safety issues by using computer

Advice on using your computer
Set up and connect your equipment in accordance with the instructions provided by the supplier or manufacturer. Always be sure that the computer is switched off and disconnected from the mains electrical supply when you connect or disconnect any of the electrical leads.

Working safely [top]
The use of visual display units (VDU) and other display screen equipment (DSE) has been related to various symptoms to do with sight and working posture. These symptoms are often perceived as fatigue of some kind. Applying simple ergonomic principles to the layout of your work area and how you study can readily prevent them.

Try to position the monitor to minimize glare and reflections on the screen. Suitable lighting is important: remember that glare can occur either directly or by reflection from the screen. Glare from windows can usually be eliminated by curtains or blinds, or by facing the screen in a different direction. It might be a good idea to make adjustments from time to time during the day, as light changes. You should have general lighting, by artificial or natural light or both, that illuminates the whole room adequately.

There is a very slight risk that a CD-ROM can break inside a CD-ROM drive. The reported risk is about 1 in 10,000 discs. A handful of cases, worldwide, have apparently occurred where plastic slivers have flown out of the drive with risk of injury. This seems to occur with the modern very high-speed CD-ROM drives (40x speed or faster) and when the plastic of the CD-ROM is cracked at the central rim (hub ring) or the disc or drive is unbalanced.

If you have a high-speed drive you are very strongly advised to check the hub ring of all CD-ROM discs for cracks before use. CD-ROMs that are off-balance and vibrate noisily in the drive may also be a risk.

This problem is not reported as affecting DVD-ROM drives.

If you have a CD-ROM drive that is very noisy with most CD-ROMs then you should take this up with your computer supplier. If you are concerned about cracks or vibration with any of the CD-ROMs supplied tn you by The Open University, please return it to the relevant warehouse for an exchange.

Eyes and eyesight [top]
There's no evidence that working with DSE is harmful to the eyes, nor that it makes visual problems worse, although a few people who have difficulties with their sight may become more aware of them. But working at a screen for a long time without a break can have effects similar to reading or writing uninterruptedly, and may make your eyes feel 'tired' or sore. You might find that it helps to look away from the screen from time to time and focus your eyes on a distant object.

Making yourself comfortable [top]
As for any task that means working in one position for some time, it's important to make yourself as comfortable as possible when you use your computer. Place the monitor in front of you and at a comfortable viewing distance. If you're working from a document you might find it better to have that directly in front of you and the screen to one side. Try to position the top of the monitor display slightly below eye level when you're sitting at the keyboard.
Before starting work you should:

* Adjust the positions of the screen, the keyboard, the mouse and the documents you're working from, so as to achieve the most comfortable arrangement. Make sure that you have space to use your mouse easily, and rest your wrists in front of the keyboard when not typing.
* Adjust the position of your chair to give you a comfortable viewing distance and posture. The screen should probably be somewhere between eighteen and thirty inches away from you, whatever suits you best.
* Good keyboard and mouse technique is important. Keep your upper body as relaxed as possible and don't over stretch your wrists and fingers. As a general guide, your forearms should be roughly horizontal and your elbows level with the keyboard or the mouse.
* If your feet don't reach the floor when you're sitting in a good position, try a footrest.
* Use a document holder when copying from a manuscript.

Take a break [top]
Whenever you can, try to arrange your study to consist of a combination of work on and away from the screen, to prevent fatigue and to vary visual and mental demands. Long spells of intensive screen work should be broken up by periods of non-intensive work of a different kind.
The nature of your study and the combination of media you're using will determine the length of break you need to prevent fatigue, but as a general rule:

* You should take breaks before the onset of fatigue, not in order to recuperate. The timing of the break is more important than its length.
* Short, frequent breaks are more satisfactory than occasional, longer breaks. A break of thirty seconds to two minutes after twenty or thirty minutes of continuous work with the screen and keyboard is likely to be more effective than a fifteen-minute break every two hours.
* If possible, you should take your breaks away from the screen, and avoid activities that require actions similar to your work (writing, crosswords or needlework, for example).