Neon Pupillometry Test Report

Pupillometry, the quantitative study of pupil size and its changes over time, is an increasingly popular research tool. It furnishes non-invasive means for probing from low-level physiological reflexes to high-level cognitive processes. Neon, the latest head-mounted eye-tracking system by Pupil Labs, measures pupil diameter in physical units of millimeters without the need for a complex technical setup or time-consuming user calibration. In this white paper, we provide a comprehensive assessment of Neon's pupillometry feature. Through a combination of experimentation and computational modeling, we demonstrate that Neon provides pupil-size measurements that are independent of gaze angle and robust to slippage, i.e., variations in the positioning of Neon relative to the wearer's head. Neon's capabilities are further showcased by replication of three experimental findings from pupillometry research. More specifically, we quantify both the statistics of spontaneous and light-evoked pupil-size dynamics, as well as correlate modulations of pupil size with task-induced cognitive load. Taken together, our results affirm Neon as a versatile and reliable measurement device, enabling pupillometry studies in controlled laboratory conditions as well as highly dynamic naturalistic environments.