Light Box Treatment for SAD
Light box treatment for seasonal affective disorder (SAD) has traditionally consisted of exposure to a white light source. Because light is the most important environmental stimulus for regulating circadian cycles and because blue light is far superior to white in shifting circadian rhythms, many have suggested that blue light would be the treatment of choice for Seasonal Depression. Though some research has found success in treating SAD with exposure to a lower wavelength light from the blue areas of the visible spectrum, there are differing opinions regarding blue light vs white light.
Because blue light is known to be more capable of causing damage to the retina, many researchers and clinicians recommend exercising caution, or possibly avoiding blue light for the treatment of SAD to minimize the risk of macular degeneration. Advocates of the use of blue light for the treatment of SAD note that any light at a high enough intensity is dangerous and that any potential risk is related to how long you're exposed each time you use the light box. They argue that in assessing the risk of exposure to 10,000 lux white light versus blue light the need for a shorter duration of exposure with blue light may offset the absolute risk that is greater than exposure with while light.
For many individuals, convenience and cost may influence the decision about which technology to employ. In general, the white light boxes cost more and are physically larger, whereas the blue light boxes are less costly and are more portable. However, because the white light boxes are larger, they can be used at a more comfortable distance.
Regardless of the technology, the recommended intensity of the light for the treatment of SAD is 10,000 lux. Boxes which emit less than 10,000 lux must be used for a duration that is inversely proportional to their intensity; a 2500 lux box (1/4 intensity) must be used 4 times as long as a 10,000 lux box.
The Center for Environmental Therapeutics (CET) summarizes their recommendations for choosing a light box for treatment of SAD:
- Any light box you buy should have been tested successfully in peer-reviewed clinical trials.
- The box should provide 10,000 lux of illumination at a comfortable sitting distance.
- Fluorescent lamps should have a smooth diffusing screen that filters out ultraviolet (UV) rays. UV rays are harmful to the eyes and skin.
- The lamps should give off white light rather than colored light. "Full spectrum" lamps and blue (or bluish) lamps provide no known therapeutic advantage.
- The light should be projected downward toward the eyes at an angle to minimize aversive visual glare.
- Smaller is not better: When using a compact light box, even small head movements will take the eyes out of the therapeutic range of the light.
There are approximately a dozen manufacturers of light boxes for the treatment of SAD. Most have an internet presence and offer a 30 day trial and money back guarantee.