Lighting and glare
Direct light sources such as windows or overhead lights can cause reflected light to show up on the computer monitor, which makes images more difficult to see, resulting in eye strain and fatigue. Light should be directed so that it does not shine into the operator's eyes when the operator is looking at the display screen. Further, lighting should be adequate for the operator to see the text and the screen, but not so bright as to cause glare or discomfort.
Bright light sources behind the display screen can create contrast problems, making it difficult to clearly see the work. By using blinds or drapes the user can eliminate bright light. Blinds and furniture placement should be adjusted to allow light into the room, but not directly into the field of view. Vertical blinds work best for East/West facing windows and horizontal blinds for North/South facing windows.
If necessary, the workstation can be reoriented so that bright lights from open windows are at right angles with the computer screen. Glare screens can also be used to reduce the amount of glare on a monitor.