Light Therapy - White Light VS Blue Light

Tracy R. Nasca

Light therapy for the treatment of a variety of sleep disorders is growing rapidly and meeting with impressive results. The Talk About Sleep offices have received inquiries about the safety of white light versus blue light. There are rumors floating around that white light is safer. To dispel disinformation, I called Dan Adams, Research Director with Apollo Health to ask him to explain the controversy to me. We sell Apollo Health products and I personally use goLITE which is blue light therapy for delayed sleep phase syndrome. I wanted to know more about this to be able to better inform our membership and callers.

Tracy Nasca: Thank you for taking time for this interview to get some questions answered and to educate us on this relevant and important topic. Dan, tell me about the difference between blue light and white light technology in treating sleep disorders.

Dan Adams: The fact is that blue light is far superior to white in shifting circadian rhythms, suppressing melatonin and mediating the circadian response. This is because the photoreceptors that are responsible, are NOT rod and cone cells as we previously supposed, but are the ganglion cells that contain the photopigment MELANOPSIN. There is a MOUNTAIN of evidence now that melanopsin is responsible, and the fact is, that melanopsin is sensitive to 470-480 nm, and NOT 550 nm, which is the peak of the spectrum that white light represents.

Tracy Nasca: Dan, some callers have asked if blue light is dangerous to our eyes? One person heard it would make them go blind!

Dan Adams: Now, the first question I would ask is: If blue light (470 nm) is so dangerous, if it makes people go blind, then why in the world did our eyes evolve to respond solely to 470 nm light? If that is the exact wavelength our bodies need, how can it possibly be dangerous? Because if it were, we would have evolved a different response mechanism over all these eons of time. It is ludicrous to think otherwise.

Second question: If blue light is dangerous, then shouldn't 10,000 lux lightboxes be even more dangerous, since they contain far greater amounts of light, including blue light? The answer is of course, that 10,000 lux lightboxes are safe, and BLUEWAVE technology is even safer. P. Gallen, et. al. did a 6 year study on 10K light boxes and showed that there was no ophthalmological risk in using light therapy. Brainard et al, in the Biol Psych study, submitted the irradiance data to the FDA, who concurred that the intensity and type of blue light was perfectly safe to use.

Here, let me read you the quote:

"Although the study anticipated a viewing distance of 50 cm, light safety was assessed at shorter distances as well, including at the panel surface (0 cm). The Food and Drug Administration's Center for Devices and Radiological Health reviewed the full report and concurred with the analysis and findings based on the radiological measures provided" -G. Glickman et al. Biol Psychiatry 2006;59:50-507

In other words, BLUEWAVE technology was tested for ocular safety even at eye surface distance (0 cm), and found to be safe.

Dan Adams: Here's another important point: all those who bash blue light, have to ignore completely the mountain of evidence showing that it is the blue wavelengths that we respond to. No one can get around that. Study after study shows that rods and cones alone don't do it. At best, they perform a secondary function. You have to excite the melanopsin photoreceptors, and to do that, you need blue light.

Tracy Nasca: Dan, it sounds to me like other companies are bad mouthing BLUEWAVE technology as a marketing ploy.

Dan Adams: False comparisons: In order to say that our product is bad, these people cite data that shows that the blue light in sunlight is potentially harmful. Their false assumption is that since blue sunlight may cause damage, any blue light must be dangerous. You can see the fallacy in that. Is your computer screen dangerous because it is blue? Is your TV dangerous because it is blue? Of course not! You have to factor in intensity, and any light at a high enough intensity is dangerous.

The real issue: There is some evidence that blue light found in sunlight may cause macular degeneration over a span of about 60 years. You have to remember that we are only talking about a specific population here, that is predisposed, genetically to macular degeneration, and it takes about 60 - 80 years to develop with consistent exposure to sunlight. FACT: the goLITE produces 1/20 th of the amount of blue found in sunlight! So even if you were predisposed to AMD, it would take you 1200 years for the goLITE to cause damage.

The fact is, that those who have the most to lose from this new technology are the 10,000 lux white light people. So they do what they can to promote false information about our products and draw inaccurate comparisons. They misquote and misuse research papers to bolster their point. But again, they can't say anything about any of the new research from the last 5 years because it shoots them down.

