Abstract: Objective To investigate the preventive effect of desktop virtual monitors on digital eye fatigue caused by watching videos at close range. Design Crossover design experiment study. Participants 31 adult healthy subjects. Methods The subjects were randomly divided into two groups. The first group watched the same video for 10 minutes using a mobile phone and then a desktop virtual monitor, with a 30-minute break; the second group watched the same videos in reverse order. An open refractometer was used to record the diopter before, during and after watching the video, and the accommodative micro-fluctuation and accommodative error were calcuated. The data of the right eyes were used to analyse. The subjective visual fatigue score before and after watching the video was recorded using the Likert scale. Main Outcome Measures Diopter, accommodative micro-fluctuation, accommodative error and visual fatigue scale scores before and after watching videos. Results The diopter of the eyes using the mobile phone and using the desktop virtual monitor before watching the video was (-0.30±0.54) D and (-0.29±0.58) D, respectively (P=0.928). When watching the video for 5 minutes, the diopter of the eyes using mobile phone was (-3.32±0.68) D, which was significantly lower than that before watching the video (P=0.000); the diopter of the eyes using the desktop virtual monitor was(-0.39±0.63) D , which was not significantly different from that before watching the video(P=0.168); the accommodative micro-fluctuation of the mobile phone viewer and the desktop virtual monitor viewer was (0.33±0.10) D and (0.21±0.10) D, respectively (P=0.000); the accommodative error of the mobile phone viewer was lagging (0.25±0.68) D, and of the viewer using the desktop virtual monitor was leading (0.09±0.63) D (P=0.044). After watching the video, the diopter of the eyes using the mobile phone was (-0.53±0.56) D, which was significantly lower than that before viewing (P=0.000); the diopter of the eyes using the desktop virtual monitor was (0.34±0.61) D, which was no significant different compared with that before viewing (P=0.335). After watching the video, the visual fatigue scale score of the mobile phone viewers and the desktop virtual display viewers was increased (8.4±8.3) and (2.5±3.8), respectively (P=0.001). Conclusion Applying a desktop virtual display can prevent digital eye strain caused by watching videos at close range, which may be related to the lack of myopia adjustment during viewing. (Ophthalmol CHN, 2022, 31: 225-230)

Key words: digital eye strain, virtual reality