Scientists at the University of Munich Hospital recently showed off their EyeSeeCam (link to PDF brief) head mounted control interface at the Hannover Messe 2009, an industrial technology fair in Germany. The EyeSeeCam tracks the viewpoint of the wearer's pupils and transmits that data to servo actuators that can control any number of mechanical devices such video cameras or even a robot, as shown above.
The device can be operated by remote control via WLAN, and only requires a standard laptop with a 6-pin firewire port. Although the EyeSeeCam was originally designed to study cognitive behavior, the inventors hope to bring the device to the commercial market in the not too distant future.
Via AFPBB News