Abstract
There are few negative effects to make people discomfort using virtual reality systems. In this paper, we investigated the effects of visual fatigue when wearing head-mounted displays (HMD) and compared the results with those from the smartphones. Forty subjects were recruited and divided into two different groups. The visual fatigue scale was measured to assess the subjects' performance. The results indicated that visual fatigue caused by the conflict of focal distance and vergence distance was less severe than visual fatigue caused by long-term focus without accommodation.