health week

In Focus: The Vision Problems Facing Gamers

by Jeff Marchiafava on Apr 05, 2011 at 10:50 AM

No matter what games you play or what platforms you play them on, you have probably suffered from the effects of eyestrain at one point or another. Thanks to the recent release of the Nintendo 3DS and the rising popularity of 3D televisions, more concern is being paid to eye health and the potential side effects. Is the media being overly cautious? Can your favorite hobby be detrimental to your vision?

 To answer these questions, we spoke with Dr. Martin Banks, a professor of Vision Science at UC Berkeley who has studied the effect that stereoscopic 3D displays have on human depth perception. In addition to explaining the problems with stereo 3D displays, Banks outlined some other potential eye-related complications facing gamers, and what they can do to avoid them.

What's Wrong With Stereo 3D?
Over the past few years, the film and video game industries have heralded stereo 3D displays as the future of entertainment. By presenting offset images independently to each eye, the brain can be tricked into seeing three-dimensional depth on a two-dimensional display. However, it's not just your brain that's being tricked; stereo 3D displays also trick your eyes, creating a vergence-accommodation conflict that causes the eyestrain most commonly associated with the 3D illusion.

"Vergence is the rotation of the eyes in opposite directions," Banks says. "You converge your eyes to look at something close, and diverge to look at something far. Accommodation is the focusing response of the eyes. The lens inside the eye changes shape to bring an image to sharp focus on the retina.

"In the real world, the vergence distance and accommodation distance are the same because we look at and focus on the same object. With stereo 3D displays, the two distances are often different. For example, when the stereo content is in front of the screen, the eyes converge in front of the screen, but they focus at the screen because that's where the light comes from. Vergence and accommodation are normally coupled, so the viewer now has to work against that natural coupling and this causes some discomfort."

The greater the simulated field of depth, the worse the vergence-accommodation conflict becomes, which is why some stereo 3D movies and games may be enjoyable, while others leave you with a splitting headache. The Nintendo 3DS comes with a slider that controls the intensity of its stereo 3D effects, allowing players to choose a field of depth that's comfortable for them. Unfortunately, not all 3D media has that luxury built in.

Is Stereo 3D Worse For Gamers?
Although stereoscopic images have been around since the 1800s, the newest advances in technology have resulted in stereo 3D media that's far crisper than what previous techniques were capable of. Not only does this new generation of stereo 3D entertainment look better, Banks wagers it's easier on the eyes as well because it's easier for the brain to fuse the offset images.

However, Banks tells us that stereo 3D games may cause more discomfort than movies for two reasons. The first problem is the distance to the screen. "We know that there are things one can do to reduce the discomfort due to the VA conflict. Keep the stereo content near the screen. Keep the viewing distance relatively long." For most gamers, the distance to their television usually depends on the size of their room, and no gaming setup can compete with the distance a movie theater can afford the viewer.

The second problem is time commitment. The longer you spend looking at stereo 3D images, the more likely it is that the VA conflict can cause eyestrain. Moviegoers will hardly ever spend more than a few hours in 3D glasses, which would barely be considered a warm-up session for core gamers. The glasses-free experience provided by the 3DS isn't different from the PlayStation 3's 3D in this case; Banks sees no difference between the systems' 3D displays, because the VA conflict is still present.

So How Bad Is It?
Despite the recent warnings and concerns that have been raised over the Nintendo 3DS, Banks believes that the negative side effects of stereo 3D gaming aren't as bad as some people make them out to be. "...The most likely problem is discomfort (eye strain, headache, fatigue, blurry vision). It seems much less likely to me that long-term effects could occur...There are temporary effects that seem likely. But no permanent ones that seem likely or even plausible. There are some silly claims made about adverse effects that don't make sense."

Banks also told us that when it comes to the warnings directed toward children, the industry is taking a "better safe than sorry" stance. "We don't have evidence that shows that children are in fact more susceptible to some unknown health effect [caused by stereo 3D]."

So, that's the good news. Whatever negative effects you may feel from stereo 3D gaming, they will go away when you turn off the system. However, discomfort caused by stereo 3D is only one type of vision problem that gamers face.

Even Bigger Problems
Despite his experience studying the effects of stereo 3D displays and human depth perception, Banks seemed more concerned with another eye-related ailment, which has the potential to affect many more gamers. "There is [another] concern and that's called near-work myopia. There's pretty good evidence now that children who do a lot of near work (reading, video games) are more likely to develop myopia than children who do less. And that will be the same for stereo 3D vs. conventional [displays]."

Myopia is the medial term for nearsightedness, where objects close to the viewer appear in focus and distant objects appear blurry. Near-work myopia is a temporary form of the condition caused by focusing on a nearby object for an extended period of time. However, some doctors believe near-work myopia can lead to permanent myopia.

Another ailment Banks didn't touch on is keratoconjunctivitis sicca, also known as dry eye syndrome. As the layman's name suggests, dry eye syndrome is a condition where your eyes don't create enough tears, and it's caused by a lack of blinking, as well as environmental conditions. Although dry eye syndrome can be serious, most cases are restricted to temporary discomfort as well.

What Can Gamers Do To Keep Their Eyes Healthy?
When it comes to eye health, the best thing a gamer can do is practice common sense. All of the issues discussed in this article can be alleviated by a few simple steps. Sit as far away from your display as you can, whether you're viewing a stereo 3D or regular display. Take frequent breaks - and that doesn't mean pausing your game to check Twitter on your phone. Walk  away from your television/PC/handheld and give your eyes a chance to focus on something in the distance. If your eyes feel dry, don't rub them (that only makes it worse) - instead blink more and use eye drops to keep them wet. If you're a parent, monitor your children to make sure they don't play for too long at a time and that they aren't experiencing vision problems or pain. Above all else, if you're feeling any type of discomfort, it's time to turn off the game.

In case you missed it, check out Monday's Health Week article on sleep deprivation, and Wednesday's article on carpal tunnel, and Thursday's article on dietary concerns. Remember to also come back every day this week for new stories spotlighting health issues in gaming.