Since the introduction of the Video Display Unit (VDU), investigations
have been conducted to determine what variables, if any, produce visu
al fatigue when using a VDU. Human factors researchers have typically
investigated relationships between VDU use and visual fatigue by havin
g users subjectively evaluate the extent of their fatigue with a self-
report questionnaire. This paper reviews four typical methods of gathe
ring self-report visual fatigue symptoms that appear within the human
factors literature.