Prolonged exposure to VR displays can trigger nausea, motion sickness

Washington: People with the best 3D vision are also the people most likely to suffer from motion sickness while using virtual reality displays, a new study has found.

Researchers demonstrated this by playing motion-heavy videos for study participants through a Oculus Rift—3D virtual reality headset worn like a pair of goggles.

Nearly two-thirds of the study subjects quit watching the videos early, overcome by nausea in the virtual environment for much the same reason discomfort catches up to people in real-world situations.

Motion sickness is the product of mismatched sensory information. "The classic example is reading in a car," said Shawn Green, a professor at the University of Wisconsin-Madison.

"Lots of people can't read in a car because if you have a newspaper in front of you, your visual system says you're still," Green said.

But you're not still. While the newspaper may not be moving, the car speeds up and slows down, turns corners and climbs hills. All this movement registers in the vestibular system, a series of organs in the ear that aid balance by telling us which way is up.

"In the car, those balance cues say you're accelerating, and that's a big mismatch with your eyes on the still newspaper. That mismatch makes you nauseous," Green said.

Oculus produces that mismatch in reverse, according to Bas Rokers, UW-Madison psychology professor. While the 3D movies depicted flying over forests and under bridges, the headset and the viewer are not actually moving. "And observers don't have agency—they can't control the motion," Rokers said.

"If they were in control, they could predict what things should look like. That would probably help them ease the discomfort," Rokers said. Researchers found that the people in their study who reported the most discomfort were also best at judging the direction of objects moving towards or away from them.

"It seemed natural that people who may be very sensitive to 3D motion might pick up on the fact that the visual motion signals provided in the Oculus can be inconsistent with balance signals," Rokers said.

Interestingly, it was just perception of moving objects that predicted motion sickness. Skill in identifying the relative depth of still objects was not connected with the 3D discomfort. Results of the two tests seem independent.

"We've had people with perfectly good depth perception who couldn't do the 3D motion tests, and the exact opposite -people who could do the 3D motion tests that would be classified as stereo blind by the static test," Green said.

The study was published in the journal Entertainment Computing.