How Eye Tracking Works
As the term implies, eye tracking is simply a technique used to follow (keep track) a person’s gaze. It makes use of a device called an eye tracker which measures the positions of the eyes and its movements. There are different kinds of technologies available that is used for eye tracking but the most common eye tracker uses a video camera to record the eye(s) and its movements. This is also the method used by (web) usability consultants/engineers.
What happens is that the camera has a special feature (the eye tracker!) which enables it locate the center of the pupil. This is usually done using infrared and near-infrared light. Before data is gathered during eye tracking the camera is calibrated for each user. Calibration takes only a few seconds. The data is gathered by simply allowing the user to go about browsing the a website the way he/she normally would. Specific tasks can be given to the user since eye tracking can be done simultaneously with other usability tests. Note that the camera used for eye tracking is usually placed unobtrusively so that it will not bother the user and thus affect the outcome of the test.
After the data is gathered the usability consultant will then interpret the data. Images showing browsing pattern of the test subject (the average user) should of course be part of the report making it all very easy to understand.
If you haven’t done eye tracking and want to improve your website design I suggest you do this before investing to redesign your website. You might be surprised at how much you can learn and how much it will affect your approach to web design.