The 10 Most Used Eye Tracking Metrics and Terms
Eye tracking now shapes how websites are designed, ads are tested, and how reading and attention are studied. But the technology is only as useful as your ability to read its output. Raw gaze data is just a stream of coordinates; the metrics turn that stream into insight.
If you’re getting started with a Gazepoint system, here are the ten terms you’ll meet most often.
1. Fixation
A fixation is a moment when the eyes hold still on one point, usually for 150-300 milliseconds. This is when visual information is actually processed. Fixations are the building block for many other metrics. Gazepoint classifies the raw gaze stream into fixations automatically.
2. Saccade
A saccade is the rapid jump between fixations, one of the fastest movements the body makes. Vision is largely suppressed during it. Saccades show how gaze travels rather than where it lingers. Short, frequent ones suggest careful reading; long sweeps suggest searching or skimming.
3. Gaze Point
The gaze point is the basic output: the on-screen coordinates that the eyes are looking at. An eye gaze tracking will sample the gaze point many times per second. The Gazepoint GP3 captures these at 60 Hz, the Gazepoint GP3 HD at 150 Hz. A higher sampling rate gives finer timing, which matters for fast events like reading.
4. Heat Map (Attention Map)
A heat map overlays fixation data as color, with warm tones marking the areas that drew the most attention. It’s the most recognizable eye tracking visualization because anyone can read it at a glance. It shows how gaze points are distributed over the entire screen. Gazepoint’s tools generate heat maps and can combine multiple participants into one view, giving you valuable insight on which elements are gathering the most attention.
5. Area of Interest (AOI)
An AOI is a region you define on the stimulus, such as a logo, button, or headline, so metrics are calculated just for that region. AOIs let you ask precise questions, like whether people noticed the price before the buy button. Gazepoint Analysis supports dynamic AOIs that follow moving elements in video.
6. Time to First Fixation (TTFF)
TTFF measures how long it takes for a viewer to first look at an AOI after a stimulus appears. It’s a direct read on how quickly something grabs attention. A short TTFF means an element catches the eye early; a long one means it’s being overlooked. It’s a staple of ad and UX testing.
7. Dwell Time (Fixation Duration)
Where TTFF measures when attention arrives, dwell time measures how long it stays, summing every fixation inside an AOI. Longer dwell usually means more interest or more difficulty. Read alongside TTFF, it shows whether something was noticed late but studied closely, or seen instantly and dismissed.
8. Gaze Path (Scan Path)
A gaze path shows the sequence of fixations and the saccades linking them, usually as numbered dots joined by lines. Unlike a heat map, it preserves order and route, so you see the journey the eyes took. It’s invaluable for reading patterns, navigation flow, and visual hierarchy. Gazepoint Analysis renders fixation paths in its standard output.
9. Pupil Diameter (Pupillometry)
Pupil diameter is the pupil’s measured size over time. Beyond reacting to light, it shifts with cognitive load and arousal, making it a proxy for mental effort. The Gazepoint Biometrics System adds signals like heart rate and galvanic skin response, so you can seamlessly link pupil diameter with other biometrics metrics.
10. Fixation Count
Fixation counts and revisits on an area of interest reflect how thoroughly an element was inspected. High counts for revisits can mean engagement or confusion, and low counts can indicate low interest in the element.
Putting the Metrics to Work
No single metric tells the whole story. A heat map shows the what, a scan path the order, TTFF and dwell time the attention, and biometrics hint at the why. The skill is matching the metric to your question.
You don’t compute any of this by hand. The Gazepoint GP3 and GP3 HD eye trackers capture the data, and Gazepoint Analysis handles data processing and export. If you’re ready to turn gaze data into real insight, contact us to learn more!
