An investigation of the influence of age on eye fatigue and hand operation performance in a virtual environment

Only a few studies in the literature have focused on the effects of age on fatigue susceptibility and hand operation performance in virtual environments, and even less research has been carried out focusing on older adults. This study aimed to assess the hand movement performance in a virtual environment with two group measures, including visual fatigue and depth perception. A total of 10 adults (5 young adults and 5 older adults) participated in this study. This study was conducted in the following order: pre-CFF measurement, performance of a Fitts’ Law task with stereoscopic viewing, post-CFF measurement every 10 min (during task), and recording of task movement time and error rate after each condition of the task. This study found significant effects of age and task index of difficulty on hand movement. Compared to the older adults, the young adults appeared to have better hand movement performance. Regarding eye fatigue, eye fatigue was significantly higher at binocular parallax of 9 cm than at 6 cm and 3 cm. Surprisingly, age had a significant effect on hand movement performance but not on visual fatigue. This study suggests that the operation time should be less than 20 min and that parallax should be 6 cm (visual angle = 1.38 degrees) to prevent visual fatigue when movement tasks are performed in a virtual environment. These data highlight the potential for age-related differences in hand movement performance during the performance of tasks in which fast and accurate selection are required in combination with the manipulation of 3D objects in a virtual environment, and the study provides directions for further exploration.