Tracy Nasca: Dan, how would you summarize our discussion today?

Dan Adams: Look, there is a lot of misinformation out there. It is true that if you look at the sun, you will go blind, and that includes white light and blue. The issue here is intensity. The blue in the goLITE is far less than the blue in traditional light boxes. The blue in sunlight can contribute to AMD, but it takes 60-80 years, and the levels of blue in the goLITE are 1/20 th that of sunlight. There are NO studies which suggest that the level of blue in the goLITE contribute to AMD, to the contrary, evidence shows that the goLITE's wavelength is very safe. The goLITE has been demonstrated safe from an ocular hazard safety analysis, whereas other lightboxes do not (if they aren't from us). Finally, another very reputable site, the Mayo Clinic, demonstrates the goLITE on their site for Seasonal Affective Disorder.

As you may know, in 2001, researchers at Surrey and Thomas Jefferson independently discovered that our body clocks are highly sensitive to short wavelength light (460 - 480 nm), and not to white light (represented by 550 nm), as we had previously supposed. In fact, George Brainard's group at Thomas Jefferson showed that 464 nm light was five times more effective at suppressing melatonin than 550 nm, and I think Kavita Thapan's group had similar results.^1,2

Since then, several studies have shown that very low levels of blue light (approximately 470 nm), are at least twice as effective at shifting circadian rhythms, suppressing melatonin, and producing an alert response.^3,4 Vicki Warman at Surrey also demonstrated that extremely low levels of blue (8 lux) suppressed melatonin as efficiently as 12,000 lux of white light.⁵ The melatonin and circadian rhythm markers are particularly important, because we use those in determining a response to light when dealing with circadian disorders such as SAD.⁶

As a result of this discovery, several papers were then published in Science, Nature, Neuroscience and Endocrinology, etc, revealing that the photopigment melanopsin is primarily responsible for the circadian response, not rod and cone cells, and melanopsin's action spectrum is 460-480 nm.^7,8,9,10 It is now a well established fact that very low levels of blue light are superior to high intense white light at shifting circadian rhythms and suppressing melatonin. Indeed, blue LED light alone has been shown to be twice as effective as 10,000 lux white light and white LEDs, even though these other light sources produced far more blue.¹¹

Because SAD is classified as a circadian rhythm disorder, and shifting circadian rhythms is an important part of treating SAD, one would suspect that low level blue light would be as at least as effective as 10,000 lux in treating SAD. However, SAD manifests an additional depressive component, which must be taken into account. Thus, studies with blue light and SAD have been conducted to determine whether BLUEWAVE technology is an effective treatment for SAD."

To date, three studies using BLUEWAVE light have been conducted, and two more are currently under way. The first, "Light therapy for Seasonal Affective Disorder with Blue Narrow-Band Light-Emitting Diodes (LEDs) ", demonstrated that 30 subjects responded at least as well to 470 nm light as white light. This study also noted that a larger sample size needed to be done in order to verify those results. This study is published in the journal of Biological Psychiatry (May 2006).¹²

A second study at Brigham and Women Hospital (Harvard), "Comparing Wavelengths Using LED Light for SAD Treatment" , showed a response to 470 nm light in half the time compared to white light. Although this study also concluded that while blue was as effective, a larger population would be needed to confirm the faster response. This study is currently in press with the Journal of Biological Psychiatry, and the abstract is enclosed.

A third study at the University of Utah Medical School entitled, " LED Blue Light is Superior to Red in the Treatment of Seasonal Affective Disorder in Adults ", compared BLUEWAVE light to a red placebo light that was as visually as bright as the blue device. A criticism of previous light studies was that the dim red light is an obvious placebo. In this study, participants expected the red to be the active wavelength because of its intensity. However they concluded that 60% of patients responded to blue light while only 13% responded to the placebo, and the response was similar to other 10,000 lux studies (Abstract enclosed).

In all, nearly 100 subjects have participated in SAD studies using BLUEWAVE technology, which is highly significant in our industry. Also significant is the fact that these studies achieved excellent results using the small goLITE. I believe that because the bandwidth of light is superior, we were able to achieve similar results with a portable device. As you know, light therapy is not the most convenient intervention, and anything which promises greater portability and convenience should increase customer acceptance and compliance. In addition, most researchers believe that the low-intensity blue light should also reduce side effects associated with 10,000 lux light therapy.

