At CHI 2009 (computer Human Interaction conference,) many new modalities of interface were demonstrated. Some were sublime, some ridiculous.

One of the more practical, was the product of a team from ETH Zurich's Wearable Computing lab. Vaguely resembling the bastard child of a set of safety glasses and a HMD, the EOG goggles are an eye movement tracking system, that requires no external hardware to operate.

The prototype might look a tad convoluted, but it is an elegant solution to eye tracking, that is cheap to create, and lightweight to wear. Refined units could very easily be quite streamline.

EOG or electrooculography is a way or measuring the resting potential of the retina of the eye. It is usually a way to measure the position of the eye. Electrodes on either side of the eye are exposed to more or less of the retina as the eye moves. The difference in potential between the two, showcases the degree of movement of the eye, and thus where it is looking. With electrodes positioned above, below, and to either side of the eyes, the goggles can accurately calculate horizontal and vertical movements.

The technique can also be used to determine the brightness of ambient light, by measuring reflection off of the retina before it adjusts.

The benefit is that no video tracking is required, greatly reducing both weight and processing power in one fell swoop.