WASHINGTON: We are living in a world where everyone is glued to their smartphones and other electronic gadgets. So it is no surprise that mobile devices and other stereo 3D devices are really hurting our vision.

According to a new study, prolonged viewing of mobiles and 3D devices often leads to visual discomfort, fatigue and even headaches because our eyes have to focus on the small screen and simultaneously adjust to the distance of the content.

This phenomenon is called the vergence-accommodation conflict.

"When watching stereo 3D displays, the eyes must focus -- that is, accommodate -- to the distance of the screen because that's where the light comes from. 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," said author Martin S. Banks, professor of optometry and vision science, University of California, Berkeley.

The researchers conducted a series of experiments on 24 adults and observed the interaction between the viewing distance and the direction of the conflict, examining whether placing the content in front of or behind the screen affects viewer discomfort.

The results demonstrated 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 than content placed behind the screen.

Conversely, when viewing at a longer distance such as a movie theater screen, stereo content placed behind the screen --appearing as though the viewer is looking through a window scene behind the screen -- was less comfortable.

"Discomfort associated with viewing Stereo 3D is a major problem that may limit the use of technology. We hope that our findings will inspire more research in this area," said Banks.

The study appears in the Journal of Vision.