Nintendo Warns Parents Of Eye Risks In 3-D Game

Enlarge this image toggle caption Shuji Kajiyama/AP Shuji Kajiyama/AP

Three-D effects are everywhere -- in movies, on television and in video games. But now Nintendo, which is releasing a 3-D, hand-held gaming console called the Nintendo 3DS, will be putting a health warning label on the new device.

Other 3-D media manufacturers have issued similar warnings because there's a risk that using a display so close to the eyes could cause eye fatigue and headache.

Nintendo's website says the 3-D effects in its new game could cause vision problems in children under the age of 6, and some vision scientists agree.

Forming The 3-D View

A three-dimensional effect is created on a flat screen like a video game device or television by filming a scene with two cameras.

"Each camera gets a slightly different view, and that creates what's called binocular disparity," says Ahna Girshick, a vision researcher at New York University. Binocular disparity is what you get when you look at the world with two eyes. Each eye sends an image to the brain that sees the world from a slightly different angle.

"The brain is accustomed to processing that. And it creates this 3-D impression," she says. Makers of 3-D media are taking advantage of that. "So they're just piggybacking what's already built into our eyes and brains."

Artificial Conflict In The Brain

But there's a problem: We also get some information about how far away an object is by how much we adjust the lens in our eyeball to bring it into focus.

"So with a near display, like if you're looking at a TV and you are sitting up close, your eyes actually focus on the surface of the TV, and that's at one distance," Girshick explains. But if the TV is showing a 3-D image, your brain might think an object is far off in the distance, even though your focus is on the screen right in front of you.

"And these two systems are now in conflict. In the natural world they're never in conflict," she says.

It's this artificial conflict that's causing some concern about children using 3-D video games. Vision scientist David Hoffman, who works at the semiconductor company Mediatek, says children's visual systems are changing as they grow.

"Any time you've introduced something from what they're normally exposed to, there's a chance that they begin to adapt to whatever this new condition is," Hoffman says. That new condition would be unnatural and could possibly not be good for the children when they weren't playing video games.

There aren't a lot of good data about just how much long-term damage these games could cause. They may cause no damage at all. But some game manufacturers have decided to err on the side of caution and recommend that young children not use the 3-D mode. Enforcing that recommendation, though, falls to the parents.