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Are LED screens causing harm to the vision of computer users?

Mon, 04 Jul 2016 16:09:00
5 / 5 (3 Votes)
Article by:
Erik Peper, PhD
Double plot (2 x 24 hours.) of typical daily rhythms of body tempera-ture, melatonin, cortisol, and alertness in humans for a natural 24-hour light/dark cycle. Graph via Erik Peper, PhD.
Sleep has become more and more elusive since checking my cell phone before going to sleep.
Ouch, my eyes hurt when I flipped the light switch on and the room was flooded with light.
After working on my computer screen, the world looked blurry.
At night, the intense blue white LED headlights blinded me unlike the normal incandescent headlights.  
My eyes become irritated and dry after looking at the computer screen.
More and more people are myopic and wear contacts lenses.
Many older people are suffering from macular degeneration and may go blind.
 Migraine pain significantly decreased when a person looks at soft green light and significantly increased when looking at bright white light (Hamzelou, 2016)

Vision problems are becoming more and more frequent. More and more children are nearsighted and need vision correction, while macular degeneration — a major cause of blindness for older adults — is becoming more prevalent (Schneider, 2016).   As we look ahead into the future, a new epidemic is starting to roll in — compromised vision.  Major culprits include:
    1)    Near visual stress caused by looking intensely at surfaces or objects 1–2 feet away, such as computer screens, tablets and cell phones, inhibits the eyes to relax and increases nearsightedness (Fernández-Montero et al., 2015).
    2)    Absence of visual relaxation and shifting focus from close to far distance. This ongoing increased focus decreases blinking rate and exhausts the eyes.
    3)    Absence of looking at the green coloring of vegetation that historically predominated our visual environment — a color that is relaxing for the eyes and body, especially when seen from a distance.
    4)    Sleep suppression and disturbance caused by working/reading/watching LED screens —computer screen, tablet, cell phone, TV, or e-readers such as Kindle Fire, or any tablet — before going to bed Tosini et al., 2016). The blue light component produced by the LED screen suppresses melatonin production and interferes with sleep onset.
    5)    Extreme variation in light intensity damages the retina. The pupil, which normally contracts to protect the retina as light intensity increases, is too slow to respond to the sharp changes in light intensity. This is very similar to looking at the sun during a solar eclipse without eye protection.  The intense sunlight literally will burn/damage the retina and can induce blindness.
    6)    Harmful exposure of the blue light component of the LED screens or light bulbs may increase inflammation and damage to the macular area of the retina. This is often labeled as toxic blue light with a wavelength of 415–455nm (Roberts, 2011).
The light that illuminates our visual world and how our world conditions us to use our eyes is totally different from how our eyes evolved over the previous million years. Although our present life is far removed from our evolutionary past, that evolutionary past is embedded within us and controls much of our biology and psychology. Consider how we used to live for millennia.
I look up and see vultures circling. It is not too far.  I rapidly walk in the direction.  I have a sense where the possible food source could be.  As I walk I alternately look at the distance and close at the ground and scrubs.  I continually scan the environment. Although there are shadows where I look, the light is of somewhat similar intensity unless I look directly at the sun.  While doing tasks, I focus ahead where I will plant my feet, or at my food, or objects my hands are manipulating. I alternately shift from foreground to background. As I look in the distance and see the many green plants, my eyes relax.
In the morning, the natural light wakes me.  The bright morning light wakes me, I stretch and move.  As the day progresses the light becomes brighter; then at sunset the light becomes softer and the yellow orange red spectrum predominates.  

