New stereo 3-D smartphones and mobile devices might hurt you and your patients twice—first in the wallet, then in the eyes. Researchers have found that using stereo 3-D devices for an extended amount of time can cause visual discomfort, fatigue and headaches. The root cause may be the demand on your eyes to focus on the screen while simultaneously adjusting to the distance of the content, according to a new Journal of Vision study. 

This conflict stems from vergence-accommodation. “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,” explains study author Martin S. Banks, Ph.D., 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.”

During a series of experiments on 24 adults, Dr. Banks and his research team observed how placing content in front of or behind the screen affected viewer discomfort. With devices viewed at a short distance (mobile phones, desktop displays), stereo content placed in front of the screen was less comfortable than content placed behind the screen. Conversely, stereo content placed behind the screen was less comfortable when viewing at a longer distance (movie theater screens).

With the explosion of stereo 3-D imagery in entertainment, communication and medical technology, the investigators suggest guidelines be 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,” Dr. Banks says.

Shibata T, Kim J, Hoffman DM, Banks MS. The zone of comfort: Predicting visual discomfort with stereo displays. J Vis. 2011 Jul 21;11(8). doi: 10.1167/11.8.11.