Is Your Smartphone Making Your Eyes Tired?

August 29, 2011

I sometimes feel like the last person on the planet who has a mobile phone that does just that – make phone calls. The rise of the new so-called ‘smartphones has been fast and furious and although we know of the dangers of over use of mobiles, it seems the new technology is throwing up another problem.

Several reports indicate that prolonged viewing of mobiles and other stereo 3D devices leads to visual discomfort, fatigue and even headaches. As more people are using smartphone, ipads, kindle readers and 3D game players this situation is going to get worse, not better. According to a new study reported in the Journal of Vision, the root cause may be the demand on our eyes to focus on the screen and simultaneously adjust to the distance of the content.

This is technically known as vergence-accommodation, and it this conflict and its effect on viewers of stereo 3D displays that the study has reported on.

Martin S. Banks, professor of optometry and vision science, University of California, Berkeley is the lead author of the study and comments: “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.”

Through a series of experiments on 24 adults, the research team 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.

At the moment we are talking discomfort, and the study was on adults, but presumably long term use and by youngsters will have a more serious impact. My local cinema now offers virtually every film as 2D (or what we used to call just film) and 3D and it is to the latter that the younger audience are drawn as when the new Harry Potter film was launched the 3D showing sold out faster. There has been an explosion of stereo 3D imagery in all areas, not just film and tv, but communication and medical technology as well.

“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,” added Banks.
The authors also propose guidelines be established for the range of disparities presented on such displays and the positioning of viewers relative to the display but in a world where we want colour, excitement and pzazz from our entertainment it may be that self – or parental – control might be the first step to avoid eyestrain and headaches.


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