Eye Tracking for Usability Testing

What is eye tracking?

“Eye tracking” is a term used to describe the techniques of measuring the point of gaze (where you are looking) or for determining eye/head position. There are numerous methods that exist today for measuring eye movements.

Uses of eye tracking

Eye tracking can be used to analyse applications as well as interacting with computers and machines.
The ability to measure eye gaze adds value to behavioural research and analysis, since human behaviour and thinking is reflected in where people look. There are many major areas of application including academic research e.g. cognitive science, psychology and medical research and market research. Punkyduck focus on the area of usability studies, such as advertising or package design and software or web usability.

History of eye tracking

Eye tracking studies have their origins in the 1800s, when studies of eye movements were made using direct observations. The first true eye tracker was composed of a contact lens with a hole for the pupil. The lens was connected to an aluminium pointer that moved in response to the movement of the eye. This was in the late 1800s.
Since then eye tracking has come a long way. The first less cumbersome eye trackers were built in the 1930s using beams of light that were reflected on the eye and recorded on film.
Today there are modern eye trackers that do not affect test subjects or users and that do not require extensive technical expertise. Non-intrusiveness and ease of use have been keys for taking eye tracking out of the research labs into broader use.
Currently at Punkyduck we use the Tobii T120 integrated eye tracker a non-intrusive device contained within a monitor. The device uses two cameras to record eye movement and so leaves test participants to move and act freely as they would normally.

Eye tracking techniques

Today’s most commonly used eye tracking technique started life in the late 1960s. Pupil-centre/corneal-reflection utilises image processing to detect reflections in a person’s eyes.
The accuracy depends on how precisely the image processing algorithms can locate the relative positions of the pupil centre and the corneal reflection. There are two methods of enhancing the image of the pupil; bright eye and dark eye effect. Optimally these two methods can be combined to allow all users, regardless of age, origin and eye colour, to be able to use an eye tracker.