Video Display Terminals (VDT) and Eye Health

VIDEO DISPLAY TERMINALS(VDT)AND EYE HEALTH

The RANZCO endorses the following statement made by the Americian Academy of Ophthalmology.

Based on available scientific evidence, the American Academy of Ophthalmology considers video display terminals (VDTs) to be safe for normal use and to present no hazard to the eye. There is no convincing experimental or epidemiologic evidence that exposure to VDTs results in cataracts or any other organic damage to the eye.

BACKGROUND

Mankind is constantly exposed to a spectrum of electromagnetic waves ranging from ultraviolet (UV) through the visible to the infrared and microwave regions. Any type of natural or man-made electromagnetic radiation is potentially hazardous if raditation levels are too high. This is why extensive studies over the past decades have established maximum permissible exposure levels for each type of radiation, including UV and X-ray.

Questions have arisen regarding the safety and comfort of VDT use. Tests indicate that radiation levels produced by VDTs are well below maximum permissible exposure levels. However, extensive or improper use of VDTs can result in discomfort and fatigue. These latter problems can be solved by addressing their primary sources: improper workspace design, improper job design, improper VDT design, and improper visual correction for VDT operators.

EVALUATION

A number of studies have been made by scientists at the Food and Drug Administration (FDA) Centre for Radiological Health and Devices, Bell Laboratories, and NIOSH.1-3 The data from their work indicates that the VDTs "emit little or no harmful ionizing (e.g., x-rays) or nonionizing (e.g., U.V) radiation under normal operating conditions.1 The emissions that were detectable were all well below the current national and international safety standards. In fact, the amount of ultraviolet radiation produced by VDTs is a small fraction of that produced by fluorescent lighting, and no X-rays at all were detectable.

As for ocular damage, the best available current experimental and epidemiologic evidence does not indicate (or demonstrate) that the level of radiation emitted by VDTs is capable of exerting any deleterious effects on the ocular lenses of people using terminals. Furthermore, the human cornea and lens serve as natural filters for UV radiation, thereby protecting the retina, which is sensitive to UV radiation.

Although there is no evidence that VDTs cause permanent ocular injury, in some work environments their use is associated with complaints of physical discomfort. These include ocular irritation (red, teary, or dry eyes), fatigue (tired, aching heaviness of the eyelids), difficulty focusing (blurriness for seeing near or far objects), headaches, backaches and other musculoskeletal discomfort. Studies indicate that most of these problems are related to poor ergonomic design of the workplace, lack of attention to the lighting and reflectance level 4 of work surfaces, the type and intensity of the job demands, and the quality of the video display. In addition, the power of reading or bifocal glasses may need to be adjusted for the working distance of the VDT.

CONCLUSION

Video display terminals do not cause permanent ocular damage, but the use of these terminals, often combined with a change in routine, may be associated with ocular and general musculosketetal discomfort. These can be alleviated by having the worker's reading glasses checked for proper working distance; by paying adequate attention to ergonomic factors, such as having seating and the angle of the VDT adjustable to each worker's comfort needs; by adjusting the lighting to minimise glare; by using high-quality monitors whose contrast and brightness can be controlled by the operator; by keeping the VDT screen clear of dust and by making provision for periodic rest breaks.

Any individual with eye symptoms related to VDT use should have a complete examination by an ophthalmologist, a medical eye doctor, who can diagnose whether the discomfort is due to simple eyestrain or whether unsuspected disease is present, and who can provide proper treatment.