a vision exam if they appear to have issues such as squinting at objects in the distance or consistently closing one eye when they look at things, doctors say. Parents should also tell pediatricians if there’s a family history of vision problems at a young age.

Currently, only about half of kids who should get vision screening are receiving these exams, said Dr. Sean Donahue, author of an editorial in JAMA Ophthalmology and head of pediatric ophthalmology at Vanderbilt University Medical Center in Nashville, Tennessee.

“Vision screening is important to detect problems that cause amblyopia, which is when an eye gets shut off by the brain, usually because it is misaligned or because of an asymmetric need for glasses between the eyes,” Donahue said by email. “New technologies have allowed earlier detection of these problems, prior to when a child is able to read the eye chart.”

SOURCES:

bit.ly/2xP8a4i JAMA, online September 5, 2017.

bit.ly/2xPmVUL JAMA Pediatrics, online September 5, 2017.

bit.ly/2eM8WL0 JAMA Ophthalmology, online September 5, 2017.