Effects of simulated natural light brightness on visual perception in virtual reality forests: An eye-tracking study

Although natural light is essential for human health and well-being, the potential effects of different brightness levels of light on the visual perception of forests have not been discussed. Using controlled eye-tracking experiments, this study explored the impact of seven simulated natural brightness levels, from the darkest to the brightest, on the visual perception of 118 participants in a virtual reality (VR) forest environment. One of the most significant findings of this study was the marginal effect of natural light brightness levels on visual physiological stress in VR forests, with the pupillary unrest index decreasing significantly with the increase of natural light brightness; Secondly, the study analyzed the influence of natural light brightness levels in VR forests on the visual engagement behavior of eye tracking, that is, bright forest environments showed an overall trend associated with longer fixation duration, less saccade duration, and greater fixation direction ratio; Thirdly, in terms of visual perception evaluation, the study found an inverted U-shaped trend of mood, restorative perception, perceived safety, and natural light brightness level in VR forests. In addition, the study also found a significant correlation between visual physiological and psychological indicators in VR forest natural light visual perception experiments. These findings help us understand the visual perception effect of forest nature light exposure as a whole, and provided important clues and a basis for future research on improving the visual comfort of forest natural light.