Investigating the Quantitative and Qualitative Status of Illumination and its Relationship with Mental and Psychological Health in office workplace: A Cross-Sectional Study

The development of new technology has changed the work environments of today´s world and made workers in these workplaces tolerate more visual and cognitive requirements compare with physical demands. This study aimed to investigate the quantitative and qualitative status of workplace illumination and its association with mental and psychological factors, such as visual fatigue, workload, and sleepiness, among computer operators.

A cross-sectional study was conducted on 120 computer operators from Tehran industries between October and December 2022. The HAGNER model EC1 lux meter was used to measure the amount and intensity of local illumination at the distance between the operator and the monitor screen and on the surface of the people's desks while considering the quality characteristics of the monitor and office rooms. A four-part questionnaire including demographic information and visual fatigue inventory, NASA Task Load Index (NASA-TLX), and Karolinska Sleepiness Scale (KSS) were developed to evaluate visual fatigue, workload, and sleepiness of individuals from the light conditions of the workplace, respectively. Data analysis was performed using SPSS software version 26 with a significance level of P <0. 05.

The average local illumination intensity at the level of studied workstation and computer were 199.80 ± 15.22 and 45.12 ± 5.85, respectively. There were significant associations between display screen illumination (p= 0.025), localized illumination level at work (p= 0.014), and type of light source (p<0.001) with visual fatigue, workload, and sleepiness, respectively. Moreover, the results of the Pearson correlation test showed that the visual fatigue scale had a significant and positive correlation with workload (r = 0.397, p = 0.002) and sleepiness (r = 0.295, p= 0.024).

Optimizing workplace illumination and computer levels can significantly improve psychological health by reducing visual fatigue, workload, and sleepiness risk factors. These findings highlight the importance of providing optimal lighting conditions in the office workplace in terms of quality and quantity to improve the psychological health and well-being of office workers.