Eye-tracking is a state of the art process which tracks users' eye movements. In other words, it's a process of measuring eyes position over time, so measuring where someone was looking (where was his/her gaze point) and for how long. A device or software that makes those measurements is called an eye-tracker.
There are several techniques used in eye-tracking studies. Nowadays, the most popular and widely used are video-based solutions, where a webcam records eye movement, but it's always good to know the alternative methods.
Special contact lenses with a mirror or magnetic field sensor. When the eye moves, the lens moves with it, which causes signal changes, i.e., changes in the intensity of the magnetic field. By measuring changes in this signal, we can obtain data about eye movement.
Khaldi, A., Daniel, E., Massin, L. et al. A laser emitting contact lens for eye tracking. Sci Rep 10, 14804 (2020). https://doi.org/10.1038/s41598-020-71233-1
This methodology is based on two pairs of electrodes placed on the skin around the eyes. Two dipoles, negative at the retina and positive at the cornea, generate an electric potential. During the eye movement from the center towards the periphery position, the retina approaches one electrode and the cornea approaches the opposing one. This causes changes in the potential fields that can be translated to eye movements.
Light (usually infrared) falls on the eye's surface, where it is reflected. Then an optical sensor (i.e. a camera) detects the reflected light and analyze it to extract eye rotation from changes in reflections. These solutions usually use the corneal reflection and the center of the pupil to create a vector that indicates eye movements over time.
By Z22. Derivative work of the above file created by Björn Markmann. - File:Auge iris braun brown eye human menschlich Bjoern markmann.JPG and Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=38803307
The optical eye-trackers can be divided into:
Tobii Pro 3 Glassess https://www.tobiipro.com/product-listing/tobii-pro-glasses-3/
Instead of using infrared light, a commonly used webcam analyzes the participant's eyes image to detect the position of eyes and pupils (it requires calibration at the beginning where the system learns how the participant's eyes look like while watching certain parts of the screen).
Eye-tracking makes it possible to track people’s subconscious behavior. It’s commonly used in cognitive psychology, neuroscience (including neuromarketing studies for shelf testing and package design), or graphic design. It allows to track where people look, for how long, how fast they notice things, and in what order.
"Webcam-based eye-tracking has vast potential within market research and RealEye made a great effort customizing their solutions to our needs. We succeeded in having live online interviews with eye-tracking included and we look forward to build on this pilot study to take further advantage of this solution in future research."
"I'm really impressed with what Adam has created with RealEye. It's astounding how easy and fast it is to track and report on eye movement for a page or design."
For in-depth analysis of webcam eye-tracking accuracy check the following articles:
Either your own or RealEye participants. You can invite your users or panel and share the study with them using a participation link. All they need to have is a laptop/PC with a webcam.
We also have a network of panelists from all around the world - mainly from the UK and the US. Randomly picked users can be assigned to your task. They are called RealEye participants. We will not show them your stimuli before the test starts, so their interaction will be natural.
Note: RealEye participants can't take part in a 'Live Website' studies and studies longer than 10 minutes. Read more about the limitations here.