Ocular safety is a particular concern with light therapy, since patients could conceivably use a light device for decades. The consensus among researchers is that 10,000 lux light is safe, but some people have raised questions about blue light safety. BLUEWAVE Technology produces far less blue light than 10,000 lux light boxes, and 1/20 th the amount of sunlight. We've also submitted our lights for Ocular Radiation Hazard testing by Dr. David Sliney, one of the foremost ocular physicists world-wide. BLUEWAVE passed at 15% of the threshold for ocular safety.

Additionally, in the first publication of using BLUEWAVE for SAD in Biol Psych, it states:

In other words, BLUEWAVE technology was tested for ocular safety even at eye surface distance (0 cm), and found to be safe.

This graph compares the photon density of sunlight, various standard 10,000 lux light products and BLUEWAVE. As you can see, BLUEWAVE produces substantially less blue than 10,000 lux or sunlight. Additionally, the blue shaded area represents the 'action spectrum' where light is most effective. Some light boxes produce very little light in this area.

I suppose I could argue why we believe 10,000 lux is not as effective, but we don't want to discount all of the valuable research with white light. We continue to support white light and have engineered our BRITEWAVE technology to produce the effective level of blue to make the white more effective. I think the conclusion at this point is that both therapies are safe and effective for treating SAD and related circadian disturbances.

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Dan Adams is Research Director at Apollo Health, Inc.

He graduated from Brigham Young University in 1987 and worked for 11 years in the health care industry before becoming research director for Apollo Health. He has spent the last 10 years developing and coordinating research studies with major universities including Cornell, Harvard, Rush Presbyterian (University of Chicago). In addition to working with the leading sleep and chronobiology researchers, Mr. Adams often presents at major medical society meetings such as the Associated Professional Sleep Society. He has also developed Apollo's web-based circadian rhythm assessment tool and provides content on circadian rhythm disorders to hundreds of thousands of readers.

Apollo Health specializes in the daily cycles, or circadian rhythms that affect the body's sleep, mood and energy. Circadian rhythm disorders can result in insomnia, Seasonal Affective Disorder, shift work sleep disorder, and depressive disorders. Apollo is the recognized leader in circadian rhythms and light therapy, and has participated in over 100 published studies in peer-reviewed journals.

Footnotes

G. Brainard, Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor Journal of Neuroscience, August 15, 2001, 21 (16):6405-6412
K Thapan, et al. An action spectrum for melatonin suppression: evidence for a novel non-rod, non-cone photoreceptor system in humans. Journal of Physiology (2001), 535.1 , pp .261-267
3. S. Lockley et al. High Sensitivity Of The Human Circadian Melatonin Rhythm To Resetting By Short Wavelength Light. The Journal of Clinical Endocrinology & Metabolism 2003; 88(9):4502-4505
4. S. Lockley, et al. Short-Wavelength Sensitivity for the Direct Effects of Light on Alertness, Vigilance, and the Waking Electroencephalogram in Humans. Sleep, Vol. 29, No. 2, 2006, 161-168
V. Warman, et al. Short-Wavelength Sensitivity of the Human Circadian System to Phase-Advancing Light. Journal of Biological Rhythms, Vol. 20 No. 3, June 2005 270-272
A. Lewy, et al. The circadian basis for winter depression. Proceedings of the National Academy of Science May 9, 2006 vol. 103 no. 19 7414-7419
Panda S et al. Illumination of the Melanopsin Signaling Pathway. SCIENCE 2005; 28 January (307) 600-4
Dacey DM et al. Melanopsin-expressing ganglion cells in primate retina signal colour and irradiance and project to the LGN. NATURE 2005; 433: 749-754
Qiu X et al. Induction of photosensitivity by heterologous expression of melanopsin. NATURE 2005; 433: 745-749
Melyan Z et al. Addition of human melanopsin renders mammalian cells photoresponsive. NATURE 2005; 433: 742-745
H. Wright et al. Light emitting diodes can be used to phase delay the melatonin rhythm J . Pineal Res . 2001; 31:350-355
Glickman G. et al. Light Therapy for Seasonal Affective Disorder with Blue Narrow-Band Light-Emitting Diodes (LEDs). Biol Psychiatry 2006;59:50-507