Market projections rosy, but health effects are still unknown

Rick Merritt EE Times (03/02/2010 7:08 PM EST)

The rise of 3-D TVs will not be a slam dunk. Risk factors that could depress the ramp include whether consumers will adopt the necessary glasses and whether there will be enough high quality content available to spark consumer interest.

"The quality and quantity of content is probably the most important issue in my mind," said Chinnock. "If you only have three Blu-Ray discs that will get pretty boring, pretty quickly—and bad 3-D content could create a backlash," he said.

Indeed, experts in human perception have been coaching stereographers in Hollywood about how to avoid problems such as the convergence-accommodation effect that they have shown can cause eye strain and headaches.

Researchers have yet to study the correlations between specific eye movements and symptoms of eye strain. Academics at Berkeley, the University of Southern California and the Bangor University, Wales, are trying to find funding for such studies.

"There's hardly any data, so there's a need for vision scientists to map that out properly for different populations," said Simon Watt, a lecturer at Bangor University.

Watt estimates it could cost half a million dollars to conduct a three-year study of the issue.

"My goal is to develop a set of guidelines about the limits of stereo 3-D and where fatigue comes in," said Watt. "Ideally I'd like to know if the effects hold true for people throughout their life span," he said.

The brain is not wired to re-adjust perception of 3-D images in space, Watt said. Thus significant exposure to 3-D TVs could cause neurological re-wiring in the brains of children who use such sets for extended periods.

"Lots of aspects of visual development are still not fixed even by nine years old," Watt said.

If vendors spin out stereo 3-D computer games and PC applications any problems could become heightened because the perceptual issues are intensified as the distance to the screen becomes smaller, Watt said. In addition, "your ability to accommodate [for stereo 3-D images] significantly decreases with age," he said.

It would be very hard to do longitudinal studies of the impact of intense 3-D TV and PC exposure from both a practical and an ethical standpoint, Watt said. "In a sense the experiment will be done in people's living rooms if these things become widespread," he said.

"I don't think there's any compelling argument that if you look at this sort of content as a kid something terrible will happen, so I wouldn't be to alarmist about it—but the point is we don't know," said Watt. "There is, however, some small indication that if you have a diet of blurry images it can accentuate myopia, for example," he added.

Watt said he and other researchers want to sound "a note of caution, not an alarm bell" about 3-D TVs.

The good news is, "the industry does seem to want to know the answers to these questions, so I'm confident there's a will out there to do this work," he said.

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