3D movies are messing with your depth perception
Apparently when you watch a 3D movie with those annoying glasses (people like me, have to sit for a couple hours ridiculously wearing two pairs of glasses at the same time), the experience messes with your depth perception, leading to a condition called “binocular dysphoria”. Mark Pesce, who did virtual reality development work for Sega in the 90s writes about this phenomenon:
Virtual reality headsets use the same technique for displaying 3D as we find in movies or 3D television sets – parallax. They project a slightly different image to each one of your eyes, and from that difference, your brain creates the illusion of depth. That sounds fine, until you realize just how complicated human depth perception really is. The Wikipedia entry on depth perception (an excellent read) lists ten different cues that your brain uses to figure out exactly how far away something is. Parallax is just one of them. Since the various movie and television display technologies only offer parallax-based depth cues, your brain basically has to ignore several other cues while you’re immersed in the world of Avatar. This is why the 3D of films doesn’t feel quite right. Basically, you’re fighting with your own brain, which is getting a bit confused. It’s got some cues to give it a sense of depth, but it’s missing others. Eventually your brain just starts ignoring the other cues.
That’s the problem. When the movie’s over, and you take your glasses off, your brain is still ignoring all those depth perception cues. It’ll come back to normal, eventually. Some people will snap right back. In others, it might take a few hours. This condition, known as ‘binocular dysphoria’, is the price you pay for cheating your brain into believing the illusion of 3D. Until someone invents some other form of 3D projection (many have tried, no one has really succeeded), binocular dysphoria will be part of the experience.
The problem isn’t so much 3D movies, though. It’s when the leap comes to 3D TVs and 3D computer games. Pesce postulates that the hours that kids could spend in front of a 3D display might, alarmingly, ruin depth perception… permanently. I don’t know if there is any medical basis for Pesce’s article, but it sounds plausible (but don’t all urban legends sound plausible?).
1:13am 
