A couple of weeks before the release of Samsung's Galaxy SIV, an anonymous employee who has played with the phone divulged to The New York Times that the phone will track your eyes as you read, scrolling through along with your pace, a feature that sounds a little bit nauseating. This person did not explain how exactly this would work. But, basically, as you're reading along, the phone will magically know when you've hit the bottom of the page and scroll down, meaning no more thumbing. In theory, the idea sounds useful. But, it all depends on how well the technology can follow along.
The feature matches a trademark Samsung has filed for the "Samsung Eye Scroll," as the Times's Brian X. Chen discovered. The description in the application doesn't explain the technology behind the feature, but it matches the functions: "Computer application software having a feature of sensing eye movements and scrolling displays of mobile devices, namely, mobile phones." A Google patent search also pulls up what looks like a related invention application, filed last year: "Method of Controlling an Object by Eye Motion for Electronic Device." It describes using a CMOS or a CCD sensor to detect eye motion to "output a first control signal to a virtual object without touching said display, said user being located in front of said at least one image sensor and keeping said display with a distance." So, even if this thing doesn't show up in the Galaxy S IV, Samsung definitely has its eye on eye-controlled devices.