We're used to the idea of communicating with our eyes — but soon, we could be using just our eyes to write words, or to control machines. A French scientist accidentally figured out how to control his eye movement enough to be able to write on a computer screen — and in the process, may have revolutionized how we communicate with paralyzed people.
Our eyes are actually incredibly good at smooth movement — but it's not something we can control. Generally, we only engage what's known as "smooth pursuit" when tracking a moving object. If you try and do a slow pan with your eyeballs without something to fix on, you'll generally just shift around in short bursts. But a scientist accidentally discovered a way to engage smooth pursuit without a subject to look at. Even more amazingly, he trained his eyes to do it at will.
Top image: Charlotte Gomez/Wall Street Journal — click the link an exclusive video of the device in action.
Jean Lorenceau of the Université Pierre et Marie Curie was looking at an unusual visual display in his lab, and discovered that he could detect and control his own eye movements. Building on this, he trained himself and six others to control their fine eye motion, to the point where they could write cursive.
The display he used was described as:
a display screen filled with randomly distributed static disks modulated in contrast about the background luminance at a moderate temporal rate (>12 Hz). When the eyes are at rest, this display appears as a field of faint static disks. However, any movement of the eyes creates a shift of the visual pattern on the retina.
This tricks the eye into behaving like it's tracking motion — and from there, Lorenceau was able to train the subjects to control the fine motion of their eyes. First, by tracking an object on the screen, then by having red dots show where the pupils were pointing, finally removing all fo this, and lowering the contrast on the screen.
After all of these methods, subjects were able to comfortably and smoothly move their eyes for more than 10 seconds at a time, plenty enough to scrawl out words.
This not only opens doors for people who need to use their eyes to communicate — patients with ALS, tetraplegics, cerebral palsy, locked-in syndrome — but also might be a way to improve eye control in people who rely on intense hand-eye coordination. [Current Biology]