Eye expert: Watching 3D for "an hour-and-a-half" is "the maximum"

A UK optometrist has told VG247 that prolonged 3D use is a "worry," following the updating of PS3's terms and conditions yesterday to warn against "eye-strain, eye-fatigue or nausea" when viewing the technology.

James Sutton, eye specialist and MD of British eye health company Butterflies Healthcare, said that watching 3D content over extended periods - when playing a game, for example - would cause people to work their eyes far beyond the "maximum" time experienced when seeing a movie.

"I would have said about an hour, an hour-and-a-half, to be about the maximum," said

"A lot of people do say when they come out of the cinema that they are aware they've done something different with their eyes, even if it's not to the extent of a headache or sickness, but they're aware that it was hard work to watch. I'd have said that was more than enough.

"I'd would worry about people spending hours doing it, I must say."

Sony warned 3D users yesterday that they should take "regular breaks while watching 3D video or playing stereoscopic 3D games," and that people should "take breaks that are long enough to allow any feelings of discomfort to subside."

Throwing up, on the up

Sutton said that more people are likely to report issues such as motion sickness, eye-strain and migraine as 3D is used for longer periods.

"I do think the number of people reporting problems with it will go up the more they use it," he said.

When told that Ubisoft had said last week it expected 3D to be fully mainstream in three years, Sutton said provision needed to be made to turn the effect off if needed.

"If there isn't a way when you're watching something to say, 'Actually, I don't want to watch this in 3D,' then I would say yes, it is worrying, because you're not catering for a significant proportion of people who are going to struggle," he said.

In terms of people who are likely to experience eye-strain and nausea from watching 3D, quite what a "significant proportion" actually means simply isn't known at the moment.

"I don't know, is the honest answer," said Sutton. "I would guess at about 10 percent, something like that."

The health issues of watching 3D are likely to be exacerbated by playing games for extended periods, but that's not to say using the tech for shorter times hasn't already 'thrown up' issues for the film industry.

There were many reports of those watching 3D movies such as Avatar experiencing motion sickness and eye-strain over the Christmas period last year, despite the movie being 162 minutes long.

Artificial situation

But what exactly is the problem? Sutton explained.

"3D presents each eye a slightly different image, which the brain has to then merge together to create the 3D image," he said. "Normally, when we look at something on a cinema screen, both eyes are looking at the same point on the screen, which is what we do day-to-day when we look at things.

"When you create 3D, the two images have to be separated slightly, so your eyes are having to look at things slightly removed from each other; that's what gives you the 3D depth. That's an artificial situation, because you're trying to look at something coming out at you that isn't really coming out at you.

"It's quite a lot of work for you to do that for a sustained period... There's a proportion of people that find that, for the prolonged period of time that they're having to do it, it will cause eye-strain, as they're working too hard to create what is, in effect, a visual illusion."

3D formed a sizeable part of Sony's E3 showing in June, with games like Killzone 3, Crysis 2 and more arriving in the next 12 months sporting 3D as a significant feature.

Don't worry if 3D use does make you sick, though. Sutton reckons any adverse affects won't last long.

"I don't think it's likely that it's going to be a permanent problem," he said.

"It's just a worry that you're going to see more people with problems as a result of doing this."