Keep your eye on the ballpoint

A new technology that uses only the eyes to write in cursive script gives hope to people who have lost the use of their limbs.

Developed by Jean Lorenceau, of the Pierre-and-Marie-Curie University in France, it tricks the neuromuscular machinery into doing something that was thought impossible: voluntarily producing smooth eye movements in arbitrary directions. The report was published last week in Current Biology.

'It then becomes possible to generate smooth renderings of digits, letters and words, or even one's signature,' says Lorenceau, who tested the technology on six participants.

Although learning rates differ between people, he says it typically takes three to five 30-minute sessions performed on different days to learn to make these smooth eye movements. The technology relies on changes in contrast to trick the eyes into the perception of motion. When viewing that changing visual display, people can learn to control their eye movements smoothly and at will. In everyday life, smooth pursuit eye movement is used to track moving targets, Lorenceau explains.

While our eyes never cease to move, it is normally impossible to control those movements smoothly in any direction.

The new technology could be of benefit for those with motor neuron disease, and cerebral palsy and tetraplegics, says Lorenceau. He says by using cursive eye writing, people who can't move their limbs could communicate by drawing figures or their own signature at will.