According to a new study by the "Journal of Vision," the root cause of visual discomfort from watching mobile and 3-D television displays may be the stress on human eyes to focus on the screen and simultaneously adjust to the distance of the content.
Scientifically referred to as vergence-accommodation, this conflict and its effect on viewers of stereo 3-D displays are detailed in a recent "Journal of Vision" article, "The Zone of Comfort: Predicting Visual Discomfort with Stereo Displays."
"When watching stereo 3-D displays, the eyes must focus — that is, accommodate — to the distance of the screen because that's where the light comes from," said Martin S. Banks, an author of the study and professor of optometry and vision science at the University of California, Berkeley. "At the same time, the eyes must converge to the distance of the stereo content, which may be in front of or behind the screen."
The research team observed the interaction between the viewing distance and the direction of the conflict, examining whether placing content in front of or behind the screen affects viewer discomfort. The results showed that with devices like mobile phones and desktop displays that are viewed at a short distance, stereo content placed in front of the screen — appearing closer to the viewer and into the space of viewer's room — was less comfortable to watch than content placed behind the screen.
"Discomfort associated with viewing stereo 3-D is a major problem that may limit the use of the technology," Banks said. "We hope that our findings will inspire more research in this area."
The team of investigators suggested future studies focus on a larger sample in order to develop population-based statistics that include children. With the explosion of stereo 3-D imagery in entertainment, communication and medical technology, the authors also proposed guidelines established for the range of disparities presented on such displays and the positioning of viewers relative to the display.
"This is an area of research where basic science meets application and we hope that the science can proceed quickly enough to keep up with the increasingly widespread use of the technology," Banks said.