PhD candidate Stephen Vickers and his team at De Montfort University in Leicester, UK are designing software for people with disabilities who use eye-gaze control to be better able to play video games. Here are videos of Stephen demonstrating the software, called Snap Clutch, in World of Warcraft and Second Life:
(World of Warcraft)
In a paper Vickers co-authored for the 4th Cambridge Workshop on Universal Access and Assistive Technology ("Gaze Interaction with Virtual On-Line Communities: Levelling the Playing Field for Disabled Users"—available in his list of publications), eye gaze was compared to mouse control in the game Second Life. While eye-gaze performed comparably in moving the avatar from place to place and in manipulating objects, it didn't do well for using applications within the game (thanks to the applications' tiny buttons) or communicating in-game via an on-screen keyboard. A particular problem involved reading distracted looking as choices, so that if a player noticed a tree on the screen and looked at it, the avatar would run into the tree. The paper concluded that: "The types of errors found suggest a need for a lightweight clutch mechanism whereby gaze control can be activated and deactivated quickly and effortlessly. A control action can be applied by eye and then gaze control is deactivated to enable the user to...look at the objects nearby" (p. 12).
Snap Clutch is just such a "lightweight clutch mechanism." According to a New Scientist article, the software lets players switch between different actions and choices using eye-gaze, as well as pause the gaze control entirely:
"Glancing momentarily off-screen in a particular direction switches between different functions, for example, to a mode that rotates the avatar or viewpoint, or to call up transparent icons dragged onto game objects to perform a particular action.
"A 'gaze gesture' is also built in to temporarily turn off the eye-gaze functions altogether, to avoid unintentionally selecting an item while looking around the screen."
FYI: De Montfort University also hosted last year's Communication by Gaze Interaction (COGAIN) conference, where the topic was "Gaze-based Creativity, Interacting with Games and On-line Communities."