I think it differs from person to person on whether they get an headache when watching 3D. I regularly watch 3D movies in theaters and have never got a headache, whereas my friend gets it every time.
Here's a good article on how to avoid 3D eyestrain.
Today3D: Basic rules to avoid 3D eyestrain
The article makes an important point on how kids don't get headache when they watch 3D.
"You will not find many kids complaining about 3D eyestrain. There are few reasons for that, but the most important one is that they grow up into 3D and they do not need to learn how to watch it."
Here's a good article on how to avoid 3D eyestrain.
Today3D: Basic rules to avoid 3D eyestrain
The article makes an important point on how kids don't get headache when they watch 3D.
"You will not find many kids complaining about 3D eyestrain. There are few reasons for that, but the most important one is that they grow up into 3D and they do not need to learn how to watch it."