The 3-D question

3-D movies like Monsters vs. Aliens hurt your eyes. They always have, and they always will. - Slate Magazine

Oh. I was planning on taking the kids to see Monsters vs Aliens this weekend in 3-D version. Now, I'm not so sure after reading the above article.

One interesting thing I didn't know:

Five percent to 8 percent of the population is stereoblind and can't convert binocular disparity into depth information. That means they can't appreciate any of the 3-D effects in a RealD or Imax movie. An additional 20 to 30 percent of the population suffers from a lesser form of the deficit, which could diminish the experience of 3-D effects or make them especially uncomfortable to watch.

How do you know if your kids are within the 20 to 30 %?

And here's something presumably rare, but surprising none the less:

There's already been one published case study, from the late-1980s, of a 5-year-old child in Japan who became permanently cross-eyed after viewing an anaglyph 3-D movie at a theater.