Friday, May 10, 2019

Blue Light Blues: Melatonin Suppression and Breast Cancer

There is growing evidence for adverse ocular effects of blue light emitted from LED screens from computers, cell phones and tablets which can cause direct retinal damage and also inhibit melatonin production in the pineal gland and alter circadian rhythms. Melatonin is a potent antioxidant which is produced in the pineal gland and is also found  in the retina where it modulates genes responsible for circadian rhythms via the ganglion cell layer (Blasiak 2016).   Researchers have found photosensitive retinal ganglion cells (ipRGCs) in the mammalian brain which are not related to image formation but direct circadian rhythms, pupil constriction and alertness through 465nm blue light Vandewalle(2018).
This cascade of biological effects contributes to a host of chronic disease states, including high blood pressure, depression and cancer.
Dr David Blask and colleagues have conducted studies showing that light suppresses melatonin leading to stimulation of breast cancer growth. When they grafted human MCF-7 breast cancer cell xenograft on mice and exposed one to light- light and the other to light-dark environments they found the light- light group had increased cancer cell growth rates. (Blask 2002)   The International Agencyfor Cancer Research (IARC) classified shift work that involves circadian disruption as a “probable carcinogen”. (IARC 2007)

Harvard Recommendations for Reducing Blue Light Exposure

LED lights from lightbulbs, computers, cell phones, video games and tablets emit blue light from the screen.  Overhead LED lights that are now commonly used also emit more blue light than fluorescent light bulbs, and incandescent light bulbs emit the least blue light. Although much more energy efficient, LED lighting which has largely replaced incandescent in homes, businesses and street lights, may be creating a health risk through complex biologic effects on our melatonin levels and circadian rhythms.  Here are the Harvard guidelines  Blue light has a dark side. Updated August 13, 2018.
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Protect yourself from blue light at night (Harvard 2018)

  • Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin.
  • Avoid looking at bright screens beginning two to three hours before bed.
  • If you work a night shift or use a lot of electronic devices at night, consider wearing blue-light blocking glasses or installing an app that filters the blue/green wavelength at night.
  • Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.

sunglasses-1271913_1920Blue Light Blocking Glasses for Improved Physical and Mental Health

Amber colored blue light absorbing glasses, computer and cell phone screen covers have been developed to block blue light from artificial LED lighting and screens, typically 2-3 hours before bedtime.  More research needs to be done, however, scientists have found that using these blue light blocking devices may promote higher melatonin levels near bedtime thus reducing insomnia.  Evidence is showing the positive effects on blue light blocking glasses not only on sleep quality and timing (Zebrine 2018; Eskai 2016; Burkhart 2009) but also potentially on symptoms of mania in those with manic depressive symptoms by acting as physiologic “dark therapy” not necessarily related to melatonin production (Shirahama 2018; Henriksen 2016). Quality varies with the amount and spectrum of blue light blocked by different glasses. If you are purchasing glasses it is important to get high quality tested glasses and know which frequencies are blocked either full blue light blockage (400-500nm), full blue green blockage (400-550nm ) or specific blue frequencies (i.e.480nm)  blocked on the spectrum (from 400-550nm). In general the more full blue light spectrum blocked the better it will enhance melatonin production. Consumer Reports-3 Blue Blockers Put to the Test 
Apple has introduced “Nightshift” software into their new phones (OS9.3 and above)  that reduces blue light at night. You can access by pressing Settings >Display&Brightness >NightShift and set it to the times you wish the display to reduce blue light. Some research from the Lighting Research Center  has shown that  this Apple setting may not help you sleep as much as anticipated as the brightness of the screen and excess mental stimulation may also be factors on melatonin levels.

Dr. Charles Czeisler Discusses Broad Health Impacts of Poor Sleep

Charles A. Czeisler, MD, PhD, Chief, Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital, explains the critical impacts of sleep on brain function and physical health. He states that sleep is the third pillar of good health along with nutrition and exercise. Lowering blue light at night is component of healthy sleep.   Dr. Czeisler , whose group  has worked with astronauts to reset their circadian rhythms before going into space research, highlights the many bodily systems effected by insomnia including

Doctors Warn That LED City Street Lights Blue Spectrum Can Damage Vision
In  2016 the American Medical Association warned cities that the new energy efficient street light that were being installed to combat global climate change can harm the retina, affect circadian rhythms and sleep patterns. Studies have shown that brighter residential nighttime lighting is associated with sleep disruption. AMA Board Member Maya A. Babu, M.D., M.B.A states, “Despite the energy efficiency benefits, some LED lights are harmful when used as street lighting, The new AMA guidance encourages proper attention to optimal design and engineering features when converting to LED lighting that minimize detrimental health and environmental effects.”
News on Harm From LED Street Lamps

