Objective evaluation of visual fatigue in VDU workers.

Prolonged work with visual display units (VDUs) may result in a wide range of subjective complaints of visual fatigue and somatic disorders. Accepted tests for measuring the physiological correlates of eye discomfort are lacking. In this study, we tested accommodation and convergence, which are most often linked experimentally with VDU work. The tests were carried out on 16 VDU and 13 control workers aged 24 to 43 years, before work at the beginning of the week (first examination) and again four days later at the end of the work day (second examination). The results in VDU workers showed that both accommodation and convergence range significantly decreased. In addition, those workers with powerful accommodative or convergence ranges at the initial examination had a higher decrease. We suggest that accommodation and convergence measurements can be used to evaluate visual fatigue objectively in VDU workers.