We had a go on the Spring and quickly learned how to control it with our eyes: much like the Xbox Kinect, in order to make a click we had to hover the cursor over (or fix our eyes on) a desired button until the former completes a spin. The tracking was surprisingly accurate, except we had to take off our glasses for it to work; that said, the other glasses didn't exhibit the same issue, so the culprit could be just some coating on our lenses. Another problem we found was that it only took a quick jiggle with our eyes to cancel the spinning countdown, so full concentration is required to use the Spring. This shouldn't be a problem outside a noisy event like Computex, anyway, and if you need more convincing, we were told that a disabled Taiwanese professor managed to hit 100,000 Chinese characters within three months using phonetic input on the the same rig -- he's planning on releasing a new book soon. Have a look at our eyes-on video after the break for a better idea on how the Spring works.
Utechzone Spring eye-tracking system hands-on