In some circumstances, extensive use of computers can result in health concerns related to vision and musculoskeletal problems. Problems associated with computer workstations are generally temporary and can often be solved using simple corrective measures. This guide briefly discusses these concerns and addresses administrative controls (i.e., proper computer set up, monitor positioning, rest breaks and project assignment) and engineering or ergonomic controls (i.e., furniture design, lighting, glare control, computer workstation configuration and layout).
Eyes and Vision
There are a number of symptoms that may be experienced by computer operators. These symptoms include: temporary visual fatigue, sore eyes, headaches etc. Medical evidence shows that using VDUs does not cause damage to eyes or eyesight, nor does it make existing defects worse. Eye complaints are often caused as a result of visual fatigue or glare.
Visual fatigue can be caused by:
- Staying in the same position and concentrating for a long time.
- Poor positioning of the VDU.
- Poor legibility of the screen or source documents.
- Poor lighting including glare and reflections.
- A drifting, flickering or jittering image on the screen.
Controls To Avoid Visual Fatigue:
- Exercise the eyes by periodically focusing on objects at varying distances
- Keep the screen and document holder at the same distance from the eyes
- Practice blinking regularly
- Adjust the screen height so that when seated the top line of the monitor is no higher than your eyes
- Adjust the brightness control for comfort
- Keep the screen clean
- Adjust the contrast control to make the characters distinct from the background
- Service or repair monitors that flicker or have inadequate clarity
Reflections and glare can cause discomfort for the employee by making it difficult to see the information on the VDU. VDUs should be positioned so that neither the screen nor the employee are facing a window. For greatest comfort the employee's line of vision should be parallel with the lines of the overhead light fittings. Where fluorescent lights are used they should ideally be fitted parallel to the sides of the VDU and not parallel to the screen face. VDUs should not be positioned directly under overhead lights. Windows should be fitted with suitable, adjustable blinds.
Eye and eyesight tests
Any employee who habitually uses a VDU as a significant part of normal work (e.g. > 1 continuous hour per day, every day) can arrange an eye and eyesight test with a local optician. The cost for such an examination can be recovered from your department, provided you give prior notice to your supervisor.
Guidelines on the use of VDUs are available here.
Musculoskeletal complaints eg. upper limb pains and discomfort, are usually the result of the following conditions:
- Maintaining an unnatural or unhealthy posture while using the computer
- Inadequate lower back support
- Static load placed on the body by sitting in the same position for an extended period of time (i.e., turning head to the side to view poorly placed document)
- An ergonomically poor workstation design
Control of Musculoskeletal Problems
The control of musculoskeletal problems can be accomplished by utilising the ergonomic potential of your work station. Furniture, unit design and proper technique often go hand-in-hand. The following are descriptions of desirable features for furnishings and equipment, their set-up, and the proper technique to be used with each item.The Screen
Should swivel and tilt easily and freely to suit the needs of the user. Should be at the same level and beside the document holder Should be no greater than 700 mm away from the user's faceThe Keyboard
Should be detachable and adjustable. Should be placed to allow the forearm to be parallel to the floor without raising the elbows Should allow the wrist to be in line with the forearm so the wrist is not flexed up or down Should allow approx. 2 inches of space to rest the wrist. Should have a matt surface, and legible keys with concave tops. Should be positioned so that the angle at the employee's elbow(when seated) between the forearm and upper arm is in the range of 70° to 90°.The Chair
Should be stable and allow the user freedom of movement and a comfortable position. Should be adjustable in height. Should have a backrest which is adjustable in height and tilt. A footrest should be provided to any user who requires one.The Work Desk
Should provide sufficient leg room Should allow for adjustable height Should have enough surface area to support the computer equipment and space for documents Should have a low reflectance surface. A stable adjustable document holder should be provided where necessary to minimise the need for uncomfortable head and eye movement.
The following tips may also help prevent musculoskeletal problems:
- Plan your work so that VDU work is interrupted periodically by breaks in VDU work or changes in activity
- Alternate work tasks
- Use a stretching routine to relax the body
- Keep the mouse at keyboard level
There is evidence that concerns about radiation emissions from VDUs and their possible effects on pregnant women are unfounded. According to the World Health Organisation: 'The levels of ionising and non-ionising electromagnetic radiation which are likely to be generated by VDUs are well below those set out in international recommendations for limiting risk to human health created by such emissions and does not consider such levels to pose a significant risk to health. No special protective measures are therefore needed to protect the health of people from this radiation.'
The computer workstation is obviously an essential tool in today's work force. Although visual or musculoskeletal problems can occur, it should be noted that with the proper equipment, unit design, technique and work practices these problems can be controlled. Take a few minutes to look at your work station and use the information provided in this guide. The effort will minimise the risk of visual and musculoskeletal problems, and put you in control of your computer work environment. The University Safety Officer or your Departmental Safety Officer may be consulted to give further advice or undertake an assessment of your computer workstation.
For any other queries please contact the Service Centre on SafetyOffice@tcd.ie or extension 4000.