Teens have been known to play video games until they're glassy-eyed.
As 3-D television sets arrive in stores -- offering both TV shows and video games in 3-D -- some are concerned that too much eye-popping action could cause headaches, eye strain or worse.
A health warning in April from Samsung, one of the first on the market with 3-D TVs, makes watching 3-D sound like mortal combat.
The TV maker warns that 3-D could cause lightheadedness, nausea, dizziness, twitching or even convulsions, especially in epileptics. Samsung cautions parents to supervise children closely, because they could be more susceptible than adults.
Samsung further advises consumers to take frequent breaks and avoid watching 3-D movies or games when they're "in bad physical condition, need sleep or have been drinking alcohol." The company goes so far as to warn customers not to place a 3-D television near open stairwells, balconies or "other objects that may cause you to injure yourself" if you fall.
But is 3-D really bad for your health?
Because modern 3-D technology is so new, there isn't much research to show it causes health problems, says Gail Summers, a pediatric ophthalmologist at the University of Minnesota.
About 20 percent of people have mild vision problems that could predispose them to 3-D-related headaches or eye strain, says Steven Nusinowitz, an associate professor of ophthalmology at the University of California at Los Angeles. Such problems can include a lack of depth perception or vision that's significantly weaker in one eye.
3-D also can give some people motion sickness. That happens when a person's eyes tell his brain that he's moving even though he's sitting still, Nusinowitz says.
Yet Los Angeles ophthalmologist James Salz says he doesn't expect most people to have any problems. Though eye strain can cause headaches, it doesn't permanently damage the eye, says Salz, a spokesman for the American Academy of Ophthalmology.
Summers, who is president of the American Association for Pediatric Ophthalmology and Strabismus, says parents should watch for health effects in children using 3-D technology, because they may not be able to describe exactly why they feel ill.
"They won't say, 'I have eye strain because I've watched this for too long,' " Summer says. "And older kids may not want to say they have a headache because they don't want their video games restricted."
Explore further: What if our children are the screen-obsessed couch potatoes of the future?