Originally Posted by JimP
Did anyone notice how people who viewed the 3D demos at CES and at the Panasonic truck tour said that after a while they removed the glasses as they were fatigued and felt some eye strain?
Sure, but nothing permanent happened to them.
It's no worse than spinning yourself around in a circle and getting dizzy. You haven't scrambled your brain. All you've done is thrown off your equilibrium for a bit.
Stare at one color for a few minutes, then look at the rest of the room. Everything will have a color tint toward the other end of the spectrum for a moment. For example, staring at a green chromakey screen for a few minutes will result in everything looking a bit red or magenta when you look away. That's why when blue screen technology was first being used (before green screen) in movies like "Spaceballs", crew members wore yellow tinted glasses. That odd color tinting in your vision that occurs was thought to be damaging, so wearing the yellow lenses was a "protective" measure until the effects were understood.
If you wear contacts and seldom wear your glasses, you know that when you first put the glasses on for those rare occasions it usually results in a bit of temporary blurry vision.
Now, you can
hurt your eyes by exposing them to overly bright lights or light wavelengths known to be harmful, like UV or concentrated LASER frequencies. Illuminated displays will cause eyestrain if viewed for long periods of time, but that can usually be undone with either rest or looking away for a while.
Your brain is a very advanced and complicated computer. It's very adaptable, but sometimes takes a short time to do it fully. Your eyes will adjust to 3D viewing slowly (which is why you stop noticing it so much as the movies go along unless something really jumps out at you) and will adjust back to reality slowly (hence some dizzyness, eyestrain or fatigue).
Over time, your brain can adjust to about anything, including the loss of an eye completely or color blindness.
One can certainly assume that the longer you view a 3D presentation, the longer it will take to re-adjust after, but it's really not much different than adjusting to bright lights after being in a darkened room.
The reason for the odd feeling afterward is simple: you're brain is used to being fed images at the same exact moment from the same source. With 3D, there is a deliberate offset of the images that you can't process consciously, but your brain realizes is there. It's not hurting you so much as requiring your brain to switch gears faster than it normally would.
Now, if there was a way to slowly "bring you out" of 3D (like slowly fading up the lights in a theater), I'll bet few people would experience any negative symptoms. Instead, we yank off the glasses and walk out into the real world without taking time to adjust. It's no wonder you feel weird.