# Eye Tracking

> Using eye-tracking technology to measure where users look and for how long—revealing visual attention patterns invisible to observation.

*Tags: ux, research, mid-level*

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> [!info] Quick Definition
> Using eye-tracking technology to measure where users look and for how long—revealing visual attention patterns invisible to observation.


## What is Eye Tracking?

Eye-tracking technology uses infrared light and cameras to measure where a user's eyes fixate on a screen. The equipment records eye position 30-250 times per second. The result: a heatmap showing which areas attract attention and which are ignored.

Eye tracking removes guesswork. You don't assume users see the top-right corner; you measure it. You don't guess at attention patterns; you see exactly where eyes land and for how long.

**One sentence punch:** Eye tracking shows what users actually look at, not what you designed them to look at.**

## Why is it important?

- **Validates Visual Hierarchy:** You designed the logo to be prominent. Does the eye go there first? Eye tracking answers this.
- **Identifies Blind Spots:** Users ignore a banner you spent time on? Eye tracking reveals it. Designers often hide information in places users never look.
- **Measures Cognitive Load:** Higher cognitive load causes longer eye fixations. A poorly designed form shows long fixation times. A well-designed form shows quick scans.
- **Improves Accessibility:** Users with low vision struggle to find elements. Eye tracking reveals what's hard to locate visually. Design improvements follow.

## How Eye Tracking Works

1. **Equipment Setup** — Participant sits at a screen. Infrared cameras and lights track eye position relative to screen position. Modern eye trackers are non-invasive.
2. **Calibration** — User looks at specific points on screen. Equipment calibrates eye position to screen coordinates. Takes 30 seconds.
3. **Task Execution** — User performs tasks. Eye tracker records where eyes fixate, for how long, and in what sequence.
4. **Data Collection** — Heat maps show fixation patterns. Gaze plots show the exact sequence of eye movements. Timeline shows when fixations occurred.
5. **Analysis** — Compare designs. Which captures more attention? Which has longer fixation times? Patterns emerge.

## Eye Tracking Metrics

- **Fixation Duration** — How long did the eye pause in one location? Longer = more cognitive effort or interest.
- **Fixation Count** — How many times did the eye return to an area? Multiple returns = interest or confusion.
- **Time to First Fixation** — How quickly does the eye reach an area? Fast = prominent; slow = hidden.
- **Heatmap** — Overall visual attention pattern. Red = high attention; blue = low attention.

## Eye Tracking vs Observation

**Observation:** You watch a user and guess where they looked.

**Eye Tracking:** You measure exactly where they looked.

Observation is fast and cheap. Eye tracking is expensive but precise. Most teams use observation first, then eye tracking on critical interfaces.

## Mentor Tips

- **First tip: Eye tracking requires controlled conditions.** Head movement, lighting, and distance affect accuracy. Lab settings are best. Mobile eye tracking exists but is less precise.
- **Don't over-interpret fixations.** A long fixation could mean interest or confusion. Context matters. Combine eye tracking with interviews: "Why did you look at that so long?"
- **Test with real users.** Eye-tracking data from designers looking at designs is worthless. Only user data matters.
- **Use eye tracking strategically.** Eye tracking a checkout flow is valuable. Eye tracking every page burns budget. Focus on high-impact areas.

## Resources and Tools

- **Books:** "Eye Tracking in User Experience Design" by Aga Bojko, "Measuring the User Experience" by William Albert and Thomas Tullis
- **Tools:** Tobii Pro, SMI, Eyelink (eye trackers), UserTesting with eye tracking add-on, Validately
- **Articles:** Eye tracking guides on Nielsen Norman, visual attention research on [[UX Collective]]

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Source: https://www.fernandoux.com/en/wiki/research/eye-tracking/