Do video display units cause visual problems? - a bedside story about the processes of public health decision-making.
PURPOSE: Since the 1980s, it has been common for employers to provide eyesight testing for operators of screen-based equipment (SBE). This practice arose because many SBE operators reported symptoms of visual discomfort at work and there was apprehension that radiation emitted by SBE might be harmful to vision. Visual screening of SBE operators has been encouraged by government guidelines and in some countries, is required by legislation. This paper questions whether this practice should continue. METHOD AND RESULTS: A review of the literature shows: 1. SBE does not emit radiation in sufficient quantity to be harmful and there is no credible epidemiological evidence that work with SBE will damage the eyes; 2. SBE operators often report symptoms of visual discomfort but office workers who do not use SBE also report visual symptoms with the same or slightly lower frequency; 3. about 20 per cent of office workers have some uncorrected defect of vision that can contribute to the occurrence of visual discomfort at work and optometric intervention to correct these defects does reduce the occurrence of visual symptoms. However, defects of vision are not the only cause of visual symptoms at work. Other contributing factors are poor workplace ergonomics and psychosocial stress arising from poor work systems or poor inter-personal relationships at work. CONCLUSIONS: There is no compelling public health justification for requiring vision screening of SBE operators but it could be introduced as one element of a more comprehensive strategy to enhance visual comfort at work. If it is introduced, it should be for all employees engaged in visually demanding tasks, not just SBE users. An alternative to eyesight testing of employees is to encourage but not require employees to obtain eye care privately on their own initiative. This option has the advantage of restoring autonomy to employees to arrange their own eye care. Eyesight testing of employees in vision-critical occupations should be undertaken to ensure safety. In occupations in which there is a risk of eye injury, vision screening should be undertaken to provide a pre-injury record of vision.