The Dangers of Computer and Screens: The Dangers of Blue Light

I have written and spoken at length about the dangers of computers on the Meibomian Glands and the role of screen time on contributing to chronic, debilitating dry eye. When one looks up “Dangers of Computers” online, most hits are about the risk of identity theft.

Many MDs and researchers are finally realizing that screen time is putting everyone at risk for more than identity theft: screens are putting everyone at risk of eye health theft, happiness theft.

Here is my posting on the risk of Meibomian Gland loss from excessive screen time, which is a tragic issue in kids.

Researchers are now worried about the risk of screen time and the blue LED lights, that is lighting up the screen you are reading this, with a series of potential health hazards:
1. Macular Degeneration, which is a disease that can lead to potential blindness
2. Circadian clock disruption which can lead to (proven in other studies with Circadian clock disruption: obesity, diabetes, breast cancer, gastrointestinal alterations, sleep and cognitive impairments, and breast cancer, psychiatric disorders, such as depression, anxiety, mania, suicidal ideation. (Ref 2, 3, 5)  

An aside: If you have a child suffering from ADHD, depression or other psychological issues, I would recommend to get rid of the TV & screens at home and school if used only for entertainment or limit them if they are only using them for learning and not wasting their time. This is counter-cultural as most schools now have computers, but it is not worth the potential risk. We do not have studies yet to say screens cause ADHD and depression as there are many factors, but screens do affect human’s circadian rhythms and these screens affects kids circadian rhythms more adults. 

The Circadian Clock is really a concept to describe almost all human cell’s ability to regulate the body’s systems properly automatically. 

The Circadian Clock is located in the brain’s hypothalamus and is called the suprachiasmatic nucleus (SCN). It is the master circadian clock controlling behavioral and physiological rhythms. It helps you sleep well and night and wake up in a good mode. It is affected by environmental light exposure, particularly blue light. There are circadian clocks in other body parts, such as the liver, which can be affected by food intake (Ref 4). Those patients who tell me they do not sleep well at night, often have a tv or screen in the bedroom. 

We now all live in a “Screen Dominated” world. It was obviously not always like this, though the light from the fire in caves and campfires do emit blue light, our eyes are being bombarded by blue light for many hours each day. Many studies are showing that this blue light and non-natural spectrum light and excessive exposure to blue light is affecting our body’s ability to function properly. 

More and more, researchers and MDs are calling on all policy makers, politicians, principals, manufacturers, and parents, to decrease our children’s exposure to blue light especially at night but I would also argue during day and especially at school.

International groups are finally noting the potential phototoxic risk of blue light on the retina and a potential negative impact on sleep and non-visual/circadian biology. While it will take years and millions of dollars to fund a randomized, double-blinded, controlled study of thousands of patients or students, the French Health Agency (ANSES) and the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) acknowledged the seriousness of the risk of blue light.

In 2013, the American Medical Association (AMA) reported the risks of blue light in, “Light Pollution: Adverse Health Effects of Nighttime Lighting.” (Ref 5). The AMA states,“exposure to excessive light at night, including extended use of various electronic media, can disrupt sleep or exacerbate sleep disorders, especially in children and adolescents,” and “disruption of circadian rhythmicity and sleep from the indiscriminate use of electric light at night may well increase risk of many of the diseases of modern life, including not only certain cancers but also obesity, diabetes, and psychiatric disorders.” (Ref 5)

Clearly, more studies on the potential long-term effects of extensive exposure to blue-rich LED lighting on the human body are needed especially on kids. Why they did not do such studies BEFORE computers were allowed into most schools is unclear to me. Now that we know of the risks of screens, I would argue that it is in the nation’s best interest to get the screens back out of all schools until we can study this properly.

In the meantime there are things teachers, parents, and all citizens can do to protect their eyes and their loved one’s eyes.
1. Limit screen time to necessary work. Avoid social media, video games, tv as much as possible. 
2. Avoid screen time for the 3-4hrs before bedtime
3. No screens in bedrooms: I would recommend to avoid any screens in kids bedrooms at all costs! Do not let them have a phone in their room. Do not allow friends to bring their phones for sleep overs. These screens are addictive and many patients tell me they “NEED” the tv to put them to sleep. They do not realize the health damage they are doing. It is ironic for people to “go organic” and “green” but still have screens in their bedroom. It defeats the purpose of “eating healthy.” 
4. Avoid screens in school rooms for social media purposes. Supervised screen time for students for education should be limited to a computer lab so students can be evaluated on their blink rate, looking away rate, and having frequent breaks to look away from the computer
5. Formal training to all students, parents, people on the importance of blinking, looking away, being in natural light, eating a healthy Omega 3 rich diet, warm compresses/lid hygiene daily, gentle lid massaging if not a high myope. 
6. Work in buildings where natural daylight during daytime hours is plentiful.
7. Work lights that have reduced glare, increased energy efficiency, control mechanisms patients can control.
8. Use adjustable controls for daylight harvesting and electrical lighting that interact with electrochromic “switchable” glazing for windows and skylights. 
9. Use light layering and dimmable lighting may that can be controlled and personalized over ambient light to enhance alertness during the active period and protect sleep during rest time.


