Before the invention and distribution of artificial lighting, the sun determined when people went to bed and when they woke up. While artificial light has extended the hours you may be productive, it comes at a price as it affects health, interrupts sleep patterns and circadian rhythms and may shorten your lifespan.
Digital devices are pervasive sources of artificial light. They emit high levels of blue light, which have a damaging effect on the photoreceptor cells located in the retina. This photosensitive tissue converts light into electrical signals that travel along the optic nerve to your brain, where the information is processed into what you “see.”
The light passing through your eyes occurs in a range of visible and sometimes invisible rays. The sun produces red, orange, yellow, green and blue rays that, when combined, create white light or sunlight. The wavelength of the individual ray is dependent on the energy level.
For instance, longer wavelengths have less energy and shorter wavelengths have more energy. Rays in the red visible light spectrum have longer wavelengths and less energy. Blue light has shorter wavelengths and more energy and is generally defined as light in a range from 380 to 500 nanometers.
Uninterrupted Blue Light May Shorten Your Lifespan
Recent data released by Oregon State University in collaboration with The Ohio State University1 found prolonged exposure to blue light may affect your brain, even when it's not shining through your eyes. Increasing levels of blue light are related not only to digital devices but also to commonly used LED technology.
Researchers used Drosophila melanogaster, the common fruit fly, to test their hypothesis about lighting, as it shares cellular and developmental mechanisms with animals and humans. Their initial question was whether fruit flies exposed to white light would age faster than those kept in total darkness.2
They first kept adult flies in a daily cycle of 12 hours of white fluorescent lighting followed by 12 hours of darkness. The second group was kept in constant darkness. After analysis of lifespan and neurological function, the researchers found that those in constant darkness exhibited a significantly extended lifespan compared to those who were in the light for 12 hours each day.
The light used in the experiments contained a substantial amount of blue light, which led to the second stage of the experiment. During this stage, the first group of flies was kept in blue LED light for 12 hours, followed by 12 hours of darkness. The second group was kept in white LED light with the blue wavelength blocked for 12 hours, followed by 12 hours of darkness.
Those kept in the blue line had a dramatic reduction in their lifespan, which was shortened by approximately 10%. The researchers noted accelerated damage to the retinal cells as well as neurodegeneration and impaired locomotor performance in the test flies.
In an attempt to ameliorate the reduced lifespan, the researchers added orange light to activate rhodopsin 1 in the fly retina, which is needed by the fly to regenerate damage. They also tested the effect blue light had on genetic mutants with reduced rhodopsin levels. While the median reduction in lifespan was shorter in mutants, the flies continued to demonstrate damage from the blue light.
The researchers did expect some damage from flies that could see and that were exposed to the light but they also found that flies exposed to blue light who were born without eyes also had a shortened lifespan. The researchers noted the results suggested a cumulative response to the light as the damage was more apparent in the flies as they aged. The researchers wrote:3
“Our discovery that lifetime exposure to artificial light may cause extra-retinal damage and reduce longevity in a complex model organism provides a novel opportunity to understand the molecular mechanisms of the increasingly evident harmful side of light.”
Retinal Damage May Lead to Blindness
Despite the fact that negative effects of blue light have been documented for several years, it continues to be the technology industry’s favorite color for all types of digital screens, as they believe it's aesthetically pleasing.4
A separate study5 released by the University of Toledo in August 2018 demonstrated that blue light from digital devices and from the sun is capable of transforming specific cells in the retina of the eye, causing damage. The researchers used cell cultures to investigate the possibility that blue light would excite retinal, a photoreceptor chromophore or chemical integral to vision.
They were interested in whether the excited retinal would interact with cells and intercept signaling. They found data which suggested “retinal exerts light sensitivity to both photoreceptor and non-photoreceptor cells, and intercepts crucial signaling events, altering the cellular fate.”
