Investigating the effect of luminosity and color temperature of light sources on the extent of mental and visual fatigue under experimental conditions

Abstract

Aim: Undesirable lighting can affect the visual system, as well as mental, neuropsychological, and physiological efficiency of staff. The present study was done to determine the effect of luminosity and nominal correlated color temperature (NCCT) on the extent of mental and visual fatigue under experimental conditions among students at Isfahan University of Medical Sciences. Materials and Methods: This experimental study was done in summer 2022 on 12 students at Isfahan University of Medical Sciences. To measure the mental fatigue, flicker fusion method, while for visual fatigue, Rajabi questionnaire was used. In this study, two lamps with NCCT 3000 K and 6000 K were used at three angles 15°, 30°, 45°. Results: The mean age of the subjects was 20.91 years. At both NCCT 6000 K and 3000 K, the maximum and minimum extent of visual fatigue occurred at angles 15° and 45°, while the maximum and minimum mental fatigue score happened at 45° and 15°, respectively. There was a statistically significant difference in the mean scores of mental fatigue (P < 0.001) and visual fatigue (P < 0.001) between 60000K and 300000K at 0.01 level. Conclusion: The NCCT and angle of the light source position can contribute to the development of mental and visual fatigue. Once the angle of radiation increased, the extent of mental and visual fatigue diminished. The extent of mental fatigue, as with visual fatigue, was greater at 3000 K compared to 6000 K.

Keywords

• asthenopia
• color temperature
• contrast sensitivity
• flicker fusion
• mental fatigue