Corneal Reflection

The key measurement is the changing spatial relationship between the corneal reflection and the pupil. As the eye rotates, that relationship changes, allowing the recording system to estimate eye orientation and infer gaze direction. This reference supports noninvasive measurement during visual tasks and natural interactions with visual environments.

It provides an optical feature associated with the light source’s image on the eye’s curved, transparent surface. Recording this feature alongside the pupil gives the system two visual references whose relative positions can be compared. That comparison turns changes in eye orientation into a measurable basis for estimating gaze during behavioral experiments.

Sequences of estimated gaze positions can be examined as behavioral patterns rather than isolated locations. Researchers can identify fixations, saccades, and scan paths, then relate them to the visual task being performed. In reading or scene viewing, these measures provide objective evidence about how attention is distributed across a visual environment.

First, a camera records the light-source reflection and the pupil while a person performs a visual task. The recorded positions are then compared, with their relative changes used to estimate eye orientation and gaze. This workflow converts visible eye features into quantitative behavioral measures without direct physical contact with the eye.

During reading, measurements can characterize where fixations occur and how saccades move attention through text. During scene viewing, scan paths and visual attention patterns can be quantified across the viewed material. These outputs let behavioral researchers compare how people inspect different visual stimuli while relating gaze behavior to the task context.

Because gaze can be measured objectively while participants interact with visual environments, the method connects observable eye movements with broader behavioral processes. Fixations, saccades, and scan paths offer measurable indicators of visual attention during tasks, helping researchers analyze how perception and decision-making unfold in relation to what people view.