Engineers say they have built a cheap device that lets disabled people control a computer with just their eyes.
The gadget comprises two video-game cameras, costing less than $A10 apiece, attached outside the line of vision to a pair of ordinary glasses, reported the team from Imperial College London on Friday.
The cameras relay the eye's movements to an ordinary computer, wirelessly or via USB, and use one watt of power, they say in the Journal of Neural Engineering.
In this way, test subjects could control a cursor on a screen just like a computer mouse.
"We have achieved two things: we have built a 3D eye tracking system hundreds of times cheaper than commercial systems and used it to build a real-time brain machine interface," said co-author Aldo Faisal.
"This is frugal innovation; developing smarter software and piggy-backing existing hardware to create devices that can help people worldwide ..."
It also allowed patients to interact more smoothly and more quickly than more expensive technologies that require electrode implants in the brain.
"We demonstrate here that by using mass-produced video game hardware, it is possible to produce an ultra-low-cost binocular eye-tracker with comparable performance to commercial systems, yet 800 times cheaper," the researchers wrote.
The technology offers hope for restoring some level of independence to people who do not have use of their hands.
Other low-cost eye-tracking systems developed in the past had much lower performance, they added, while commercial-grade systems mainly used in research cost more than $A20,000).
To demonstrate their gadget's functionality, the team got subjects to play the video game Pong - using their eyes to bat a ball bouncing around on a computer screen.
Six of the subjects who had never done this before, achieved a "respectable score", said Faisal.
The researchers said they solved the problem of involuntary blinking in controlling the computer.
Many systems use a blink to represent a mouse click, but the team calibrated their system to work on a single-eyed wink instead.
They were also able to calibrate how far into the distance their subjects were looking, holding promise for future applications that may allow people to control an electronic wheelchair simply by looking at where they want to go.