I suspect that until recently, visual displays and computer equipment have been added to offices with little thought for the comfort of those having to operate them, or the health risks that could result, and this indifference or ignorance extends to home computers too. But things are changing. On January 1st 1993, a European Community directive came into effect which should help to protect employees throughout industry from the possible ill-effects of working at computer-based workstations. From that date it was the duty of every employer with staff using display screen equipment to become acquainted with the new directive, and to put its requirements into operation. Home users of computer screens and games systems would be well advised to take note of the requirements too!
The directive, formally known as 'The Health and Safety (Display Screen Equipment) Regulation 1992', is mainly designed to protect word processor operators who use computer-based systems regularly, but most of the directive's requirements are equally applicable to computers found in home surroundings, where screen characteristics, positioning, lighting and the ergonomics of the system (its physical qualities as related to the user) can all play a vital part in the comfort of those using the equipment.
A major factor - and one that is often overlooked - is the change in routine that can result from the introduction of new technology. Many business activities have become entirely dependent on the computer workstation, with the result that those doing continuous work - such as word processing or database entry - can be confined to their chairs performing the same physical movements and concentrating on the screen for hours on end. The directive is particularly aimed at protecting operators in these situations, and recommends that job structures should be reviewed to make sure that eyes, muscles and mental faculties are not over-taxed by continuous use, and that where possible, breaks and different activities away from the screen should be built into new job specifications.
The most common problems arising from continuous use of computer workstations are muscular aches and pains. These can be caused by bad posture when typing or operating, poor siting of equipment, or by the body having to make the same movements over and over again. In the latter case, serious disorders such as Repetitive Strain Injury (R.S.I.) and tenosynovitus (inflammation of the sheaths enclosing tendons in the wrist) can set in, causing pain, numbness, or tingling in the arms. These problems should be identified and treated as soon as possible, as they can give rise to permanent damage and loss of feeling, and even after treatment they are prone to reoccur.
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. (Normal televisions update their image at a rate of 50 Hz, which is tolerable for most people at a distance, but is generally found to be too slow for a display screen used at close quarters.) 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. All display screens that use a TV-style tube emit small quantities of electromagnetic radiation - colour screens are usually worse than monochrome for this - but there is still no conclusive proof about the possible long-term effects of this radiation on users of the equipment, or those sitting nearby (as the strongest emissions are to the back and sides of the display screens). Despite public concern about the possibility of miscarriage and birth defects among some groups of visual display workers, and the much lower radiation figures felt to be acceptable in countries such as Sweden, the EC directive states that:
"in the light of scientific evidence pregnant women do not need to stop working with VDUs. 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."
The London-based VDU Worker's Rights Campaign, who have been working on VDU safety for some time, hold a somewhat different view: that the issue should be a cause for concern until there is conclusive proof one way or the other.
Music Video for "The Beauty Within" by Symbiosis (from The Comfort Zone and Amber and Jade)
There are now many display CRT screens which comply with the directive. PC users have a good choice of displays with anti-reflective glass, front-mounted controls, low emissions and tilt and swivel bases from manufacturers such as NEC, Taxan, Radius and Eizo. Many are 'Multisync' models - ie they can work at a variety of screen refresh rates - and can also be used with Apple Macintosh and PowerPC computers which form the heart of many desktop publishing systems. (Apple themselves quickly brought all their displays into line with current trends for safety and ecological thinking.) Good monochrome displays can be slightly sharper than colour ones but obviously fail to make use of the colour visual signals which make today's software easier to use. Finally, screens with a high refresh rate are less likely to cause visual disturbances. (Update 2006: Most TFT 'flat' screens now offer lower emissions, increased sharpness and high refresh rates, but sometimes at the expense of pixel size. To aviod eye strain try to use one with a large pixel pitch - as found on many 15 and 19 inch designs - and ideally choose a screen which offers adjustable height and screen viewing angle. Screens fed with a digital 'DVI' output can give a sharper image than those connected an analogue 'VGA' signal.)
Whatever you decide to do about your display screen equipment, the important thing about the final implementation of the new directive is that it should increase awareness among both employees and management about the problems that new technology can bring if care is not taken with its introduction. We can all benefit from safer working conditions as a result and hopefully, in the future, standards can be improved even further in both home and office from this starting point.
* Employers must analyse workstations to assess health and safety risks to users including physical problems, visual fatigue and mental stress.
* Risks identified must be remedied as quickly as possible.
* The assessment should be reviewed if software, hardware, furniture, lighting or the task is modified.
* Proper training must be given to users on health and safety and use of software.
* Employers must plan the activities of users so that their daily work on display screens is periodically interrupted by breaks or changes of activity.
* Employees are entitled to eyesight tests at regular intervals, or at their own request.
* Screen displays shall show clear characters with adequate spacing.
* The screen image shall be stable, with no flickering, and the brightness and contrast shall be easily adjustable.
* The screen must tilt and swivel to suit the needs of the operator, and shall be free of reflected glare.
* The keyboard shall be tiltable, and separate from the screen, allowing a comfortable working position, avoiding fatigue in the arms or hands.
* The work chair shall be stable, with height adjustment, and the seat back shall be adjustable in both height and tilt.
* Workstation and workplace layout shall be planned to prevent possible disturbing glare and reflections on the screen.
* The workstation shall be designed to provide sufficient space for the operator to change position and vary movements.
* Workstations shall be so designed that sources of light such as windows and other openings cause no direct glare on the screen, and no distracting reflections in it.
* Windows shall be fitted with an adjustable covering to attenuate daylight that falls on the workstation.
* Software must be suitable for the task.
from HMSO or booksellers.
The shorter booklet "Working with VDUs" is available free from the Health & Safety Executive's Freeleaflet Line: Fax 01142 892333
"VDU Hazards Factpack" and R.S.I. booklet, £4.00 each from:
The VDU Workers Rights Campaign, City Centre, 32/35 Featherstone Street, London EC1Y 8QX. 020 7608 1338
VDU Work and the Hazards to Health
(First published: LINE UP Magazine - The Journal of the Institute of Broadcast Sound, February/March 1993 - www.ibs.org.uk)
Sponsored by Clive Williamson's ambient group SYMBIOSIS:Music Video for "The Beauty Within" by Symbiosis (from The Comfort Zone and Amber and Jade)