This morning, we have learned of a new patent that was awarded to Google that could allow Google Glass users to unlock their device by simply moving their eyes. This could open up all sorts of possibilities not only for use within Google Glass, but for further augmented reality situations.
US patent application number 20130135204 is described by Google as "Methods and systems for unlocking a screen using eye tracking information." It appears that Glass would display some sort of moving objects such as a bird flying across the screen. It would then track your eye movement and if everything is correct, it would unlock your screen.
"The computing system may determine that a path associated with the eye movement of the user substantially matches a path associated with the moving object on the display and switch to be in an unlocked mode of operation including unlocking the screen," the company said in the filing. To me, it seems that eye tracking technology is a given for Google Glass and I kind of expected it to be there from the beginning.