Two-dimensional entertainment is so 2009.
With Sony’s release of the 3-D upgrade for PlayStation 3, the upcoming 3-D Nintendo DS, at least two 3-D television channels on the horizon, and the box office success of a little flick called Avatar, the consensus is clear: The future of entertainment is 3-D.
But while moviegoers have flocked to recent 3-D offerings, film fans also have had mixed reviews about their experiences, with some reporting headaches, nausea, vision problems and motion sickness. And with 3-D leaping to the small screen, clinical researchers and tech experts want to know whether the special effect might damage eyes in the process.
“The problem with 3-D displays is that unlike the real world, only a subset of the information that normally informs us about the 3-D structure of the world is present,” said Robert Allison, a computer science associate professor at York University who specializes in 3-D vision and technology.
And processing that incomplete visual information does, in fact, impact our eyes.
Marty Banks, an optometry professor at the University of California at Berkeley, found that 3-D displays cause a certain type of eyestrain he terms “3-D fatigue.”
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Essentially, the eyes and brain see 3-D images projected onto screens differently than the 3-D objects in the natural environment. After a while -- and particularly at close distances to the screen -- that unnatural image processing tuckers out a person's eyes.
Let’s say you look at an apple sitting on a table. Both eyes adjust to center that apple in your retinas in a process called vergence. Next, your lenses focus those apple images perceived by each eye into a single, clear apple, which is referred to as accommodation.
Normally, that vergence-accommodation relationship goes off without a hitch since the eyes converge and accommodate at the same distance from the object.
Not so with 3-D displays.
It's Not Normal
“The problem is the brain has to work against this normal relationship that it’s acquired in the real world, and that’s been shown to cause discomfort and fatigue,” Banks told Discovery News.
When you watch a 3-D movie, vergence and accommodation happen at different distances because the eyes accommodate at the distance to the actual movie screen, whereas vergence occurs where the 3-D imagery is projected, which might be in front of or behind the screen to create depth.
That distance discrepancy results in vergence-accommodation conflict, which is the source of eyestrain.
The good news is Banks doesn’t see this type of temporary eyestrain as a major cause for concern for viewers, especially since the entertainment industry is producing more sophisticated 3-D displays that drastically reduce that vergence-accommodation conflict.
He cited Avatar as a prime example of a 3-D film thoughtfully engineered to literally “drag the viewers’ eyes” to specific points of interest onscreen, which creates a much gentler visual experience.
“They’re putting that object of interest to where most of the time it’s not in front of the screen or behind; it’s right at the screen,” Banks said. “And that makes the vergence-accommodation conflict zero."
Better Technology is Alleviating the Problem
Allison at York University also noted that recent 3-D movies have gotten better at reducing eyestrain by mimicking our natural stereoscopic vision.
“People are becoming less gimmick-oriented in terms of 3-D content,” Allison explained. “There’s more emphasis on a comfortable viewing experience where stereopsis enriches the experience rather than defining it, and recent movies like Avatar or Up! have been very easy on the eyes.”
Three-dimensional television, however, might be harder to watch.
For starters, Banks’ research at Berkeley has also found a correlation between eye fatigue and proximity to a 3-D display. And since people generally sit much closer to televisions than movie screens, it could invite more unpleasant side effects.
Also, 3-D TV viewers will have to be more mindful of their couch potato posturing.
“A lot of the people like to watch TV lying on the couch… and that’s just not going to work,” Banks said.
Tilting your head perpendicular to a 3-D display would aggravate the vergence-accommodation conflict by not only forcing your eyes to unnaturally shift horizontally but also causing them to converge vertically, in the direction your eyes are pointing, he explained.
But as technology continues to improve, 3-D television isn’t doomed; it just has farther to go than 3-D movie displays, which have been around a lot longer.
And while Banks acknowledges that more research is needed to fully assess the long-term visual effects of 3-D viewing, the optometrist sounds optimistic.
“I think it’s an exciting opportunity, so I hope these (3-D TV) problems get solved,” he said.Tags: 3D Models, Electronics, Games and Gear, Movies, TV Broadcasting
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