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" white 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. It had been recognized in other mammals a light sensitive body clock in the brain receives information from the eye that helps regulate circadian (daily) physiological rhythms, as well as seasonal changes. Sunlight, which is white because it is composed of all the wavelengths of visible light, is the light source that mammals generally utilize to regulate their internal body clock which is found in the brain of all mammals, including humans.
NOTE: The sun appears yellow because the shorter wavelengths of white light, the blue light wavelengths, are scattered by the atmosphere. The sky appears blue because we are seeing those blue wavelengths of sunlight that were scattered.
The reason it was not recognized that light also affected humans is because while other mammals respond to low intensities of sunlight or white light, humans uniquely need exposure to high intensities of white light to influence the light sensitive region of brain involved in regulating their internal body clock. This is a light-sensitive region of the brain not involved in vision, but which regulates mammalian physiology. Since early studies of light therapy demonstrated that humans need ocular exposure to high intensities of light to stimulate this region of the brain, the original light therapy lamps provided high intensity, very "bright" light, usually 5,000-10,000 lux.
In all mammals the retina of the eye detects the light signal which regulates the internal clock in the brain. Since only visible light wavelengths reach the retina of the adult human eye, it was realized that light therapy lamps should not emit UV or infrared light. This is the case with our Lo-LIGHT therapy lamp, and most other commercial light therapy lamps used for sleep and mood disorders. (More background at History of Light Therapy"
In the early 1990's, researchers at Sunnex Biotechnologies theorized that the reason humans needed to be exposed to high intensities of light to influence the light sensitive region of the brain not involved in vision was due to the unique physiology of the human eye. Through an understanding of retinal physiology they determined that human sensitivity to light therapy would be determined by wavelength, as well as by intensity.
After conducting trials with light of a variety of wavelengths, the Lo-LIGHT lamp was developed to provide those wavelengths of light to which it had been determined that light therapy would be most sensitive. It turned out these wavelengths were from the shorter region of the green visible spectrum. Subsequent independent clinical studies verified that low intensities of light emitted by Lo-LIGHT lamps were capable of inducing the equivalent physiological response, as measured by nocturnal melatonin suppression, as does white light that is about 20 times as bright.
There has been widespread misinformation that visible light wavelengths in blue region of the spectrum, that is visible light with wavelengths shorter than 480 nm, are among the most effective wavelengths for light therapy. This is not true. We had found this in our initial studies on the wavelength sensitivity on humans and now there is abundant evidence in the literature confirming this. A few these papers can be found here.
A major study from Harvard University 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.
Additionally, it has been shown that exposure to the eye from these blue light wavelengths causes excessive stress to the eye, as indicated by the term "blue light hazard". There is considerable evidence that the accumulation of stress caused to retinal tissues when blue wavelengths of light are absorbed in the retina of the eye contributes to the aging of the eye, leading to age-related blindness. More on this subject, can be found at the effects of bright and blue light on the eye.
Sunnex Biotechnologies' Lo-LIGHT phototherapy lamps screen out the hazardous blue light wavelengths and provides only those visible light wavelengths which are most effective for light therapy. At the intensity provided by a Lo-LIGHT lamp, which is about the same as that provided by a regular reading lamps, there is no undue increased levels of retinal stress, as occurs with a bright light therapy lamp, a blue light therapy lamp, or blue-enhanced light therapy lamps. Thus the low intensity Lo-LIGHT using GreenLIGHT technology is not only more comfortable, but is also safe.
Q. Is a Sunnex Biotechnologies' Lo-LIGHT as effective as bright light therapy boxes?
Independent studies at university and military with Lo-LIGHT lamps have shown that low intensity (about 300 - 400 lux) Sunnex Biotechnologies GreenLIGHT has the equivalent physiological effect as does bright light (6,000 - 10,000 lux). Studies at the Harvard Medical School confirm that the green light wavelengths provided by Lo-LIGHT lamps are the most effective wavelengths of light for regulating circadian rhythms. In addition to clinical trials with Lo-LIGHT lamps for winter depressives, peer reviewed controlled studies with Lo-LIGHT lamps using Sunnex Biotechnologies' GreenLIGHT technology demonstrated dramatically improved responses in patients with people with non-seasonal major depression, (both unipolar and bipolar) who are starting on an antidepressant medication. These studies explained their use of low intensity light therapy because most anti-depressant medications increase the risk of retinal damage from bright/blue light, while the Lo-LIGHT is not harmful to the eye. Reference 1 Reference 2
Follow up studies published in the Journal of Clinical Psychiatry and JAMA Psychiatry (formerly the Archives of Gen Psychiatry) found that low intensity (400 lux) of GreenLIGHT therapy in conjunction with sleep deprivation induced "rapid and sustained amelioration of depression"" in patients with bipolar disorder.
Additional evidence of the Effectiveness of Sunnex Biotechnologies GreenLIGHT technology.
In addition to studies on depression, independent studies with Lo-LIGHT Twin Tower lamps by the USAF and Canadian Defense Department's R&D Centre found that Sunnex Biotechnologies' Lo-LIGHT lamps are twice as effective as light therapy devices such as the Litebook® for which light from the blue portion of the spectrum (465 nm) is dominant, even though the Lo-LIGHT provides less than 1/10th of the light intensity (energy) of these devices. Ref The finding that low intensity green light from a Lo-LIGHT is effective for shifting human circadian rhythms is consistent with those found by the U.S.Coast Guard's R&D Center. After years of trials measuring the physiological response to exposure of Sunnex Biotechnologies GreenLIGHT technology in the laboratory as well as on operational military and commercial vessels, the U.S. Coast Guard used GreenLIGHT lamps to develop light management protocols to regulate circadian phase in their Crew Endurance Management System (CEMS) for commercial vessels operating on inland or coastal waterways.
Q. Does research on "bright light" therapy apply to the low-intensity Lo-LIGHT Lamp?
A. The authoritative Cochrane Reviews on the use of light therapy for non-seasonal depression extended the definition of "bright light therapy" to the range of 400-10,000 lux in order to include Sunnex Biotechnologies' Lo-LIGHT in their assessment of active bright light therapies. This Cochrane Review also rated the study using the Sunnex Biotechnologies Lo-LIGHT as one of only two studies out of the 20 meeting the inclusion criteria for this review that achieved a quality standard of "A", as compared to the quality standard rating of "B" that the other studies included in the review achieved.. Click for more information on The Cochrane Review on Light Therapy for Non-Seasonal Depression.
Green Light therapy vs Blue Light therapy: Efficacy and Hazard to Vision
As the awareness that the effectiveness of light therapy is dependent on wavelength as well as intensity has grown, there has been an attempt to promote light therapy made up of, or supplemented with increased levels of blue light. Because of the substantial risk to vision that these products pose to the user, we have prepared a technical discussion comparing the scientific basis of Sunnex Biotechnologies patented low intensity green light therapy with that of blue light therapy. For an analysis of GreenLIGHT therapy vs blue light therapy, Click Here.
The compelling evidence that has accumulated from numerous studies over the past few years regarding the role that exposure to blue visible light plays in the development of AMD (Age-related Macular Degeneration) has led leading experts to caution the public that the detrimental effects of oxidative stress in the retina caused by blue light exposure accumulates over a lifetime and contributes to the development of AMD and that people should therefore restrict exposure to blue light wavelengths as much as possible. More information on this can be found at The Risk to Vision from Bright and Blue Light Therapy- Click Here
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 five year warranty. Details