The results of the study came under attack by the American Academy of Ophthalmology (AAO), which has insisted since at least 2017 that blue light causes no eye damage.6,7,8 Following the release of this study, the AAO quotes The Verge, which asked the study’s lead author a straightforward question about whether using electronic screens causes blindness, to which he replied, “Absolutely not.”9
However, despite the insistence of the AAO, the same expert, Ajith Karunarathne Ph.D., from the University of Toledo, explained the findings further, saying:10
“We are being exposed to blue light continuously, and the eye's cornea and lens cannot block or reflect it. It's no secret that blue light harms our vision by damaging the eye's retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.
You need a continuous supply of retinal molecules if you want to see. Photoreceptors are useless without retinal, which is produced in the eye. No activity is sparked with green, yellow or red light. The retinal-generated toxicity by blue light is universal. It can kill any cell type.
Every year more than two million new cases of age-related macular degeneration are reported in the United States. By learning more about the mechanisms of blindness in search of a method to intercept toxic reactions caused by the combination of retinal and blue light, we hope to find a way to protect the vision of children growing up in a high-tech world.”
Interrupted Sleep Patterns May Affect Cognitive Function
As a body of evidence continues to grow demonstrating the damage blue light has on eyesight and brain cells, consensus has been building regarding the widespread use of blue light and the mixed messages it sends to your brain. In one survey, the researchers found nearly everyone who responded was using some type of electronic digital device within one hour of going to bed at least a few nights each week.
It has been shown in various studies that this type of exposure will significantly suppress melatonin production, important in the initiation of sleep. This then increases the amount of time it takes to fall asleep and reduces the quality of sleep.
Although the researchers asked about using electronic equipment, those exposed to LED lights in the evening hours may have the same experience. The American Medical Association has noted white LED lights have a significant impact on circadian sleep rhythms, which in turn may lead to difficulty with sleep and subsequent health conditions.
Healthy sleep patterns are vital and you should cycle through each stage four to five times a night. If you get less than six hours of sleep in any given 24-hour period it leaves you cognitively impaired, which may negatively affect your ability to drive, learn and be productive at work. It can also increase your chances of being in an accident.
Unfortunately, nearly 40% of those surveyed reported unintentionally falling asleep during the day at least once a month while 5% reported nodding off while driving. Chronic sleep deprivation costs the U.S. $411 billion each year in accidents and lost productivity.
Sleeping less than six hours a day, over the long term, will dramatically increase your risk of insulin resistance, which is the core of many chronic diseases including Type 2 diabetes and obesity. Sleep quality affects blood pressure, heart disease, heart aging and mental health.
Steps to Protect Your Eyesight, Longevity and Overall Health
It is important to remember you need blue light first thing in the morning to shut off your melatonin production. As it is an important part of your circadian rhythm, you should also seek to reduce your exposure to blue light after 7 p.m. when the sun naturally begins to set.
There are several ways you may do this in the evening depending upon your lifestyle and personal preferences. Many of your digital devices may have software installed or access to software to reduce the blue light on the screen. If you use this on your electronic devices and replace all LED lights with incandescent bulbs, you won’t need to consider blue blocking sunglasses.
However, if you don’t have control over your lighting or are unable to put software on the devices you use, strongly consider simple blue-blocking glasses to help regulate your internal clock and reduce damage to your eyes from high energy blue wavelength light. The simplest way is to begin wearing them at 7 p.m. or, if you consistently use a computer or electronic device, begin wearing them after noon.
During sleep you may also be exposed to light, such as from an alarm clock, street lamp outside your window, or light filtering in from another room. It is important that you rest in total darkness in order to experience quality sleep. Consider removing all light emitting devices and using a sleep mask and room darkening blinds to achieve a deep and restful sleep.
These small adjustments to your daily routine and sleeping area can go a long way toward ensuring an uninterrupted, restful night of sleep — leading to better health. If after using these steps you're still having trouble sleeping, you may need to make a few more changes. I share more strategies in my past article, “Top 33 Tips to Optimize Your Sleep Routine.”
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