UXer’s Quick Guide to Eye Tracking

UXer’s Quick Guide to Eye Tracking

The benefits of classic usability testing methodologies — wireframing, prototyping, user interviews etc — are non-negotiable. But others are up for discussion — eye-tracking for example. Whether eye tracking has earned its place in the UX process has been debated back and forth for over a decade. Should you shouldn’t you?

Eye-tracking makes user testing less dependent on direct contact with the testers and therefore allows UXers to capture real physiological insights about their testers’ conscious as well as unconscious behaviors. But despite the user testing incentives, companies new to eye tracking should assess the benefit-cost ratio.

Read our quick guide and decide if eye-tracking is the next tool in your UX research kit.


What is eye tracking?

Eye tracking technology may sound like the vanguard of usability testing, but the methodology has actually been around for over 100 years, making the rounds in science, marketing and now usability studies.

In the late-1900s, Edmund Huey built a device to track eye movement in reading. Huey’s eye tracker used a contact lens connected to an aluminum pointer to track eye movement. This device helped him discover causes of fatigue and eye tension in reading, as well as raise questions related to reading fluency.

Obviously, eye-tracking techniques and applications have changed a little since then. Nowadays, eye-tracking software use infrared technology to measure the movement and dilation of a person’s pupils as they look at a screen. The data produced allows UX researchers to glean previously hidden insights into not just where study participants look, but what they’re thinking. Right now, when UX researchers reference eye-tracking, they’re referring to a usability testing technique that involves “measuring either where the eye is focused or the motion of the eye as an individual views a web page.”

Digging down into a little more detail, eye tracking experts work off moments of “fixation” and “saccades”

  • Fixation: the moment when a participant’s pupils lingers over a UI element long enough to process it
  • Saccade: the moment when a participant’s eye is in motion, roving over the interface without fixing on anything

So, fixation points are like stops on a subway and saccades are the short journeys between each stop.



What are the benefits to the UX process?

Eye tracking can provide you with information that is impossible to glean without the technology. Knowing rather than guessing exactly where people are looking when using your app or website is like gold to a UI designer, and UXers.

Eye-tracking gives you insights into sub-conscious movements and behaviors, and helps identify usability glitches that otherwise might have lain hidden. Including eye-tracking in a usability research study can help you figure out:

  • Whether participants are missing key UI elements — showing what things on the screen people didn’t look at
  • Which UI elements distract their attention, as an accompaniment to the concept of Fitts’ Law (object “weight” — in visual hierarchy — is a determining factor in what attracts eyes and mouse clicks)
  • Where problems lie
  • Which content attracts and which is unnecessary
  • How users accomplish goals


Analyzing the data

User testing with eye tracking software allows UXers to watch the live eye tracking stream provides during usability testing. This provides the testing team with a deeper understanding of behavioral patterns and therefore allows them to ask more relevant and personalized questions, for fuller insights into the user’s interaction.

So, why aren’t we all doing eye tracking already?

Before you all get too excited, we have to point out that eye-tracking does have its less awesome aspects.

First and foremost, it’s expensive. A professional eye-tracking system could cost you around $10,000, which is a big investment for something that is going to supplement, not replace, your current UX research tools.

Secondly, eye-tracking is hard to do right. Unlike many technologies such as real time streaming that have been effortlessly incorporated into user research studies, eye tracking requires special training, experience and a whole lot of analysis. Some user researchers introduce eye-tracking in good faith, then find they’re overwhelmed by the data and drop the technique.

Finally, while eye-tracking can reveal great insights, it can’t override human visual perception. Eye-tracking technology focuses on foveal vision (focused, central vision) and not peripheral vision, which accounts for 98% of our visual field. We still ‘see’ screen elements in our peripheral vision, but just don’t ‘look’ at them. Eye tracking data doesn’t take this into account.


Where eye-tracking fits into the UX process

If you and your UX team do decide to dabble in eye-tracking, take into account that you can’t just fire up an eye-tracking system and carry on as normal. Your UX research process will have to change to accommodate eye racking and ensure its effectiveness.

Eye tracking can be a great accompaniment to user testing, to identify how users are interacting with a UI. But remember that eye tracking isn’t a replacement for good, old-fashioned user testing to determine why users behave the way they do. The why data tells you what you need to adjust in your designs in order to improve the user experience.

Don’t skimp on the qualitative or quantitative testing. Integrating your usability studies with prototyping can save time and reduce the opportunity for errors further down the line in software development. You can easily incorporate your testing process at the start, middle and end of your project without risking timelines or blowing budgets. You can test your early concepts with low to mid-fidelity wireframes and then test the core usability with high-fidelity prototypes.


Tips to get started with eye tracking

If you are thinking about giving eye tracking a go, here’s our advice:

  • Expand your usability testing project’s scope. Eye tracking is a lengthy process. If you’re performing qualitative eye tracking tests and are going to manually review each recording, 5 testers will do the job. However, for other studies, such as heat maps, you’ll want to recruit at least 39 participants for a better range, according to Usability Geek.
  • Call in the experts. Eye tracking is expensive. Consider the equipment you’ll need to use and the time you’ll need to allocate to the initial training. If this isn’t viable but you’re still keen to try it out, why not get in touch with a consulting firm and get the experts to do the heavy lifting.
  • Get participants to go through tasks uninterrupted. Asking questions or talking out loud will skew eye tracking results.
  • Make sure participants stay within the monitor’s range. If they move out of it, step in and get them back within the monitor’s sight lines.



To eye track or not to eye track? Some of the industry’s foremost experts remain conflicted as to the value of eye tracking its value.

True, eye tracking can help to improve UX optimization as well as offer deeper insights into user behavior that can benefit your bottom line.

Nevertheless, eye tracking is certainly not a substitute for conventional UX research or usability studies. But if you’ve got the resources and time to give it a go, eye tracking can be a wonderful addition to testing, offering deeper insights into the user psyche.