Bright Light & Research

studies on bright light

A controlled trial of the Litebook light-emitting diode (LED) light therapy device for treatment of Seasonal Affective Disorder (SAD)

Scientific Breakthrough ~ Blue Light Wavelengths Increase Serotonin
 
Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor

What makes the Litebook unique?

A controlled trial of the Litebook light-emitting diode (LED) light therapy device for treatment of Seasonal Affective Disorder (SAD)

~ BMC Psychiatry, August 7, 2007, 7:38 doi: 10.1186/1471-244X-7-38
Paul H Desan¹ Andrea J Weinstein¹ Erin E Michalak² Edwin M Tam² Ybe Meesters³
Martine J Ruiter³ Edward Horn⁴ John Telner⁴ Hani Iskandar⁵ Diane B Boivin⁵ and Raymond W Lam²

¹Department of Psychiatry, Yale University, New Haven, CT, USA
²Mood Disorders Centre, Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
³University Medical Center Groningen, Groningen, The Netherlands
⁴Royal Ottawa Mental HealthCentre, Ottawa, ON, Canada
⁵Centre for Study and Treatment of Circadian Rhythms, Douglas Hospital Research Centre, Montreal, QC, Canada

The efficacy of LED light therapy device in the treatment of SAD was tested in a randomized, double-blind, placebo-controlled, multi-center trial.

The results of this pilot study support the hypotheses that light therapy with the Litebook is an effective tretment for SAD.

The electronic version of the complete article is available in PDF format; first you will need to download the Free Acrobat Reader from Adobe if you don't already have it,

then click here "Read Controlled Trial of the Litebook" to open the file.

Scientific Breakthrough
Blue Light Wavelengths Increase Serotonin

Several very recent studies, most notably research from a team headed by Dr. George Brainard at Thomas Jefferson Medical College in Philadelphia, have identified the specific wavelengths of blue light, 446-477 nm that are crucial in suppressing melatonin production in humans. ^1,2,3,4 As Dr. Brainard notes, "This discovery will have an immediate impact on the therapeutic use of light for treating winter depression and circadian disorders." Melatonin, the neurotransmitter that helps us sleep deeply through the night, is produced from serotonin. Suppressing melatonin production raises the levels of serotonin in our brains. This is the key goal of therapeutic bright light treatment. This neurological pathway entrains our circadian rhythm to be awake during the day and sleep deeply at night.

Four cells in the human retina capture light and form the visual system. One type, rod cells, regulates night vision. The other three types, called cone cells, control color vision. It's known that exposure to light at night can disrupt the body's production of melatonin, which is produced by the pineal gland in the brain and plays a vital role in resetting the body's daily biological clock.

Dr. Brainard and his group showed that the combined three-cone system didn't control the biological effects of light, at least not for melatonin regulation. But subsequent work led to the surprising discovery that a novel receptor was responsible for the effect.

The study looked at the effects of nine different wavelengths of light, from indigo to orange, on 72 healthy volunteers. Subjects were brought into the laboratory at midnight, when melatonin is highest. The subjects' pupils were dilated and then they were blindfolded for two hours. Blood samples were drawn. Next, each person was exposed to a specific dose of photons of one light for 90 minutes, and then another blood sample was drawn. Wavelengths of blue light had the highest potency in causing changes in melatonin levels, he explains.

This new research indicates that there is an as yet unidentified photopigment; most sensitive at theses wavelengths of blue light that controls theses neurological reactions to light. As another researcher notes, this 'provides the first direct evidence of a non-rod, non-cone photoreceptive system in humans' - one that is activated by blue light between 420-480 nm. ²

1. Brainard G, Hanifin J, Gresson J, et al (2001) Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor. Neurosci (16): 6405-6412
   
2. Thapan K, Arendt J, Skene DJ (2001) An action spectrum for melatonin suppression: evidence for a novel non-rod, non-cone photoreceptor system in humans. J Physiol 535 (pt 1): 261-7
   
3. Wright HR, Lack LC (2001) Effect of light wavelength on suppression and phase delay of the melatonin rhythm. Chronobiol Int 5:801-8
   
4. Max, M (2001) Molecular Basis of Phototransduction and Circadian Rhythmicity, notes on current research, Dept. of Physiology and Biophysics of Mount Sinai School of Medicine.

Action Spectrum for Melatonin Regulation in Humans:
Evidence for a Novel Circadian Photoreceptor

~ The Journal of Neuroscience, August 15, 2001, 21(16): 6405-6412
George C. Brainard et al, Department of Neurology, Thomas Jefferson University,
Philadelphia, Pennsylvania 19107. According to researchers, inspiration for this work
came from the Edgar Cayce readings, series 281.

"In general, relatively high light illuminances ranging from 2 500 - 12 000 lux are used for treating winter depression, selected sleep disorders, and circadian disruption (Wetterberge, 1993; Lam, 1998). Although theses light levels are therapeutically effective, some patients complain that they produce side effects of visual glare, visual fatigue, photophobia, ocular discomfort, and headache. Determining the action spectrum for circadian regulation may lead to improvements in light therapy. Total illuminances for treating a given disorder can be reduced as the wavelength emissions of the therapeutic equipment are optimized."

"Modern industrialized societies use light extensively in homes, schools, work places, and public facilities to support visual performance, visual comfort and aesthetic appreciation within the environment. Given that light is also a powerful regulator of the human circadian system, future lighting strategies will need to provide illumination for human visual responses, as well as homeostatic responses. The action spectrum presented here suggests that there are separate photoreceptors for visual and circadian responses to light in humans. Hence, new approaches to architectural lighting may be needed to optimally stimulate both the visual and circadian systems."

