Not using the proper positioning can cause muscle strain and nerve disorders. Keep your elbows close to your sides. Avoid bending your wrists. Raise your chair or use a cushion so that your wrists can be straight when you type. A Problem Illustration Glare is another common problem that occurs when VDT's are used.
Natural light coming from windows is one thing that creates glare.
To combat this, adjust your blinds or drapes to reduce incoming sunlight. In most cases this will prevent sunlight from striking the screen. Tiliting your monitor to change its angle toward the light can help as well. Artificial light can also cause glare problems. Frequently cleaning your monitor screen.