Impact of ipRGC-influenced lighting metrics on sleep, alertness and mood in university students: A field study using wearable sensors

This paper presents a field-based method for assessing personal light exposure using wearable spectral light sensors under real-world conditions. The method calculates melanopic irradiance and melanopic equivalent daylight illuminance from continuous spectral measurements and evaluates these measures in relation to self-reported sleep, alertness and mood data collected during daily life. The approach is demonstrated using one-week monitoring data collected from 50 university students and is evaluated against commonly used circadian lighting metrics, including WELL, Brown et al. recommendations and non-visual direct response. Results showed that participants frequently did not meet the recommended thresholds, while continuous melanopic exposure was associated with sleep and alertness. These results highlight the complementary value of continuous personal monitoring and the need for controlled studies to test the effects of meeting the recommendations.