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Computing Health and Safety

Computing Health and Safety
(Incorporating the UK Display Screen Equipment Regulations)
Key Topics: Disorders Regulation Risk Assessments Workstation Requirements Info Diagram Eye Tests
The long-term use of computers has been linked to a range of potential health problems, or
"computing related disorders" (CRDs). This section outlines these potential health risks and
provides an overview of the UK Display Screen Equipment Regulations 1992, and which
implement in UK law European Union Directive 90/270/EEC.
For an alternative brief summary of information on this area, please see the UK Health and
Safety Executive's booklet Working with VDUs. Or for an overview you can watch the
following ExplainingComputers video:
Over the past twenty years a great many questions have arisen concerning the links that
may exist between the use of computers and the health and safety of those who use them.
Some health effects -- such as joint pain and eye strain following an extended period
huddled typing at a screen and keyboard -- are recognised as an actuality by many.
However, proving with any degree of certainly the longer-term health impacts of computer
use remains problematic. Not least this is because widespread computer use is still a
relatively modern phenomenon, with the boundaries between computers and other
electronic devices also continuing to blur.
Current UK legislation, for example, makes it clear that use of a computer should not induce
a fit in an epileptic. However, given that it is also accepted in the UK that watching flashing
video images on a television can induce such a fit, it becomes immediately obvious that
both current guidance and legislation are inadequate. The existing Display Screen
Equipment Regulations 1992 were written at a time when viewing a photograph -- let alone
a movie or TV programme -- on a computer was not possible. At the time, any health risks
associated with mobile phones or wireless computer networks were also yet to be aired.
Hence, whilst the following does report the current legislation and guidance in respect of the
use of computer equipment, its historical context also needs to be remembered.
The health problems most highly associated with the use of computer equipment are upper
limb disorders, eye problems, stress and fatigue, and skin complaints. Upper limb
disorders is a term used to describe a range of conditions affecting the fingers, hands,
arms and shoulders. Such conditions may range from mild aches and pains, through to
chronic tissue and/or muscular complaints. Repetitive strain injury (RSI) is one such
condition. This is attributed to the excessive performance of repetitive, dextrous operations.
As a result of such repetitive activity, tenosynovitis (swollen muscles) or carpal tunnel
syndrome (swollen tendons) may develop.
Repetitive strain injury can result from prolonged high-speed typing, intensive use of a
mouse, or indeed the long-term use of a computer gaming control pad. Early signs of
repetitive strain injury include a tingling or numbness in the finger or fingers impacted, and
pain or even swelling across the hands and even upper arms. In the United States, the
National Institute of Occupational Health has reported that 40 per cent of people working
predominantly with computers suffer some RSI symptoms, with over ten per cent
experiencing constant discomfort.
The potential for RSI to develop or to be further inflamed can fairly easily be reduced by
varying work patterns to provide breaks for those involved in constant typing. Adopting a
range of postures across the working day can also help to reduce potential long-term
musculoskeletal problems, and as can be associated with the maintenance of a prolonged
static posture. Indeed, contrary to what much early workstation advice may have preached,
there is absolutely not one best position to adopt when using any form of computer
equipment long-term. You can find some tips for overcoming RSI in my Beating RSI video.
Whether or not eye problems result from short- or long-term computer use remains a
matter of debate. However, any form of excessive close work where the eyes are forced to
focus at a fairly fixed distance on a relatively bounded location is likely to cause at least
short-term eye strain and discomfort. This is simply because such activity is not what our
eyes were ever "intended" to do! Indeed, I remember once asking an optician if computer
use damages the eyes. In line with UK Government advice, he informed me that computer
use could not result in eye complaints. He then immediately advised me never to use a
computer continuously for more than an hour and a half!
Whilst the link between long-term eye problems is officially disputed (even if the practical
experiences of those who work on a computer all day suggests otherwise), short-term
computer related eye problems are undeniable. These tend to be associated with sore eyes,
headaches, blurred or softened vision, and sometimes a residual after-image experienced
for short periods.
As with the measures that can be taken to avoid repetitive strain injury, changes to work
patterns to allow breaks, as well as posture changes to avoid focusing from the same fixed
distance for very long periods, can be fairly effective in combating eye problems. Most
people also find that flat screen (TFT) displays tend to be more comfortable to use for long
periods. Large screens also tend to induce less eye strain than small displays, as they
encourage the user to look around the display (moving both their head and their eyes),
rather than just focusing continually on one location.
Many people find using a computer for long periods results in excessive stress and
fatigue. This can be as a result of the involved high levels of dextrous activity and visual
concentration. As already noted these are not a "natural" form of human activity, and hence
a potential source of stress. Some people also find computer use uncomfortable or annoying
when they are having to conform to software or hardware that constrains how they want to
get something done, or which constantly crashes or causes them to constantly wait for
actions to complete. Technology capable of doing the job can avoid the latter (if available!),
whilst a varied work routine with appropriate breaks is once again at least a partial answer.
Finally, a small number of people experience skin complaints associated with longer-term
computer use. Such conditions can include itching, rashes on the neck, face or hands, and
dry skin. Quite why this may be is again debated, though potentially skin complaints may be
a result of electrostatic discharges (created within laser printers and cathode ray tube (CRT)
display screens), and/or the dry air and static electricity that builds up in offices filled with
computer equipment. Appropriate ventilation is of course always a good idea and may
lessen the problem. The use of humidifiers and antistatic matting may also be of assistance.
However, many people apparently only even realise that computer use has been affecting
their skin following an extended vacation or change of job to a different working
According to current official UK medical research, the electromagnetic radiation emitted by
cathode ray tube computer monitors has no health implications, with no subsequently
related risks of increased miscarriages or birth defects being associated with visual display
unit usage by pregnant women. (This said, official guidance does suggest that pregnant
women anxious about computer use should be given the opportunity to voice their
concerns). In practice, most (if not all) CRT displays have not been replaced with flat TFT
screens, so at least removing the possibility of any CRT radiation risks to most users.
The first thing any UK employer needs to do in the area of computer-related health and
safety is to interpret the Display Screen Equipment Regulations 1992 within the context of
their own workplace and for those people who work for them. However, just deciding what
does or does not constitute a display screen equipment workstation can be problematic. For
example, devices mainly use to show television, video or film images are excluded, whilst
"portable computers" in prolonged use are not. The convergence of different types of
computer hardware can hence prove somewhat problematic in this respect.
Once it has been decided which individuals are using display screen equipment, an
organization needs to decide if such use is "habitual" and whether or not such individuals
are display screen equipment "users" or "operators". Users are defined as employees of the
company, whilst operators are defined as self employed people working on computer
equipment that the organization is providing for them. The distinction between users and
operators is significant in that not all employer responsibilities that apply to habitual display
screen users also apply to display screen equipment operators. Specifically, employers must
conduct workstation assessments, ensure workstations meet minimum requirements,
provide risk assessment information, and take risk reduction measures to ensure
workstations meet requirements for both users and operators. However, additional
responsibilities to provide health and safety training, eye tests and corrective appliances,
and activity change/break planning, only apply to habitual display screen equipment users.
The key issue for most companies, however, is in the identification of which of its workers
are "habitual" in their use of display screen equipment, and hence covered by the Display
Screen Equipment Regulations 1992. The Regulations distinguish habitual from non-habitual
users/operators because the chances of experiencing health hazards from workstation
usage are associated with the duration, intensity and frequency of such usage. However, it
is particular combinations of these factors that prove critical, with no hard-and-fast rules
existing for defining who will or will not be defined as a habitual user/operator. It is not
simply a matter, for example, of classifying workers based on their hourly workstation
Some workers -- for example secretaries, typists, date entry clerks and telesales operators - can easily be identified as habitual users (if employed by the company) or operators (if
self employed). In other cases, classifications can usually be made with reference to the
following questions:
Does the worker depend on the display screen equipment to do their job?
Does the worker have any discretion as to their use of display screen equipment?
Has the worker received significant training in the use of display screen equipment?
Does the worker normally use display screen equipment for an hour or more at a
Does the worker use display screen equipment more or less daily?
Is the rapid transfer of data between the worker and a screen an important job
Does the display screen equipment demand high levels of worker attention and
If the answer to most or all of the above questions is "yes", then the worker should be
classified as a display screen equipment user (if they are an employee) or as an operator (if
they are self employed but working at the client's location).
Under the UK Display Screen Equipment Regulations 1992 it is the responsibility of every
employer to carry out a "suitable and sufficient" analysis of every workstation they provide
for the use of habitual users or operators. It must be noted that such assessments need to
be made for each user/operator at each display screen equipment workstation they use
habitually. In a large office it is not, for example, sufficient to assess one of several hundred
identical workstations as the working conditions associated with them may differ depending
on the exact location of the unit, the individual user/operator concerned, and the work
being conducted.
It is also important to note that workstation risk assessments need to be reviewed if there is
any reason to suspect that they may no longer be valid. Triggers for such assessment
reviews may include hardware, software or furniture changes, workstation relocations,
substantial increases in the time spent using the workstation, changes in job requirements
(eg for increases in data entry accuracy or speed), or changes in lighting.
Within all companies in which display screen equipment is in use, at least one individual
should be given responsibility for computer-related health and safety. This person should
then be responsible for making workstation risk assessments, or else should delegate such
responsibility to another specific individual or individuals.
To be an effective workstation assessor requires a familiarity with the Regulations or a
summary thereof (such as provided on this page) and an awareness of the work being
conducted by each user/operator. Assessors must provide users/operators with appropriate
information (see below), make clear and signed records of their assessments and reviews
thereof, recognise their own limitations and draw on other expertise as necessary, and take
seriously all reports of user/operators complaints. Assessors must also be empowered to
ensure appropriate corrective measures as deemed necessary after assessments or reviews
thereof are undertaken, and to sanction reviews to ensure corrective measures are
A variety of workstation risk assessment checklists are available, such as this pdf from the
Risk assessments as above are fairly obviously intended to ensure that all display screen
equipment workstations meet legal health and safety requirements. These requirements
relate to the components of the workstation itself, the work environment, and the software
employed, as follows.
In terms of the workstation components, the requirements are that:
The image should be clear, stable and free from flicker.
Characters should be well-defined, clearly formed, of adequate size, and with
adequate spacing between lines.
There should be no glare or reflection on the screen likely to cause user/operator
There should be user/operator-adjustable brightness and contrast controls.
The display should be freely adjustable in terms of both tilt and swivel.
The keyboard should be tiltable and separate from the screen.
There should be sufficient space before the keyboard to support the wrists.
The keyboard should have a matt surface to avoid glare/reflection.
Keyboard legends should be legible with adequate contrast and definition.
Any document holder provided should be stable and adjustable.
The work chair should be stable, allow easy freedom of movement, and the
attainment of a conformable working position(s).
The work chair seat height should be adjustable.
The work chair back height and tilt should be adjustable.
A footrest should be provided for every user or operator who requests one
In terms of the broader work environment, the requirements are that:
There is sufficient space to work in a comfortable position, with opportunities for
varying movements and posture.
Lighting arrangements should be satisfactory and ensure an appropriate contrast
between the display screen and the background environment. Glare and reflections
(eg from windows) should be avoided, with blinds (preferably vertical) used to
prevent sunlight falling on display screens. Surfaces should have a matt finish to
avoid glare and reflections.
Noise levels created by workstation equipment should not be distracting to the
No item of workstation equipment should generate excess heat that could cause
user/operator discomfort. All electromagnetic radiation outside of the visible
spectrum should be screened to negligible levels (achieved by purchasing a flat
screen TFT monitor or an MRP II compliant CRT display).
In terms of software, the requirements are that:
The software must be suitable for the task in question.
Subject to appropriate training being provided, software must be easy to use and
adaptable to user/operator experience and knowledge.
No performance monitoring (such as measuring keystrokes per hour) should be
employed without the knowledge of the user/operator concerned.
The software must provide feedbacks to the user/operator on its status and
Appropriate ergonomic principles must have been employed in software design.
In practice, most of the above requirements will be met by purchasing modern
computer hardwareand software, and by installing it in a work location with adequate space
and where appropriate attention has been paid to lighting arrangements (including
measures to reduce screen glare and reflection). In many cases, the item of equipment
requiring most attention to meet the above requirements will be the adjustability or
otherwise of the user/operator's chair (with a great many cheaper office chairs not featuring
adjustable back height and tilt).
Risk reduction requires the identification of risks via appropriate assessments (as discussed
above), followed by appropriate action if necessary to ensure workstation compliance with
the requirements listed in the previous section. However, risk reduction also significantly
involves ensuring that users/operators are aware of possible risks that can result in
computing related disorders, and of the actions they need to take to avoid them. Risk
reduction and information provision therefore go hand-in-hand.
Appropriate information to provide to users/operators includes:
Adjusting the work chair to assume a comfortable working position with the forearms
roughly horizontal and the top of the screen at eye level.
Experimenting with workspace arrangements and ensuring that enough space is
In particular, placement of the screen to avoid glare and reflections (holding a mirror
in place of the screen is a good means of locating sources of glare and reflection).
Ensuring appropriate leg room and provision and use of a footrest if desired.
Using a soft touch when keying and keeping the wrists straight.
Provision and use of a wrist support if desired (with the gel variety being the most
Keeping the mouse or other pointing device within easy reach with the controlling
forearm supported.
Provision and use of an alternative pointing device (eg a tablet or touchscreen) if
mouse use is very intensive and/or becomes uncomfortable.
Keeping the screen clean (daily screen cleaning has been found to reduce eye strain
by as much as fifty per cent!)
Making changes to working position throughout the day, as well as planning and
taking breaks from display screen equipment activity.
Providing a copy of the Health and Safety Executive's booklet Working with VDUs is one
means of ensuring that users/operators have appropriate information on reducing the health
risks of using display screen equipment. The following diagram also provides a summary
(click the image for an enlargement).
The UK Display Screen Equipment Regulations 1992 require employers to plan working
routines so that a user's "daily work upon display screen equipment is periodically
interrupted by such breaks or changes of activity [so] as to reduce their workload at that
equipment". Ideally this should be achieved via a mix of screen-based and non-screen
based work. In practice today this can prove problematic now that many of the forms of
non-screen work referred to in the commentary to the Regulations (including filing and
handling mail) have since 1992 for many workers also become computer-based. Whilst
there is no requirement to plan breaks (as opposed to planning working routines), in
practice the planning of scheduled breaks is becoming more of a necessity for many
categories of display screen equipment user.
Guidance on breaks within the Regulations suggests that breaks should be taken before the
onset of fatigue, and that the number of breaks is more important than their duration. In
other words, many short breaks are far more effective than a few long breaks (and indeed
some researchers advise display screen equipment workers to close their eyes for 30
seconds every 15 minutes or so). If possible, breaks should also be taken away from the
workstation and spent on non-screen activities (as opposed to doing nothing). Finally,
breaks from display screen work should be included in work time.
It should also be noted that some display screen equipment workers (such as programmers
or graphic artists who may become overly-engrossed in their tasks) may need breaks
"imposed" on them, and that workers should not be allowed to forgo breaks from the
workstation in order to shorten their working day.
Under Regulation 5 of the UK Display Screen Equipment Regulations 1992, all employees
who are display screen equipment users have the right to request an appropriate eye and
eyesight test, which must be provided and paid for by their employer. Employees who are
due to become display screen equipment users also have this right.
In the UK, an "appropriate eye and eyesight test" means a "sight test" as defined in the
Optician's Act 1989, and will include an examination of the eye and a test of vision. The
British College of Optometrists have prepared a statement of good practice for optometrists
carrying out such tests for display screen equipment users.
Eye tests should also continue at "regular intervals" as clinical judgement considers
appropriate (and hence as dependent on the user's age, general health, eye health history
and eye health history of their family). Any visual difficulties -- most commonly excessive
eyestrain or focusing problems -- should also trigger an eye and eyesight test at the user's
Where required for display screen equipment work, users must be provided with "special
corrective appliances" (usually spectacles) at their employer's expense. However, it should
be noted that such appliances only need to be provided if the user's "normal corrective
appliances" cannot be used (as may be the case, for example, if a user wears bifocals that
prove impractical for display screen equipment usage). It should also be noted that the cost
of spectacles required for display screen equipment work is limited to the provision of basic
frames and lenses only!
In addition to risk reduction information (as above), which must be provided to both display
screen equipment users and operators, display screen equipment users or future users must
also be provided with appropriate display screen equipment health and safety training. Such
training needs to be suited to the tasks to be completed, and is usually incorporated into
other workstation equipment or upgrade training.
Training needs to include provision of all the risk reduction information (as above), plus
information on the channels of communicating to management any relevant problems or
concerns, the contents of the DSE Regulations, and the role of users in completing
workstation risk assessments.
Given the variety and intensity of computer usage in the modern world and workplace,
display screen equipment health and safety is a very significant issue. In some respects it
involves the application of common sense in ensuring that computer use is sustainably
comfortable and carried out under as close to optimal conditions as possible. However,
there are potentially also significant legal implications for employers who do not adequately
comply with the law.
Beyond the employer, taking all reasonable measures to avoid computer related disorders is
also of significant importance to individuals whether or not they are classed at work as
display screen equipment users. Relatively few people alive today have had more than
twenty years experience of working with computers, and nobody has spent an average full
working or domestic life interacting with digital technology to the extent that many people
now do every day. The long-term implications of computer usage on our health and welfare
-- physically, mentally and even socially -- cannot therefore yet be fully appreciated.
Regardless of any regulation, careful, limited and regularly-interrupted computer use is
therefore probably the best advice and practice for us all.