Researchers found tests by trained volunteers correctly caught a similar proportion of toddlers and older preschoolers with the early signs of lazy eye - also known as amblyopia - who were then referred to an ophthalmologist for treatment.
"Finding it early is generally believed to be better," she told Reuters Health.
However, not all researchers and policymakers agree screening very young kids for vision problems is definitely worthwhile.
The U.S. Preventive Services Task Force, a government-backed panel, recommended in 2011 that kids age three to five be screened at least once for lazy eye.
But for babies and toddlers under three years old, the panel said there wasn't enough evidence to weigh the possible benefits and harms of vision screening.
Dr. Michael LeFevre, co-vice chair of the USPSTF and a family doctor at the University of Missouri School of Medicine in Columbia, said the new study doesn't change that.
"The principal research gap really related to after one identifies abnormalities, whether treatment affects the development of amblyopia," LeFevre, who wasn't involved in the new research, told Reuters Health.
"We had evidence that treatment in the three- to five-year age range prevents long term vision loss, but we didn't have any evidence in the younger age range."
A PATCH AT TWO?
Treatment for lazy eye - when one eye loses the ability to see details - usually involves covering up the good eye or making it blurry with drops so the child is forced to use the bad eye instead. Sometimes, children with amblyopia also need glasses to improve their vision.
"You can imagine taking your two-year-old and having them run around with a patch on their eye, how easy it is," LeFevre said. "It's hard enough at age three to five."
For the new study, Longmuir and her colleagues analyzed the records of more than 200,000 Iowa preschoolers who were screened for signs of lazy eye between 2000 and 2011. One-fifth of those kids were younger than three years at the time of testing.
Among babies less than one year old, a quarter of screening tests were unreadable, the researchers found. But when they compared one- and two-year-olds only with the older preschoolers, there was no difference in screening accuracy, according to findings published Monday in Pediatrics.
Between three and five percent of kids were referred to an ophthalmologist for further testing and treatment, based on the free screening.
Doctors confirmed that as many as 90 percent of those positive screeners needed treatment.
Some states offer free vision screening for toddlers, but the idea of eye checks in that age group is "a very debatable topic" given the resources involved, according to Longmuir.
Still, she and her colleagues said parents should take advantage of those programs where they exist - even if their child is younger than three years old.
"If the opportunity exists, go ahead and do it," Longmuir said.
SOURCE: http://bit.ly/X5dOFk Pediatrics, online February 11, 2013.