Psychophysical effects and ergonomic risks of low‑frequency flicker in LED lighting

Artificial lighting flicker represents a significant yet often overlooked psychophysical stressor in workplace environments. In this scientific study, the flicker frequency of overhead LED lighting above a cashier’s workstation in a retail setting was analyzed. A high‑speed digital video recording was examined using a frame‑by‑frame method, revealing a dominant flicker frequency of approximately 3.6 Hz, which constitutes low‑frequency and highly perceptible flicker. This frequency range is known to induce visual fatigue, reduced concentration, irritation, headaches, and, in sensitive individuals, neurological responses. The scientific findings indicate that prolonged worker exposure to such visual stimuli may pose both ergonomic and psychophysical risks, particularly in occupations requiring continuous visual attention and direct interaction with customers. Comparison with relevant ergonomic and safety standards (IEEE) shows that this level of flicker exceeds the threshold of visual comfort and may adversely affect employee well‑being and work performance.