Fatal Collision: Harm from Wireless Eyewear

people-3365369_1920A new 2018 paper,  Fatal Collision: Are Wireless Headsets a Risk in Treating Patients?,   highlights the potential bodily  harm from wearing wireless headsets, augmented reality systems and glass-type eyewear.  Co-authored by Cindy Sage, who is also co- author of the Bioinitiative Report, this review article reveals that these devices, are connected to the internet and have similar radiation (2.4 and 5GHz) to cell phones. An association has been identified between long term cell phone use and brain cancers on the same side of the head. There is also the concern for lack of concentration and distraction when using these devices, similar to cell phones. Damage to eye structures is an obvious concern.
These wireless devices are increasingly being used in medicine (google glass-type wearables)  and by educators but no thought has been given to the harm from long term use. Children are seen in ads wearing wireless headsets for entertainment. It is the next best marketing and sales opportunity in technology.  Sage and Hardell note, “using wireless glass-type devices can expose the user to a specific absorption rates (SAR) of 1.11–1.46 W/kg of radiofrequency radiation. That RF intensity is as high as or higher than RF emissions of some cell phones. Prolonged use of cell phones used ipsilaterally at the head has been associated with statistically significant increased risk of glioma and acoustic neuroma.”  Studies are inadequate to determine safety of these wireless devices long term. There are to date insufficient protective guidelines for adults or children who are increasing using these devices for entertainment, in classrooms and therapeutically in medicine. Precautionary recommendations for use are needed.

Eye Absorption of Radiation from Cell Phones and Virtual Reality

In a new paper Fernandez et al (2018) reveals that young eyes and brains absorb 2 to 5 fold more radiation than that of an adult. He cautions that we need to reexamine regulations and compliance with regards to these devices as testing uses a large adult male (SAM) . Dr. Fernandez also advises precautions proposed by the American Academy of Pediatrics, that young children should not use cell phones. This study indicated virtual reality type devices should also not be used by children. He urges wired connections to reduce children’s  needless exposure to non-ionizing radiation. More research is critically needed in this area as widespread commercial use has already begun.
Fernandez Screen Shot 2018-10-29 at 11.41.15 PM
Reprinted with permission.


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Blue Light


Computer Vision Syndrome

  • Prevalence of dry eye in video display terminal users: a cross-sectional Caucasian study in Italy. (2018). Rossi GCM et al. Int. Ophthalmol. https://www.ncbi.nlm.nih.gov/pubmed/29881936
  • Eyesight quality and Computer Vision Syndrome.(2017) Bogdanici CM et al. Rom J Ophthalmic. 2017 Apr-Jun;61(2):112-116. https://www.ncbi.nlm.nih.gov/pubmed/29450383
  • Visual Fatigue Induced by Viewing a Tablet Computer with a High-resolution Display. Kim DJ.  Korean J Ophthalmic. 2017 Oct;31(5):388-393. https://www.ncbi.nlm.nih.gov/pubmed/28914003
  • Computer vision syndrome prevalence, knowledge and associated factors among Saudi Arabia University Students: Is it a serious problem? (2017)  Al Rashid SH. Int J Health Sci (Qassim) 2017 Nov-Dec;11(5):17-19. https://www.ncbi.nlm.nih.gov/pubmed/29114189
  • Exploring the Predisposition of the Asian Eye to Development of Dry Eye. (2016)  Craig JP et al.  Ocul Surf. 2016 Jul;14(3):385-92.  https://www.ncbi.nlm.nih.gov/pubmed/27143647
  • Computer vision syndrome and associated factors among medical and engineering students in chennai. (2014). Logaraj M. Ann Med Health Sci Res. 2014 Mar;4(2):179-85.  https://www.ncbi.nlm.nih.gov/pubmed/24761234
  • [Meibomian gland disfunction in computer vision syndrome]. (2010)  Pimenidi MK. Vests Oftalmol. 2010 Nov-Dec;126(6):49-52.
  • Computer Vision Syndrome: A Review. (2005) Bleh C et al.  Survey of Ophthalmology. May June 2005. Volume 50, Issue 3, Pages 253–262. https://www.surveyophthalmol.com/article/s0039-6257(05)00009-3/abstract https://www.ncbi.nlm.nih.gov/pubmed/29450383
  • Mobile phone related-hazards and subjective hearing and vision symptoms in the Saudi population. (2005) Meo SA and Al-Dress AM.  Int J Occup Med Environ Health. 2005;18(1):537. https://www.ncbi.nlm.nih.gov/pubmed/16052891

Non-ionizing Radiofrequency Radiation Exposure


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