Comment Re:Eye strain (Score 1) 134
Nope. It's already been done. For nearly 25 years, I think (it's referenced in Dennett's "Elbow Room"). The computer can track the position of your pupils in relation to the screen, and since eye movement is made up of tiny ballistic trajectories, the computer can figure out where your focus is going to land next, and can "clear" the data at that point, and then "garbage" the data at the point that your eye is no longer looking at. People take in groups of symbols in chunks when they read and then hop over to the next bit and the computer can switch data faster than a person can notice, so the person who's reading the screen sees nothing but normality, while anyone who's looking over your shoulder (unless they had the exact same focus at the exact same time, which is incredibly unlikely) only sees gibberish.
Note that it only works with text. I'm not sure it would work with any sort of non-text graphical information.