The impact of the pupil size artifact on pupil-based eye-tracking data in reading tasks: Assessment and compensation.

ABSTRACT: Eye tracking in reading research requires high spatial accuracy due to small, densely arranged areas of interest. However, despite widespread use of pupil-based eye trackers in reading studies, a major source of systematic inaccuracy remains largely unaddressed: the pupil size artifact (PSA) - apparent gaze shift in fact caused by pupil dilation even when the eye remains stationary. Using pupillary light reflex manipulations and reading tasks under controlled luminance, we quantified gaze inaccuracy due to the PSA and compared correction methods. We observed systematic apparent gaze shift of up to 2 ∘ as pupil sizes varied from 2 to 6 mm. Horizontal PSA showed contralateral patterns (median slopes: 0.38 ∘ /mm), while vertical PSA increased with pupil size (up to 0.86 ∘ /mm for larger pupil

SUBMITTER: Culemann W 

PROVIDER: S-EPMC12717228 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature