Well, I will repost what I said in the other thread:
Troy Sanders (drummer for Mastodon) once said that it is best for a drummer to keep his back and neck as straight as possible and move as little as possible. I believe the same is true for sitting at a desk. I try not to twist my back or my neck, unless I have to. So, yeah, my eyes are all over the place, but my neck isn't.
Therefore, while I think eye tracking could potentially work, in the future, I don't think it would be good to get into the habit of moving your head and neck all the time.
