Time-Dependent Recovery Dynamics of Visual Fatigue Under Blue Light Conditions: Insights to Dynamic Pupillometry

Computer Vision Syndrome, or Digital Eye Strain, is increasingly relevant to screen-intensive professions such as air traffic control. Visual fatigue, however, remains comparatively underexplored relative to cognitive fatigue, and existing non-invasive measures are often subjective or oversimplified. This study assesses dynamic pupillometry as an objective measure of visual fatigue under varying blue-light exposures. Ten participants completed a simplified air traffic controller’s visual task under High Blue Light (HBL) and Reduced Blue Light (RBL) conditions of 3, 5 and 9 minutes. Constriction Velocity (CV), Maximum Constriction Velocity (MCV) and Dilation Velocity (DV) were obtained with the Neuroptics NPi-300. Recovery was measured at 0, 2 and 4 minutes post-exposure. Results revealed a main effect of recovery for ΔCV, ΔMCV and ΔDV, and a significant interaction between condition and recovery for ΔMCV and ΔDV. ΔDV was most responsive to blue-light variations, supporting dynamic pupillometry as an objective tool for assessing visual fatigue.