Lighting that is not appropriate for computer work is a major factor in visual discomforts such as eyestrain, burning or itchy eyes, headaches and blurred or double vision.
Lighting should be adequate for you to see the text and the screen, but not so bright as to cause glare or discomfort. For optimal comfort and performance, the following factors should be considered:
Amount of Light
- Bright light on the display screen "washes out" images making it difficult for operators to clearly see the work.
- Use light diffusers so that desk tasks (writing, reading papers) can be performed without direct brightness on the computer screen.
- Place rows of lights parallel to the operator's line of sight.
- Use operator adjustable task/desk lighting.
- If diffusers or alternative lights are not available, removing the middle bulbs of 4-bulb fluorescent light fixtures can also reduce the brightness of the light.
- Bright light in the operator's field of view (Fig. 1)
Bright light entering from a window.
- Use blinds or drapes on windows to eliminate bright light. Blinds should be adjusted during the day to allow light into the room, but not directly into the operator's field of view (Fig. 2).
- Lamps should have glare shields or shades and the line of sight from the eye to the light should be at an angle greater than 30 degrees.
- Reorient the work-station so that bright lights from open windows are not in the field of view. (Fig. 2).
- Use indirect or shielded lighting where possible and avoid intense or uneven lighting in the field of vision (Fig. 2).
Blinds on the windows and the
monitor placed at different angle.
Contrast of Light with Environment
- High contrast between light and dark areas of the computer screen, horizontal work surface, and surrounding areas.
- For computer work, well-distributed diffuse light is best. The advantages of diffuse lighting are two-fold: There tend to be fewer hot spots, or glare surfaces, in the visual field, and the contrasts created by the shape of objects tend to be softer.
- Use light, matte colors and finishes on walls and ceilings in order to better reflect indirect lighting and reduce dark shadows and contrast.
For more about office ergonomics, please see the following articles:
- Test Your Ergonomic Savvy...How Safe Is Your Work-Station?
- Ergonomics: How to Set Up Your Keyboard and Mouse
- Healthy Living Center
Portions of the above information has been provided by the Occupational Safety & Health Administration (http://www.osha.gov/)