Risk Management, Portland, OR 05/16/2013
Most office lighting problems are due to one or more of the following:
Glare is caused by the following:
- Reflections caused by window light;
- Reflected light from a glossy wall surface;
- Poorly located task light;
- Reflected light from a standard down lighting system.
Solutions to these problems are not complex, but can potentially be expensive:
- Window light can easily be controlled with blinds and other window coverings. Monitors should always be located at right angles to the window.
- Glossy wall surfaces can be frequently eliminated by painting walls and ceilings with a flat paint, producing a matte finish.
- Various task lights can be added for non-computer tasks but it is important to arrange these lights so that they produce no glare on the screen, or are left off when using the computer.
- The ideal solution to problems caused by outdated down lighting systems is a complete conversion to an indirect lighting system. This type of system directs all light to the ceiling, whose light-colored, matte-finished surface is then evenly washed in light. The resulting reflection is both shadowless and glare-free, providing the ideal environment for the user.
- Glare guards, while effective in reducing or even eliminating the glare on screens, also reduce the intensity of light being emitted from the screen as well as distort the character images being viewed. Both of these latter factors can contribute to vision fatigue.
Here are a few simple recommendations to help improve conditions in an overlit office:
- Turn off some of the overhead lights;
- Put all overhead lights on dimmer switches, controllable by individual users, which will also result in decreased energy consumption;
- Convert to an indirect lighting system.
When a monitor is placed near a bright background source, such as an uncovered window, your eyes, though focused on the screen, continually try to readjust to the different light levels emitted by the screen and the brighter (or darker) background source. This causes visual and sometimes general fatigue in the user.
Visual fatigue from staring has less to do with office lighting and is more an outcome of poor work habits. Computer users should be aware that they don't blink nearly as often when watching TV or looking at a screen, in fact people have a tendency to stare in these situations. A couple of simple tips can help to counteract this tendency:
- When using a computer, consciously blink more often. This helps to lubricate the eyes.
- Every fifteen minutes, pause to look away from the computer monitor.
Excerpted from: An Ergonomic Primer on Office Lighting, By Jeff Tiedeman, CSP, ARM (Click on link to read entire article)