The incidence of visual fatigue was investigated in a group of clerical workers whose jobs required the use of visual display terminals (VDTs) for varying proportions of their workdays. Assessment techniques included: optometric screening, checklist for mood state and physical symptoms, and non-directive interviewing. Results indicate a relatively high incidence of visual fatigue and other visual complaints, but these tended not to be related to job pressure and hostility towards office computerization. There were no significant optometric effects.