Evaluating the Impact of Display Light Settings on Circadian Rhythms, Visual Fatigue, and Cognitive Performance: A Comparative Study of Static and Dynamic Backgrounds

As displays become ubiquitous and increasingly integrated into daily life, their impact on human health is a major concern for academia and industry. The aim of this study was to investigate the effect of display backgrounds with different Correlated Colour Temperature (CCT) and Circadian Stimulus (CS) settings on human circadian rhythms and visual fatigue. Twelve participants underwent four 9-hour display lighting interventions over a 10-day period, including S1 (CCT at 4000K; CS from 0.29 to 0.15), S2 (CS at 0.2; CCT from 6500K to 4000K), S3 (CCT from 6500K to 4000K; CS from 0.30 to 0.15), and static S4 (CCT at 4000K; CS at 0.2). Participants' melatonin levels, visual fatigue, cognitive performance, sleep quality and 24-hour core body temperature were monitored. The results showed that S4 was the most circadian-friendly condition, with the least visual fatigue and the best sleep quality. In addition, the S3 intervention resulted in the lowest nighttime alertness. Therefore, static display backgrounds with low CCT and CS appear to be more beneficial for circadian health than dynamic display backgrounds. Furthermore, the results of several statistical tests showed that CS has a greater effect on rhythm than CCT.