A minority of viewers worldwide have experienced discomfort while watching 3D screenings of the film, with symptoms including nausea and sweating, international media have reported.
But moviegoers were no more likely to suffer motion sickness at Avatar than any other film, Associate Professor Robert Jacobs at Auckland University's optometry department said.
"The 3D movies have been around for a long time -- there's nothing specific about Avatar," he told NZPA.
Motion sickness was caused by a conflict between the senses, and even traditional 2D movies had the potential to make people feel ill, he said.
"You think the environment's moving because so much of what you're seeing is moving, but in fact the rest of your senses, your balance, says you're not moving."
Some people were more prone to motion sickness than others, but there was little they could do to prevent it, he said.
"Certainly closing one eye or getting rid of the glasses isn't going to change things."
Auckland couple Tania and Raymond Lorenzen are among those who have fallen ill at a 3D screening of Avatar.
Mrs Lorenzen said she started to feel nauseous about 10 minutes into the film and had to close her eyes, while Mr Lorenzen later had to rush from the cinema to throw up in the bathroom, The Dominion Post reported.
Thousands have flocked to Avatar since its release five weeks ago, but New Zealand's largest theatre chain, SkyCity Cinemas, has not yet received any reports of moviegoers falling ill.
Over 36,000 people had seen the film at the IMAX 3D theatre in Auckland, but so far none had made a formal complaint, SkyCity marketing manager Lisa Chambers said.
"Its pretty full-on in 3D, and people are walking out going `wow', but we actually haven't had any formal reports of anyone being sick," she said.
"It could be that someone has, but they certainly haven't expressed it to us. We have staff who collect the glasses at the end, and certainly they haven't had any reports themselves, either."
Most people had an overwhelmingly positive reaction to the film, with some returning to see it two or three times.
"It's huge. We were just looking at the numbers and they're still selling out.
"If you want to see Avatar at the moment you have to book a couple of days in advance still, which is quite phenomenal within week five of its release. It's still got a huge amount of steam in it."
Moviegoers who had to leave early due to motion sickness would get a full refund, she said.
"If they came out part-way through the film, absolutely. But if they watch the film all the way through to the end and then decide they'd like a refund, I'm not sure about that. Realistically they've still experienced the entire film."
source: newshub archive