"In conclusion, this study characterizes the wavelength sensitivity of the ocular photoreceptor system for regulating the human pineal gland by establishing an action spectrum for light-induced melatonin suppression. The results identify the 446-477 nm portion of the spectrum as the most potent wavelengths providing circadian input for regulating melatonin secretion. These data suggest that the primary photoreceptor system for melatonin suppression is distinct from the rod and cone photoreceptors for vision. Finally, this action spectrum suggests that there is a novel retinaldehyde photopigment that mediates human circadian photoreception. These finding open the door for optimizing the use of light in both therapeutic and architectural applications."

What makes 'The Litebook' Unique?
by The Litebook Company Ltd

Why does The Litebook use LED’s instead of the more prevalent fluorescent tubes?

It is not about “lux” and raw spectral energy.  It is about selecting the proper shorter wavelength and the effect of that light on the human circadian rhythm (our internal ‘body clock’).

Research has proven that bright light treatment is a preferred way to induce melatonin suppression. Melatonin is a naturally-occurring hormone in our body.  Researchers believe that melatonin suppression plays an important role in diminishing the Seasonal Affective Disorder (SAD) and Winter Blues, a condition that describes seasonal changes in mood, energy, sleep, appetite etc.

Why does The Litebook use LED’s instead of the more prevalent fluorescent tubes?
It is not about “lux” and raw spectral energy.  It is about selecting the proper shorter wavelength and the effect of that light on the human circadian rhythm (our internal ‘body clock’).
Research has proven that bright light treatment is a preferred way to induce melatonin suppression. Melatonin is a naturally-occurring hormone in our body.  Researchers believe that melatonin suppression plays an important role in diminishing the Seasonal Affective Disorder (SAD) and Winter Blues, a condition that describes seasonal changes in mood, energy, sleep, appetite etc.

THE SCIENCE

The human eye has a varying range of sensitivity to light, depending on the wavelength.

‘Lux’ is a unit of measurement for light that was developed to account for the eye’s sensitivity curve, known as the photopic response curve.  Simply put, this means that light of one color may appear brighter than light of another color, even if their actual intensity is the same. As shown in the chart, a yellow light will appear much brighter than a deep blue light, even though their actual output may be the same.

Photopic response curve

For most applications, the Lux measurement is a very good approximation of how we will perceive the intensity of a particular light source. But, for our particular application, i. e. melatonin suppression, Lux appears to an inappropriate unit of measurement.

The melatonin suppression response curve is shown below. (Brainard et al, 2001)

LED technology allowed the Litebook inventors to match the peak light emission with the melatonin suppression curve, at around 460 nanometers, for maximum efficiency.

Since many experts believe that treatment of seasonal changes are related to effects of light on the circadian rhythms system and that the seasonal changes may be mediated by the effect of light on melatonin suppression, it makes sense to try to exploit light in the desired wavelength. There has been several research papers published in the last 24 months that confirm the efficacy of the short wavelength light for treating various conditions.

Further, it becomes clear that it is much less effective, and may even be counterproductive to use a bright light that produces energy outside of the efficacy envelope.

The charts above and below illustrate the ‘raw’ output of two sources of bright light at the same distance from the eye. The Litebook uses carefully selected white LEDs, and are compared to a typical fluorescent tube type light therapy device.  LEDs deliver a sharply focused, very narrow beam of light.  By specifying the appropriate wavelength, one can control the nature of the treatment. On the other hand, fluorescent tubes were designed to illuminate rooms, flooding the space indiscriminately with what amounts to ‘generic’ quality light.

Clearly, the fluorescent light produces more light energy within the visible spectrum. While this is useful for illuminating workspaces, much of the light produced is ineffective for the suppression of melatonin.

The particular fluorescent bright light therapy device tested -- emits 10,000+ Lux at a distance of 50 cm. It has plenty of power, but mostly in the ‘wrong’ wavelength for therapeutic treatment. On the other hand, most of the light emitted by The Litebook falls closely within the useful wavelength.

This final chart illustrates that wasted energy produced by the fluorescent light source is almost 3 ½ times greater than that of the Litebook. No wonder fluorescent lights use so much power (avg. 85W vs. 6.0W for Litebook).

Much of the energy produced by the fluorescent light is wasted with regard to the suppression of melatonin. What the results of the spectral analysis show is that in fact, The Litebook produces a superior quality of light for the desired purpose, with an overall intensity that is less than half of the fluorescent tubes.

This combination shows the error in using only Lux as a measurement of the effectiveness of a bright light device for treatment of SAD, Winter Blues, jet lag, etc. Rather, it is not the overall intensity of a bright light device, but rather the bright light at the appropriate wavelength that produces desired results. We believe this explains why Litebook users consistently report positive results in less time than with previous fluorescent light devices.

For more information about light see Light Researach & FAQs

web directory

Main Menu
Home   Site Map   Intro   Contact Us   Profile   Favorites   Notices
  Order   Canadian Price List   Specials & Discounts "Canada"

Bright Light Therapy Products
Phone: Amos 819-727-3170, Montreal 514-497-8153 or toll-free 1-866-566-6682
Litebook Elite  Litebook - Usage
 
 Nova MegaFitness Inc. Downloadable Products
Free eReport  Free eBook  Exercise4Life  Exercise4Fitness  EFT

 Educational Information
 Light Therapy   Research & FAQs   Bright Light & Research   Health & Light    Insurance

This website is brought to you by Nova MegaFitness Inc.,
Light Therapy Division: Orientations NOVA,
a registered company: Canada BN # 813 975 497, Quebec NEQ # 1165765703
111, 2d Street East, Amos, Quebec, Canada J9T 3G9
Telephone 819-732-5343    Fax 819-732-7830