What are signs of poor lighting?

The most common complaints are: eyestrain, eye irritation, blurred vision, dry burning eyes, and headaches.

Poor lighting affects not only the ocular system but can also contribute to stiff necks and aches in shoulder area. These problems can occur when people adopt poor or awkward postures when trying to read something under poor lighting conditions.

The monitor itself is a source of light. It does not require additional illumination from other sources. In fact, the screen can cause glare if the brightness and contrast controls are not properly adjusted.

An additional challenge occurs because most office work involves using the monitor and paper documents at the same time. Paper documents require a higher light level than the monitor. A desk lamp (any type of soft task light) can be used to illuminate documents while avoiding excessive light near the monitor. Glare can also result from an improper match or excessive contrast in light levels between the monitor screen and the paper.

The monitor also acts as a mirror. Reflections of objects, shiny walls, and any light source (specifically windows and overhead lighting) all cause glare. Eye discomfort can result, but glare also forces the user into an awkward position as they try to avoid having the glare in their eyes. These positions lead to aches and pains in the upper body that can also aggravate eyestrain.

The quality of the images on the monitor is another important factor. Reading and interpreting blurred, fuzzy, tiny, or otherwise illegible characters for hours a day can strain the operators’ eyes.

What else in the computerized office contributes to eye discomfort?

• Maintaining a fixed and close visual distance for a long time;
• Glare from the unshaded or un-diffused lighting fixtures;
• Poor lighting, involving unchanged (and unchangeable) levels of illumination;
• Unsuitable workstations (dimensions and arrangement);
• Low ambient humidity;
• Uncorrected vision problems; and
• Lack of color variety in one’s surroundings.

Reducing discomfort

• Use filters to diffuse overhead lighting.
• Dim overhead lights.
• Keep in mind that the recommended level of light in offices — 300 - 500 lux — is not a must. It applies in the situation where there is no task lamp in use.
• Cover windows with adjustable blinds.
• Use matte finishes on walls, floors and furniture.
• Adjust the computer monitor’s brightness and contrast according to your preference.
• Use a light color for the screen background.
• Place the monitor parallel (not directly below) with overhead lights.
• Angle the monitor away from lights and windows.
• Make sure that the task lamp illuminates the document and not the monitor.
• Uncorrected vision may be an additional source of eye discomfort. It may have further consequences resulting in aches and pains because of awkward postures or positions adopted to “see better”.
• Check your vision every one or two years, as recommended by your eye specialist.
• Provide your eye examiner with information about your job.
• Consider using task-specific computer glasses.
• Every few minutes look away from the screen for a few seconds.
• Look around.
• Focus your vision on distant objects.
• Blink several times. Frequently “stretching” your eyes like this will prevent feelings of fatigue from accumulating.
  Reprinted with the permission of the Canadian Centre for Occupational Health and Safety (CCOHS), 250 Main Street East, Hamilton, Ontario L8N 1H6; Tel: (905) 572-4400; Toll-free: 1-800-263-8466; Fax: (905) 572-4500; e-mail: inquiries@ccohs.ca