Why 3-D Movies Will Always Hurt Your Eyes

Did the 3-D version of Monsters Versus Aliens make you want to barf, even though you liked the movie? Now Slate's Daniel Engber explains why - and says the problem may never be solved.

Engber writes:

Vision researchers have spent many years studying the discomfort associated with watching stereoscopic movies. Similar problems plague flight simulators, head-mounted virtual-reality displays, and many other applications of 3-D technology . . .

One potential explanation for the discomfort lies with the unnatural eye movements stereoscopy elicits from viewers. Outside of the 3-D movie theater, our eyes move in two distinct ways when we see something move toward us: First, our eyeballs rotate inward towards the nose (the closer the target comes, the more cross-eyed we get); second, we squeeze the lenses in our eyes to change their shape and keep the target in focus (as you would with a camera). Those two eye movements-called "vergence" and "accommodation"-are automatic in everyday life, and they go hand-in-hand.

Something different happens when you're viewing three-dimensional motion projected onto a flat surface. When a helicopter flies off the screen in Monsters vs. Aliens, our eyeballs rotate inward to follow it, as they would in the real world. Reflexively, our eyes want to make a corresponding change in shape, to shift their plane of focus. If that happened, though, we'd be focusing our eyes somewhere in front of the screen, and the movie itself (which is, after all, projected on the screen) would go a little blurry. So we end up making one eye movement but not the other; the illusion forces our eyes to converge without accommodating.

This is just one part of a fascinating article about the ways 3-D affects our vision - and how all the new 3-D technologies won't be able to fix the basic problems that cause nausea, dizziness, and (potentially) damage our ability to focus our eyes.

via Slate

Image by Souris Hong Poretta