Preferable
position of light sources relative to computer workstation
Computer operators commonly report eye fatigue, eye strain
and irritation after working long hours in front of the computer monitor. These visual
symptoms can result from improper lighting, glare from the monitor, poor position of the
monitor or documents that are difficult to read. These problems can be corrected by
adjusting the furniture layout and environmental setting of the work area.
Light requirements may vary depending on the task
performed. For example, less light is needed for the operator to view the computer monitor
only, and more light is needed when viewing a document that is difficult to read. Computer
work areas require less lighting than other office work areas because of the illuminated
computer monitor. Room lighting should be only as bright as necessary for all tasks done
in the room. There are four basic lighting factors that can be controlled to achieve
proper office lighting: quantity, contrast, and direct and reflected glare.
Quantity
The Public Employees Occupational Safety and Health (PEOSH)
Video Display Terminal (VDT) Guidelines state that lighting in the room should be between
200 to 700 lux measured on horizontal surfaces of any computer workstation. More than 500
lux may be needed to read poor quality documents; and if no hard copy is used, less than
500 lux is usually desirable. Bright light can wash out images on the monitor.
Contrast
Contrast is the difference in brightness at the computer
monitor and the surrounding area. To prevent eye fatigue and soreness, the difference in
illuminance between the monitor and the work area should be minimized. Ways to improve the
contrast include:
- Adjusting the brightness and contrast levels on the computer
to reduce the contrast between the computer and the surrounding area.
- The brightness and contrast buttons can be found in front of
the computer monitor panel.
- Moving the monitor away from the windows or other sources of
bright light. Do not place the monitor with the screen directed toward the windows.
- Adjusting the window coverings to control the amount of
light entering the room.
Lighting and
Glare, Continued>>> |
