Construction of a practical mental fatigue assessment model that is beyond the framework of fatigue induction models in laboratory environments: ZEN EYE Pro

This study presents ZEN EYE Pro, a VR-based system designed for assessing mental fatigue in real world environments.In just one minute VR viewing conducted with 61 healthy adults, the fatigue indexcalculated from the proportion of fixations directed toward negative paintings-showed a population mean of 44.20% ± 9.93%.The system further demonstrated ecological validity by detecting significant fatigue reduction following two validated interventions: a five minute mindfulness session (-18.85%) and a two minute aromatherapy session (-14.47%).Furthermore, to enhance scoring precision, blink behavior data from 982 users were analyzed.Notably, the data suggested a possible bi-phasic tendency in blink duration, with increases observed both in the low fatigue group-potentially reflecting slow spontaneous blinksand in the high fatigue group, which may be associated with cognitive vigilance deterioration.These findings indicate that VR-based oculomotor metrics provide an objective and ecologically valid indicator of mental fatigue.Moreover, integrating gaze and blink features into AI-based, state-dependent models has the potential to further improve accuracy and support scalable deployment across sports, workplace, and healthcare domains.