The parents of 9-year-old Kurt Hess limit their son's time in front of the computer.
Instead, his mother, Tania, urges him to play outside.
"I play video games on the weekend or Friday," said Kurt, a fourth-grader in Illinois.
But, as winter weather keeps more kids like Kurt cooped up indoors, many turn to computer games and Web surfing for fun. This not only limits the amount of physical exercise they get, there is some evidence it also may be hurting their vision.
Kids who spend a lot of time on the computer may be at risk of developing eye strain and even "computer vision syndrome," although the seriousness of the second condition is under debate.
Some well-known signs of eye strain include headaches, constant rubbing of the eyes, dry eyes and fuzzy vision. These symptoms usually go away once a child or adult takes a break from the computer.
But optometrist Cary Herzberg said people often struggle to focus on computer monitors, and this may lead to more serious problems.
"When you look at a lighted screen, the eye doesn't focus on the screen, it focuses behind it, so the eye has to adjust all the time to see well," Herzberg said.
Herzberg said this could possibly lead to permanent damage in children in the form of premature nearsightedness, also know as myopia.
"I'm seeing it in younger ages, and I'm seeing much higher prescriptions at younger ages," he said. "It's an interesting phenomenon."
Herzberg participated in a study several years ago that suggested one in four children may suffer from eye strain serious enough that an eye exam would be recommended.
However, the research was sponsored by a company that makes an FDA-approved device designed to test eyes for computer strain.
If strain is detected, Herzberg said specialized glasses can then be prescribed to reduce eye fatigue. The glasses cost about the same as most prescription eyeglasses.
Pediatric ophthalmologist Benjamin Ticho is skeptical. He said he sees no need for special glasses, but he does advise medical students training under him at University of Illinois Medical Center at Chicago to be mindful of computer strain.
"There isn't good research that says it causes permanent damage, but even temporary symptoms are worth noting," said Ticho.
For parents and others concerned about eye strain, experts recommend the following:
Make sure the computer workspace fits smaller bodies.
The screen should be tilted slightly downward at a 15-degree angle.
The distance between the monitor and the child should be about two feet.
Limit computer and game use to 20 minutes at a time.
Make sure children receive annual eye exams beginning before kindergarten and thereafter.
WLS-TV in Chicago prepared this report.