To investigate ocular fatigue after the use of a head-mounted display (HMD)-type virtual reality device. Methods

Healthy adult volunteers were examined for ocular fatigue before and after watching videos for 10 min with an HMD-type virtual reality device. Subjective ocular fatigue was measured using a questionnaire. Objective fatigue was measured using the critical flicker fusion frequency (CFF), high frequency component of accommodative microfluctuation, and accommodation amplitude. The accommodation amplitude was measured using the push-up method and the dynamic measurement mode of the autorefractometer. Changes in the spherical equivalent were also measured. Results

The questionnaire-based subjective ocular fatigue increased ( p = 0.020) after use of the HMD device. In the dominant eye, the high frequency component of accommodative microfluctuation increased ( p < 0.05). The accommodation amplitude using the push-up method was decreased in the nondominant eye ( p = 0.007), and temporary myopia was observed ( p < 0.05). However, there was no increase in ocular fatigue in the CFF or the accommodation amplitude using the dynamic measurement mode, which showed no significant difference before and after using the HMD device ( p > 0.05). Conclusions

A subjective test and some objective tests suggested that use of the HMD-type virtual reality display increased ocular fatigue. However, no increase in ocular fatigue was measured using CFF nor in the accommodation amplitude using the dynamic measurement mode which was a limitation of the study. More studies with the aim to alleviate ocular fatigue after using HMD-type virtual reality devices are therefore needed.