1.  2017 Jun 16;3:9. doi: 10.1038/s41514-017-0010-2. eCollection 2017.

Global rise of potential health hazards caused by blue light-induced circadian disruption in modern aging societies.

Author information

Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo Japan.
PRESTO, JST, Tokyo, Japan.
Univ Lyon, Universiteé Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France.
Departments of Ophthalmology, Pathology, and Biological Structure, University of Washington School of Medicine, Seattle, USA.
Moran Eye Center, University of Utah, Salt Lake City, USA.
Catalonia Institute for Energy Research (IREC), Barcelona, Spain.
Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, USA.
Academy of Neuroscience for Architecture, Salk Institute for Biological Studies, La Jolla, USA.
Consulting Medical Physicist, Fallston, USA.
Department of Electrical and Computer Engineering, University of California, Davis, USA.
Institute of Transformative Bio-Molecules, Nagoya University and PRESTO, JST, Nagoya, Japan.
Member of the House of Councilors, Japan. Keio University School of Medicine and School of Law, Tokyo, Japan.


Mammals receive light information through the eyes, which perform two major functions: image forming vision to see objects and non-image forming adaptation of physiology and behavior to light. Cone and rod photoreceptors form images and send the information via retinal ganglion cells to the brain for image reconstruction. In contrast, nonimage-forming photoresponses vary widely from adjustment of pupil diameter to adaptation of the circadian clock. nonimage-forming responses are mediated by retinal ganglion cells expressing the photopigment melanopsin. Melanopsin-expressing cells constitute 1-2% of retinal ganglion cells in the adult mammalian retina, are intrinsically photosensitive, and integrate photic information from rods and cones to control nonimage-forming adaptation. Action spectra of ipRGCs and of melanopsin photopigment peak around 480 nm blue light. Understanding melanopsin function lets us recognize considerable physiological effects of blue light, which is increasingly important in our modern society that uses light-emitting diode. Misalignment of circadian rhythmicity is observed in numerous conditions, including aging, and is thought to be involved in the development of age-related disorders, such as depression, diabetes, hypertension, obesity, and cancer. The appropriate regulation of circadian rhythmicity by proper lighting is therefore essential. This perspective introduces the potential risks of excessive blue light for human health through circadian rhythm disruption and sleep deprivation. Knowing the positive and negative aspects, this study claims the importance of being exposed to light at optimal times and intensities during the day, based on the concept of the circadian clock, ultimately to improve quality of life to have a healthy and longer life.
2. Knutsson A. Health disorders of shift workers. Occup. Med. 2003;53:103–108. doi: 10.1093/occmed/kqg048. 
3. Kecklund G, Axelsson J. Health consequences of shift work and insufficient sleep. BMJ. 2016;355:i5210. doi: 10.1136/bmj.i5210.

4. Albrecht U. Timing to perfection: the biology of central and peripheral circadian clocks. Neuron. 2012;74:246–260. doi: 10.1016/j.neuron.2012.04.006.

5. Stevens RG, et al. Adverse health effects of nighttime lighting: comments on American Medical Association policy statement. Am. J. Prev. Med. 2013;45:343–346. doi: 10.1016/j.amepre.2013.04.011.

6.Hatori M, et al. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell. Metab. 2012;15:848–860. doi: 10.1016/j.cmet.2012.04.019.

7. Chaix A, Zarrinpar A, Miu P, Panda S. Time-restricted feeding is a preventative and therapeutic intervention against diverse nutritional challenges. Cell. Metab. 2014;20:991–1005. doi: 10.1016/j.cmet.2014.11.001

Diet, Fasting, and Your Circadian Clock:

Having periods of fasting in your day are very important to maintain a robust circadian rhythm. This in turn provides health benefits. Fasting not only affect the ability of the brain to regulate your Circadian Clock but also other organs, such as your liver and possibly kidney. 

There was a study where mice were given a high-fat diet only during normal waking hours. They restricted the time the mice were allowed to feed. These mice compared to control (non-restricted—able to eat at all times as desired) had a larger amplitude of expression of circadian clock genes and these mice were less likely to become obesity, have metabolic dysfunction, and liver damage. (Ref 6, 7).

Human studies have yet to be done and it will take years to do a good human study, but it makes sense that “When” you eat matters just as much as “What” you eat. 

Many religions have practiced fasting for years. We now have science to back up the health benefits that fasting can give.  

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