Technology is being developed to allow people with severe motor disabilities to play 3D computer games like World of Warcraft using only their eyes.

Since the 1990s, gaze technology has helped people with conditions such as motor neurone disease (MND), cerebral palsy and other "locked-in syndromes" to control 2D desktop environments and communicate using visual keyboards.

Users typically guide a cursor with their eyes, staring at objects for a time to emulate a mouse click. But that is too laborious to let users to match the speed and accuracy of real-time 3D games, says lead researcher on the project, Stephen Vickers, of De Montfort University, Leicester, UK.

His team is developing the software as part of the EU-funded project Communication by Gaze Interaction (COGAIN).

Gaze gaming

"Even though a user in, say, Second Life might look as if they are able-bodied, if they can't operate and communicate as fast as everyone else, they could be perceived as having a disability," he told New Scientist, adding that there is a privacy issue for players who may prefer not to reveal their disability in the virtual world.

In virtual worlds, gamers need to perform a whole suite of commands including moving their character or avatar, altering their viewpoint on the scene, manipulating objects and communicating with other players.

Eye-gaze systems bounce infrared light from LEDs at the bottom of a computer monitor and track a person's eye movements using stereo infrared cameras. This setup can calculate where on a screen the user is looking with an accuracy of about 5 mm.

Vickers' software includes the traditional point and click interface, but includes extra functions to speed up certain commands.

Power moves

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.

"The eyes are perceptual organs, not designed for pointing and selecting," explains Vickers. "You can't turn them off, like you can lift your hand off the mouse."

Confidence boost

The developments are "hugely important", according to Mick Donegan, who works with severely disabled children and adults at Oxford-based charity and COGAIN partner, The ACE Centre.

"Enabling someone to express themselves and engage with people in ways that they can't do in real life – because they are restricted to a wheelchair or a bed – can have a really positive effect on their self-esteem and motivation," says Donegan.

Vickers hopes to begin trials of the software with people with locked-in syndrome within the next year.

A paper on the new system was presented at the Eye Tracking Research & Applications Symposium 2008 in Savannah, US.

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