Optometrists at eight centers across the country analyzed 253 children, questioning them about computer habits and eye fatigue symptoms -- headaches, eye soreness, and blurry vision. They also checked the kids' eyes with various visual acuity and focusing tests.
"We found that 25-30% of the kids we tested were at risk for computer vision problems," says Cary Herzberg, OD, a private practice optometrist in Aurora, Ill.
The study, led by a researcher from the University of California, Berkeley, has not yet been published.
Just like adults, kids get eye fatigue when they stare at a computer too long, Herzberg tells WebMD. "But because kids are so adaptable, they won't complain about it."
Nearsightedness is not always the result of eye fatigue, he says. "But a number of studies have shown that the more close work a child does, the more it leads to nearsightedness."
At the heart of the problem is what vision specialists call "accommodation," Herzberg explains. "When you read a book, your eyes are not constantly looking at the next word in the sentence. They will jump from one part of the sentence to another. Each time your eyes make that jump, they have to refocus, accommodate for the distance. That causes eye fatigue."
With computer work, eyes have to make more extreme changes in focus. "When you look at a screen, you don't focus only on the screen. You focus behind it a lot of the time." The eye fatigue that comes from that constant switch -- from 16 inches away to 20 inches away -- causes what's become known as "computer vision syndrome," says Herzberg.
To prevent eyestrain, the child might need specially coated protective eyewear -- "computer glasses," he tells WebMD.
It's true, eye fatigue is a common problem with computer use, says Evelyn Paysse, MD, assistant professor of ophthalmology and pediatrics at Baylor College of Medicine in Houston. She agreed to comment on Herzberg's study.
But it's the vibration in the cheaper monitors that bothers eyes most, she tells WebMD.
"Look sideways at the image on a cheap monitor, and you can see the vibration. Your eyes are dealing with this little bit of change in the image clarity, going back and forth, without the brain knowing it. That's what causes eye fatigue."
Whether eye fatigue will lead to nearsightedness, "is inconclusive, it's not been confirmed in the ophthalmology literature," Paysse says. "Most of us don't believe that it does."
However, she admits, "when you look at cultures ... where people don't read, there's very little myopia. And in cultures where there is more education, there's more myopia. So there may be some little bit of truth to it, but it's not been proven."
Will special computer glasses help eye fatigue? "I just don't think so," says Paysse. "The problem is an issue of the computer monitor quality. Try and invest in the best quality monitor you can get. A flat-screen monitor is best."
Also, it helps to take a five-minute break every hour to rest your eyes, she says.
- Don't sit too close to the screen. Two feet away is best.
- Sit up straight.
- Make sure the screen is below eye level, so eyes will focus accurately.