Most of that essay came across as pointless to me. First, I was somewhat lost by a sound engineer arguing visual science; didn't seem the right expert for the case.
And then the first half is filled with handwavium pseudoscience:
"Somehow the glasses "gather in" the image"
"something to do with the amount of brain power"
Then there's an explanation of the focus-convergence problem that about makes the case against movies as a whole: looking at the illustrations of the salt shaker and mountain vista, I found that I was having a hard time processing the image. The in focus aspect forces me to look at it, so I can't see the out of focus part. And when I deliberately gaze on the out-of-focus portion, it makes my eyes swim because I want to focus, and I can't.
600 Million Years of evolution did not prepare Neandertal Man to deal with intentionally blurred images.
Ah yes, then it truly goes out to lunch with pop-science nonsense about how we're evolved to not watch 3D movies. Oddly, he doesn't consider that man also did not evolve to look at a 40-foot screen about 30 feet away an perceive 10,000-feet tall mountains 20 miles away. Nor did we evolve to watch the world in Black and White. But somehow we've had a century of such unnatural artistry.
I'm also pretty sure that hunting the Savannah didn't prepare us to view each other as oddly colored, mis-shapen polyhedrons, but Ebert doesn't rail against Picasso's offense to evolution.
Yes, some people get headaches watching 3D movies. That's unfortunate. But 3D filmmakers seem to be getting better at mitigating those problems. Maybe it's a fad, maybe not. For the rest of us who can enjoy 3D, I hope it sticks around; it's quite fun.
So why does Ebert have to view this not as a personal preference--, but as an offense to nature and perversion of humanity? For someone who rails against fundamentalist dogma, Ebert gets awfully fundamentalist-dogmatic about 3D.