Other physical effects from using workstations are mostly sight-related. Eyes can become fatigued if they have to stare at a display screen for hours on end, especially if the screen is much darker or lighter than its surroundings, or gives a fuzzy or jittery image, or is marred by reflections in it. Some people can be upset by the flicker of the screen, and are sensitive to any display with a relatively slow refresh rate. This flicker can cause headaches or trigger migraines, as can a slower kind that results from interference between fluorescent lights and display screen equipment, where the two are operating at different rates. Additionally, the field of static electricity emitted by older colour tubes in VDUs can be disturbing.
Some people experience dry itchy eyes, and contact lens wearers are particularly prone to problems.
Finally, stress can result from overly-demanding work patterns that arise from the unchecked introduction of new equipment, and can also be caused by trying to use software or hardware that is constantly going wrong, or is poorly designed for the job. One issue on which the directive takes a surprising stand is that of radiation. However, to avoid stress and anxiety, women working with VDUs should be given the opportunity to discuss their concerns with someone adequately informed of current authoritative scientific information and advice. Any workstation bought for office use after the beginning of 1993 must have complied with the new regulations, and employers must bring existing equipment into line with the directive by 31st December 1996. All the other recommendations in the directive applied immediately, and any display screen user who feels that their employer is not doing enough can take the matter up with their local Environmental Health officer.