1. Make sure that you have sorted out your desk and chair (see Health Hazards on chairs and desks).
2. You also need to think about the whole environment, including lights, walls and windows, before starting the detailed adjustments.
3. It is also useful to understand the work your eyes have to do before thinking about positioning the monitor.

But ... if the machine is shared you will have to negotiate these system settings.

Your monitor should be about an arm's-length away (50-80 cm) in your normal sitting position. But it is safer to sit further away from a larger monitor or one where the data is designed to be much larger than normal text, for example for ticket clerks.

The best position is usually directly in front of you. Putting the monitor off-centre might cause muscle pain if you need to twist to view the screen. Some monitors are so deep there is no room on the desk for the keyboard. The newer, flat screens avoid this problem, as they can be placed almost flush with the wall.

But … if you use the screen for occasional reference or data input, other work would occupy the privileged position directly in front of you. A swivel chair or movable monitor might be a better solution.

The top of your screen should be level with your eyes. This way your neck muscles are relaxed and your eyes can scan the data on the screen. You should not need to move your head up or down, or from side to side to examine the whole screen. Old phone books are useful for raising the monitor to eye level as few monitors are supplied with height adjusters.

But … if you use a large monitor the eye-line might be below the top of the screen (5cm or 2inches).  If you have to wear multi-focal lens while using your computer, the screen will probably have to be lower in any case, but such glasses are best avoided for prolonged work at the computer.

The screen should tilt very slightly upwards so that its surface is at right angles to your eyes. This way you eyes do not need to refocus as you move from top to bottom of the screen.

But … this might cause the screen to reflect overhead lights if the tilt is excessive.

The perceived brightness from your monitor should be similar to the area directly behind it. The ideal is to match the contrast of the screen to the surrounding area. If there is a dramatic contrast your eyes need to work harder and adjust more, leading to fatigue.

But … if you are in an office lit by daylight, you may need to adjust the brightness through the day.

If left uncorrected, glare will cause discomfort, eyestrain and headaches. Try to reposition your monitor so that there is no glare on the screen.

1. Screen-mounted document holders attach to the side of the monitor and hold the document in the same plane. This is good for single sheets of paper or lightweight documents.
2. Freestanding document holders can support a book but take up desk space.
3. Professional typesetters have the document just behind the keyboard and therefore in line with the monitor. This eliminates sideways head movements and might be the only place to rest heavy reference books. Just wedge the book behind the keyboard and prop it against the monitor and peg the pages back with some paper clips and you are set up.
4. Avoid placing documents flat on your desk while working with them if you have to copy from them. You'll probably have to twist and tilt your neck and adjust the focus to read them. However, for occasional reference, such an arrangement is fine.

Take time to set yourself up if you are going to use the computer for an extended period, especially if it involves typing. Raise your seat so that your elbows are slightly higher than the keyboard.

Don’t settle for the hotel desk, chair or surface if it is too high. Use pillows to raise the seat. Libraries have been designed for note-takers rather than typists, so limit yourself to short bursts of typing. Your lap is always an option but you might need a tray or a briefcase to rest the laptop on so that it can rest on your knees and put the keyboard in reach. But be careful not to bend your neck too far down.

When looking down at the screen, be careful not to bend your neck and head too far forward. One trick is to tuck your chin in to look down as this keeps your head and neck balanced over the spine.