To date, there are four different eye-tracking technologies on the market. Two use cameras mounted on or near a computer monitor and two types use a camera mounted on glasses or headgear that the user wears. Each system has valuable features and specific limitations. Ultimately, the needs and skills of the user will determine the appropriate system to serve their purposes. The Eyegaze Communication System, by LC Technologies, Inc., uses a video camera, mounted below a monitor, and a video processing system to observe one of the user's eyes as it navigates the display.
Nothing is attached to the user's head or body.
The Quick Glance, by EyeTech Digital, also uses a camera mounted on the monitor to track eye movement and software to translate it into mouse movement. The Vision Key, by H.K. EyeCan Ltd., uses a key chart placed in a viewer mounted on a pair of eye glass frames and operates as a stand-alone communication system, and can attach to a computer to perform keyboard and mouse emulation. Although an eye-control system may appear as an option when all other controls have failed, there is some evidence that the loss of ocular motor control, often found in later stages of diseases such as ALS, can adversely affect the ability to use it. The Study A study using subjects with normal ocular motor control is being conducted to compare eye-tracking systems and their features. One of the considerations is user position.