Health and Safety
– Visual Display Units
by Dr George Socrates
 
With the advent of the micro-electronics age, visual display units (VDUs) are now beginning to have a profound effect on work both and in the office and in industry. In the broad sense, a VDU may be thought of as a self-contained device for the projection of a picture or symbols using either a light beam or a screen such as those used in television (newer technology is changing the types of screen available). The latter (tv) is used in an electronic VDU which has, in addition, a keyboard linking the operator with a computer or some computerised machine. Although electronic VDU systems have (at the time this was written, 1979) been in use in the UK for some fifteen years, it is only recently with their increased use that concern regarding the safety and health of operators has been widely expressed.
 
The application of VDUs
    The operator uses the keyboard to control or 'interrogate' computer equipment. The tasks normally carried out using VDUs are:
  1. the entering of data into the computer

  2. the retrieval of information from the computer's databank

  3. the checking of information in the computer store against other records. Both the operator's instructions and the equipment's response are displayed on the screen.
Health and Safety
    As far as is known, there are no health hazards to operators who only make occasional use of VDUs. The health hazards are associayed with operators spending long periods of time with the VDU.
 
Fatigue – eyestrain
    The effect of concentrating on the screen for long periods has been found very tiring by many operators. Other complaints have been of headaches, back- and neck-aches, giddiness, nausea, irritability, anxiety and depression. In general these may be associated with the ergonomic design of some VDUs and unsuitable working conditions which aggravate matters.
    Eyestrain is probably the most serious problem which operators experience. Trouble normally arises if operators have frequently and rapidly refocus their eyes from the VDU screen on to some papers or an instrument in front of them to obtain data or perhaps to note down information from the VDU. Unfortunately also, many operators have visual defects which are not corrected sufficiently, if at all.
    Ideally, the vision of all VDU operators should be examined on starting the job and at regular intervals afterwards and the operators fitted with the correct spectacles. A reading correction for the viewing distance of the screen can be made although many VDUs have sufficient flexibility in the system to allow the operator to move the screen to a suitable distance. People who wear bifocal glasses generally need to hold their heads in a tiring position and are not suitable operators unless they are provided with the correct spectacles.
    The lighting of the area surrounding the VDU and the light emitted by the VDU screen are both of importance. In jobs requiring operators either to read or write down information in addition to looking at the screen, more light is required than for viewing the screen only. In fact, VDU operators who are required only to monitor the screen can work perfectly well in a dark room.
    Excessive glare from the surrounding environment can cause problems if, for example, the screen is opposite a window or some other light source. The colours of both the screen and the symbols can aid or hinder the good performance of the operator. For example, yellow symbols on a dark green background have been found restful to the human eye whereas other combinations, such as red and green, have been found unsuitable.
    Flickering of the image can cause not only eyestrain but also, in the case of some susceptible individuals, an epileptic fit. It is therefore important that the rate at which information on the screen is refreshed is kept high – of the order of 50Hz (well slow by 2001 standards). It must also be borne in mind that the quality of the picture decreases as the tube wears out and this may also result in eyestrain for the operator. Incessant flashing messages, for example, warnings that a simple programme error has been made, can be extremely tiring to the operator's eyes.
 
Radiation
    Although concern has been expressed regarding the emission of harmful radiation such as X-rays, infrared and ultraviolet light and microwaves, the results of many tests have shown that the emitted levels are extremely low. In fact, the Health and Safety Executive have issued a statement which indicates that VDUs do not present a hazard to operators due to ionising radiations.
 
Ergonomic aspects
    Undoubtedly, the ergonomic aspects of VDUs and their environment require very careful thought. Some of the important areas to which particular attention should be paid are as follows
  1. the standard of accomodation, including heating, lighting, ventilation, and noise (workink in a small or crowded room with no windows or air-conditioning will obviously result in problems.
  2. the layout and siting of the keyboard/
  3. the display – with regard to viewing distance, screen tilt, colours if image and background, contrast, display size and character clarity.
    It is best if, wherever practicable, the system is sufficiently flexible to give the opportunity for adjustment of these variables, for example, screen position and brightness.
    Apart from these ergonomic considerations, others relating to general safe working must not be forgotten, such as walkways, floor areas and working surfaces not being obstructed by trailing wires liable to trip up workers and operators not being presented with electrically-dangerous peices of wquipment due to badly-made electrical connections, perhaps resulting from makeshift arrangements. All VDU equipment must be properly maintained and any defects rectified immediately.
 
Unions' concern
Understandably, unions are concerned about the health of VDU operators, especially as more and more are being introduced. Most unions recommend a work schedule which allows the operator to take a break from the screen at regular intervals – two hours work followed by a thirty minute break is recommended. During the break, the operator can, of course carry out another job/task. It is considered that the short intervals during which the computer is searching for information, resulting in no fresh data being shown, do not give a sufficiently long break for the operator. Unions are demanding that the eyesight of VDU operators is checked regularly and that the working environment is made comfortable.
    There are obvious similarities between the viewing of a domestic television and the VDU screen. However, watching a television at home at least involves a freedom of choice in so far as it can always be switched off or the channel changed whereas operating a VDU at work does not have this element of choice.
 
Axiompc's comments:
    As I stated within the article, it was written in 1979. Many of the concerns have now, in 2001, been addressed and most companies operate to similar standards as those recommended within the article. My comments are related to the United Kingdom but hopefully hold true for the rest of the western world at least. If they do not apply, get things changed as your boss will get more out of you and, most likely, less staff off sick.
    I recalled and located this article and it was from the time I was gainfully employed as a Production Engineer and also involved in Work Study along with Organisation and Methods.

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