An area of occupational safety and health that affects employees in almost all business sectors these days is that related to the use of computers, where cumulative trauma injuries are common.
Computer-related injuries and health problems are less dramatic than injuries caused by machinery in factories or falls from heights in the construction industry, but they can be debilitating and even disabling.
The key to preventing or minimising the likelihood of computer-related injuries lies largely in educating computer users on steps they can take to reduce the likelihood of such injuries, such as positioning the monitor and keyboard correctly and adjusting their own posture to minimise the danger of muscle or tendon inflammation.
Many of the injuries occur due to prolonged static positions or repetitious movements. Repetitive strain injury is one of the commonest types of injuries related to computer use. The term is applied to a work-related upper limb disorder to describe the pain from muscles, nerves and tendons caused by repetitive movement and over-use.
Working on a computer for long periods of time can cause inflammation of tendons, nerve sheaths and ligaments and damage to soft body tissues. Depending on the individual’s sensitivity to the repeated movements involved in using a keyboard, the cumulative effect of these repeated movements can be disabling.
Some of the cumulative trauma disorders (CTDs) affecting the forearm and wrist are carpal tunnel syndrome, tenosynovitis, epicondyliis, tendinitis and ganglion cysts.
Some of the symptoms of a CTD are pain, numbness, tingling or weakness in muscles or in an arm, hand or finger movements.
There are ways of using a computer that reduce the risk of CTDs. Computer users would be wise to adopt them.
In using the keyboard the wrist should be kept straight or in a neutral position. To achieve that the keyboard needs to be positioned so that the arms bend at approximately 90 degrees. Any bending of the wrist narrows the space available for the tendon and nerves, putting pressure on them, at the same time they are being required to work. One should avoid resting the wrist or forearm on a hard service while typing on the keyboard. If a wrist rest is used it should be well padded and replaced when it begins to lose its cushioning. The correct positioning of the computer monitor and mouse and any paper document you may be copying from can reduce the likelihood of neck and shoulder pain or stiffness.
If they are not positioned correctly, the neck and shoulder muscles are constantly working to keep the head and arms in an awkward position. Cradling the phone to one’s ear while typing can also contribute to neck and shoulder pain.
Ideally, the computer user’s line of vision should hit the top of the monitor. The mouse should be next to the keyboard at the same height. A document holder should be used and placed so that the document is at the same distance and height as the monitor. The computer equipment should be arranged in a straight line, so that the user is not twisting his back.
The chair that is used is important too, since sitting on a chair that does not provide support for the lower back can result in back pain. If there is no lumbar support, back muscles experience fatigue. An unsuitable chair also contributes to poor posture, such as slouching, that puts pressure on the spine. The best chair is one that provides lumbar support, is adjustable and allows the user to move the seat up and down, the arm rests in and out and the back of the seat forward and back. The chair should be adjusted so that the user’s feet can be placed squarely on the floor or on a footrest.
Prolonged use of computers can also cause eye strain, eye fatigue, eye irritation and blurred vision. There are simple ways to overcome this.
To reduce glare the monitor screen can be tilted down slightly, so overhead lighting does not hit the screen. Placing the monitor at right angles to windows should prevent glare from the window hitting the screen or the user’s eyes. Reducing room lighting to half normal office levels and using task lights for paperwork may also be useful.
These measures may be adequate without having to fit glare screens, which collect dust and need continual cleaning.
Working with a light screen background with dark type or images on a white or pale background are easiest on the eyes.
If the screen is flickering or characters are small and illegible, the computer may not be operating properly or the screen and characters may not be big enough to read comfortably. Prolonged viewing of the monitor can cause flickering sensations.
It is a good idea to take breaks by looking away from the screen for 10 seconds and standing up every 30 minutes or so to do other work, such as making phone calls or dealing with paperwork, to give the eyes a rest. Looking out of the window to prevent eye fatigue due to monotony is strongly encouraged.
Stopping computer work for 30 seconds to stretch and breathe deeply, while closing the eyes, can be effective and improve concentration and productivity.
Computers and desk areas should be kept clean to keep dust levels down and help reduce eye irritation. Blinking helps keep the eyes lubricated. Drinking plenty of water throughout the day can also help.
Talking Social Security is published weekly by the National Social Security Authority as a public service. There is also a weekly radio programme, PaMhepo neNssa/Emoyeni le NSSA, discussing social security issues at 6.50 pm every Thursday on Radio Zimbabwe. Readers can e-mail issues they would like dealt with in this column to email@example.com or text them to 0772 307 913. Those with individual queries should contact their local NSSA office or telephone NSSA on (04) 706517-8 or 706523 5.