Q. Why do people commonly refer to light therapy as "Bright Light Therapy"?
A. Light therapy began in 1982 when it was discovered that extending the length of day with high intensity, "bright" visible light would alleviate major depression in an individual who became depressed every winter. This followed on the discovery 2 years earlier that human physiology, like that of other mammals, is sensitive to the effect that visible light has on an internal biological clock in the brain.
In other mammals it was known that a light sensitive body clock in the brain receives information from the eye to regulate circadian (daily) physiological rhythms as well as seasonal changes.The reason it was not recognized that light affects humans is that other mammals respond rapidly to lower intensities of sunlight or white light, while humans uniquely need exposure to high intensities of sunlight or white light to regulate their internal body clock. Since early studies of light therapy showed that humans need ocular exposure to high intensities of white light to stimulate this region of the brain, "Bright Light" therapy lamps were used to regulate these rhythms.
Researchers at Sunnex Biotechnologies deduced that it is the unique physiology of the human eye that necessitates the need for high intensity white light to influence the intenal biological clock, and therefore for light therapy. Through an understanding of retinal physiology and the mechanisms by which absorption of visible light can influence living cells, they determined that human sensitivity to light therapy would be dependent on wavelength / color), as well as intensity.
After conducting trials with light of a variety of different wavelengths, the Lo-LIGHT lamp was developed to provide wavelengths of light from the shorter region of the green visible spectrum which they determined were most effective for light therapy. Subsequent independent clinical studies have verified Lo-LIGHT lamps providing the intensity of light normally found indoors, (a brightness of around 250 to 300 lux), are capable of inducing the equivalent response to a "bright light" therapy lamp providing 10,000 lux of white light. Patents were then obtained for the use wavelengths from this portion fo the visible spectrum for light therapy.
There has been widespread misinformation regarding the effectiveness of visible light
wavelengths in blue region of the spectrum, (i.e. wavelengths shorter than 480 nm), for light therapy.
It has been claimed blue light contains the most effective wavelengths for light therapy. This is not true.
There is now abundant evidence in the literature confirming the original findings of our trials of the
wavelength sensitivity of humans which found that blue light is not particularly effective for light therapy.
A major study from Harvard University has confirmed that blue light (460 nm) is not more effective for light therapy than white light. This study was authored by many of the researchers whose earlier work is generally cited to support the use of blue light wavelengths in light therapy. This is discussed in more detail here and here.
Retinal experts have also cautioned about repeated exposure to the higher levels of
blue light wavelengths provided by bright light therapy and blue light therapy lamps. Repeated exposure
can damage the retina and contribute to an advance in the onset of age related blindness.
See the effects of bright and blue light on the eye.
Lo-LIGHT phototherapy lamps emit no blue light wavelengths and provides only those visible light wavelengths which are most effective for light therapy. The elimination of blue light wavelengths together with the lower intensity of light from Lo-LIGHT lamps makes the use of these Lo-LIGHT lamps safer than being exposed to normal indoor lighting. For example, because antidepressant medications and lithium sensitize the retina to damage from blue light, researchers selected Lo-LIGHT lamps for studies on combining light therapy with photosensitizing medications. Ref 1, Ref 2
Independent studies by the USAF and Canadian Defence Department's R&D Centre comparing
low intensity Lo-LIGHT lamps with high intensity, "blue enhanced"
light therapy lamps found that Lo-LIGHT lamps had a stronger
effect on the biological clock than the high intensity therapy lamps.
In North America, a no-risk rental program is available on some models. If the unit is purchased within 2 months from the time of rental, all rental payments are applied towards the purchase price. Order Now!
The Sunnex Biotechnologies Lo-LIGHT phototherapy lamp comes with a two year warranty. Details