Training with an eye-tracking technology could improve eye control for people with dyslexia and experts who rely on excellent vision such as surgeons and athletes, a researcher says. (Damian Dovarganes/Associated Press)

People who have lost the ability to use their arms and legs may soon be able to "write" with their eyes with the help of new technology developed in France.

The eye-writing technology tricks the neuromuscular machinery into doing something that is usually impossible: to voluntarily produce smooth eye movements in arbitrary directions.

"For persons deprived of limb movement, this offers a fast, creative, and personal means of linguistic and emotional expression," Jean Lorenceau, director of research at the Centre National de la Recherche Scientifique (CNRS) and the brains behind the new technology, says in a paper published in Current Biology.

Lorenceau's technology uses an infrared eye-tracker mounted on top of the head to record eye movements. Custom software creates an interactive visual display.

After three, 30-minute practice sessions, most people involved in the study could make their eye move smoothly to draw cursive letters, numbers and even their signature on to the screen.

Like invisible ink, they couldn't see their letters but only a series of flickering white and black dots on a grey background.

These dots create an illusion called "reverse phi motion," making it seem like the screen is moving in the same direction as the eyes.

It's this illusion that allows people to make smooth eye movements in any direction they like, says Lorenceau.

You can track a moving car smoothly, explains Lorenceau, but with a non-moving background like a building our eyes make jerky movements called saccades as they rush to focus on one spot and then another.

"If you try to smoothly move your eyes, this reveals to be impossible," he says. "The visual system that we have requires a moving target [to make smooth eye movements]."

Training in eye awareness

Generally, people know what they see, but are not aware of how their eyes are moving, says Lorenceau.

"This display is the opposite, you don't pay attention to what you see, but what you do with your eyes," he says.

He speculates that training with the technology could also improve eye control for people with dyslexia and experts who rely on excellent vision such as surgeons and athletes.

However, he is quick to add training did not work with everyone. In the small group of six, only four could master the technique.

Mike Horsley, an associate professor at the Learning & Teaching Education Research Centre director at CQUniversity, says the research is promising.

"He's thought of this particular issue in saccade movement in a completely different way," he tells the Australian Broadcasting Corporation.

"The next stage for [Lorenceau] and his team is to use more subjects and find out if people can really do it."

Horsley says eye-tracking research is growing with the first EyeTrack Australia Conference held recently and the variety of applications of eye-tracking research "was pretty amazing".