As with the Wii before it, early reports of 3DS-related maladies are already beginning to hit the internet, apparently. I expected this to happen.
For several months after the Wii's release, stories and images of black eyes and broken tv sets from errant Wii remotes were everywhere.
With the impending release of their latest system I wondered how long it would take for the eye strain and brain damage complaints to appear; despite abundant warnings - on the packaging, on the menu screen, and pretty much everywhere - about prolonged use of the 3DS (not to mention a prominent switch that just turns the 3D effect off).
I haven't had any trouble so far, but I've only used the 3DS in short spurts since getting it yesterday. But I generally don't have trouble with 3D movies or motion sickness in general, so I probably have a higher threshold then some.
Nintendo claims that taking a short break will alleviate any problems, and that there is no long term damage. But no one knows how an all day 3D marathon will effect people yet.
My theory is that it could look something like this: