Does your preschooler really need glasses?
Will some young children grow out of early farsighted, or is there reason for concern about their learning ability once they enter school?
That’s the question facing parents whose children may be struggling to see nearby objects. A recent study done at The Ohio State University suggested that moderately farsighted preschoolers and kindergartners performed worse in early literacy than children with normal vision. The study’s authors suggested that since educational demands continue to increase for preschoolers, their vision problems should be corrected.
But sometimes research studies cause more confusion than clarity, said Falmouth Hospital ophthalmologist Jane Schweitzer, MD.
Whether to prescribe glasses to children to correct farsightedness (also called hyperopia) is controversial, she said. Many ophthalmologists argue against prescribing glasses because the issue will resolve itself on its own for many children.
“If the child is mild to moderately farsighted, they will frequently outgrow that,” Dr. Schweitzer said. “There may be no need to burden a child with glasses – because it is a burden to a little kid to hold onto them, take care of them and play sports. And it’s a burden to the parents. They have to change the prescription frequently.”
Dr. Schweitzer said the study does not address cognitive ability as the child matures. She believes it would be a “huge leap of faith” to say that the children could not catch up later on. She also noted that two of the three indications of cognitive ability in the study were based on visual tests.
“Of course they’re not going to do as well,” she said. “They couldn’t take the test as well. It’s almost like IQ tests for people where English is a second language. People who have different cultural backgrounds frequently don’t do well on those tests but it’s a testing artifact, not a true measure of intelligence.”
That said, Dr. Schweitzer believes the study does bring up a related condition that is very important to recognize in children under the age of eight – amblyopia, or lazy eye.
Lazy eye can occur for many reasons, including an uncorrected refractive error, which simply means not wearing the corrective lenses they need.
When one eye doesn’t see well and the other sees just fine, it causes the child’s brain to develop a physiological adaptation. If the brain receives information from the stronger eye and isn’t motivated to use the less clear image to interpret visual stimuli, then the brain may never be able to develop that ability past the age of eight.
“That is medically serious because when these kids show up as young adults, it is actually too late for them,” Dr. Schweitzer said. “I still see a lot of adults with lazy eyes and they ask me what I can do now. The answer is nothing and that is one of the answers that a doctor least wants to give. It’s very frustrating.”
Lazy eye is not always visually obvious, and it can go undetected. Dr. Schweitzer suggests that parents ask their pediatricians about checking for lazy eye, especially if they have a family history of it, since the condition tends to run in families.
The treatment for a refractive lazy eye is a two-pronged approach. First, the child is fitted with glasses that are corrective for the weaker eye and has clear glass for the stronger eye. The stronger eye is covered with a patch for a certain number of hours each day. This forces the eye to see through the corrective lens.
No discussion about children’s eyesight would be complete without including the opposite problem of hyperopia – myopia or nearsightedness. Myopia is one of the most common eyesight problems in the world, and the number of people who have it has gone up dramatically. A 2009 study found that myopia had increased to more than 40 percent of the U.S. population in recent years, up from 25 percent in the early 1970s.
Dr. Schweitzer said she is encouraged by recent studies that offer a healthy way to prevent myopia. Children who spend more time outdoors playing are less likely to develop nearsightedness and need glasses. One study showed that for each additional hour children spend outdoors per week, their risk of being nearsighted dropped by about 2 percent. Studies in Taiwan and Denmark support the theory that exposing young eyes to natural light is good for them.
Another three-year study of 1,900 first graders in China assigned half of the children to an extra session of outdoor recess. About 40 percent of the children who did not get the extra recess had developed myopia, compared to almost 30 percent of the children who spent more time outdoors.
There are many studies that have examined risk factors for becoming nearsighted, but this study was particularly interesting because it hypothesized that the more a person uses his or her eyes for close vision, the more the eyes become habituated for near vision, said Dr. Schweitzer.
“The idea is you should spend more time using your distance vision, which evolutionarily is the natural position. When the hunter-gatherer lifestyle was dominant, man had to be able to see a bear 50 feet away. You didn’t necessarily need to read the hieroglyphics on the cave wall. Now we live in a civilization that requires near vision activity for success.”