Older monitors, which work just like older televisions, took up so much desk space that workers were often left with no choice but to sit close to the monitor, says Windel. But that's not a problem with the newer liquid crystal display (LCD) monitors.
"Newer LCD monitors are becoming more common in offices," says Armin Windel of the German Federal Institute for Work Safety and Work Medicine (BAUA) in Dortmund. They are popular because they take up less desk space and offer more image stability and clarity.
Experts say they are not perfect. LCD monitors have problems with contrast and colour quality, making them less than perfect for graphics or computer aided design (CAD). However, they are fine for basic tasks like word processing.
When replacing a cathode ray monitor with an LCD monitor, make sure that the computer's graphic card will support the more modern monitor, otherwise you risk problems with image quality.
LCD monitors are usually delivered with a base that can be adjusted to a variety of heights and angles. Computer users should take advantage of this to make sure the monitor is set at the angle that best suits them.
When working at a computer, a user should sit with his head slightly bowed forward. The monitor should be able to turn without a problem and be able to be adjusted forward by five degrees and backward by 20 degrees.
The size of the monitor also affects work quality. "The bigger the screen, the bigger you can make images," says Windel. Seventeen inches is the standard size for LCD monitors. If a computer user is sitting 50 cm away, characters should be at least 2.9 mm tall. At 60 cm that should go up to 3.9 mm and at 70 cm distance, the character size should reach 4.5 mm.
Contrast is another important factor to watch. Dark characters on a light background are recommended because they mimic the images we are used to seeing on paper and are easier on the eyes. Many smaller companies are still using old computers that rely on a negative contrast -- light letters on a dark background -- but that's considered a poor alternative.