Whether we lived twenty thousand years ago in caves or communities, or two hundred years ago in small houses in cities or farms, sunlight illuminated our world. The sunlight warms us, is necessary for vitamin D production, and controls our biological circadian rhythms. Sunlight, and sometimes moonlight, provided the only source of illumination. Generally, we woke up with the light and went to sleep when the light disappeared. For thousands of years, humans have attempted to bring light to darkness to reduce danger. Light produced by fire for cooking and for protection against predators, and some form of oil lamps provided minimal illumination. These light sources were predominantly red and yellow. It was only with the application of gas and electrical illumination that lights became brighter. Usually, the light transitions were slow and gentle, which allowed the ciliary muscles of the iris to contract, thus making the pupil much smaller and reduced the influx of light to the retina, thereby protecting the retina from excessively fluctuating light intensity.
Exposure to light in the evening or night is very recent in evolutionary terms. For hundreds of thousands of years, the night was dark as we hid away in caves to avoid predators. The darkness allowed our eyes to regenerate. Only in the last few thousand years did candles or oil lamps with their yellow orange light illuminate the dark. Fear of the dark is primordial — in the dark we were the prey. During those prehistoric times, our fear was reduced by huddling together for warmth and safety as we slept. Now we turn on a nightlight while sleeping to feel safe, or to allow us to see in case we need to get up. For many of us, darkness still feels unsafe, and from birth, that fear became amplified by sleeping alone in a crib without feeling the tactile signals of safety provided by direct human contact.
Most people now live and work indoors, and we are no longer exposed to direct or indirect sunlight.  Instead, we can illuminate our work and personal world 24 hours a day, and total darkness is elusive.  Even when I close the shades in my bedroom, the blinking light of the smartphone charger, and the headlights of cars passing by penetrate the darkness. Upon entering a dark room, we throw the switch and the room instantly is flooded with light.  This instant transition to full light pains the eyes as the eyes struggle to adapt by closing the iris.  The retina was already impacted. Could this be one of the covert factors that contribute to the development of macular degeneration?
Historically, we mainly looked at reflected light and almost never at the light source — such as at the sun. Now we predominantly look directly into the light source of the light bulb, TV, computer, laptop, e-readers and smartphone screens. We are unaware that the light we see is not the same type of light as natural sunlight.  It still appears white; however, that is an illusion.  We live most of our lives indoors and illuminated by incandescent, fluorescent and LED light sources. These lights have limited spectrums and may lead to light malnutrition and blue light poisoning.
The most recent change has been the use of light-emitting diode, or LED — an electronic semiconductor device that emits light when an electric current passes through it. This is the process of flat TV, computer, tablet, cell phone screens and LED light bulbs. These bulbs are highly energy efficient and thus are being installed everywhere, but are a significant health hazard — which is described superbly and in detail by architect and lighting expert Milena Simeonova at www.lighting4health.com.
What can you do to protect your eyes and improve your vision?
Use your eyes as much as possible in the manner that was dong throughout most of our evolutionary history; this means:
    1)    Read and implement the practices described in the superb book, Vision for Life: Ten Steps to Natural Eyesight Improvement, by Meir Schneider, which has helped thousands of people maintain and improve their vision.
    2)    Take many vision breaks and look away from your screen. If possible look at the far distance and at green plants and trees to relax your eyes.
    3)    Do NOT use an LED e-reader; instead, use e-readers that can be read by reflective light such as a Kindle paperwhite e-reader.
    4)    Block direct intense light sources. Arrange them so that they illuminate the walls and  you only see gradual light gradients of reflective light.
    5)    Install warm LED lighting — particularly for evening time — which has much less damaging blue light.
    6)    Install software such as flux on your computer that automatically adjusts your screen’s color-temperature depending on the time of day and your location. Thus, when the sun sets, the colors of the screen change and become more yellow, orange, and red — thereby reducing the transmitted blue light (Robinson, 2015).
    -     Mac, Windows, and Linux computers: Flux is a free application at https://justgetflux.com/.
    -    Android or iPhones: install a “blue light filter” application.
    7)    Spend as much time as possible looking at far distances with soft green light backgrounds.
    8)    Encourage children to play outside, and do not allow young children to entertain themselves with screen time, especially when the eyes are developing (See my 2011 blog: Screens will hurt your children).
    9)    Limit screen time and increase movement and physical activity time.
    10)    Blink — and blink more — and relax your eyes. When visually stressed, blinking is inhibited because you do not want to miss the tiger who potentially could attack you. That is our evolutionary response pattern; however, there are no life threatening tigers around; thus allow yourself to blink. Do the following exercise to experience how your eyes change depending how you open and close them.
How to increase stressed dry eyes:
Sit comfortably, letting your eyes close, and breathe.  Then exhale, and when ready to inhale, inhale rapidly into your upper chest while opening your eyes wide — as if fearful and frightened. Repeat a second time, and then keep holding your eyes wide open as if looking for danger.
Observe what happened.  Most people experienced that the front of their eyes felt slightly cooler, as if a slight breeze were going over the cornea, and the eyes (cornea) are drier.
How to increase relaxed moist eyes:
Sit comfortably, letting your eyes close, and breathe.  While breathing, allow your abdomen to expand when you inhale, and gently constrict when you exhale, as if the lungs were a balloon in your abdomen. When ready, inhale while keeping the shoulders relaxed and the eyes still closed, and then gently begin to exhale and very slowly and softly open your eyes slightly, while looking down peacefully and content — just as a mother may look down upon their baby in her arms with a slight smile. Repeat a second time, and gently open your eyes slightly as the exhalation has started and is softly flowing.
Observe what happened.  Most people experienced that their eyes became softer, more relaxed with an increase in the beginning of a tear beginning to fill the front of the cornea.
You have a choice! You can mobilize health or continue to risk your vision. Adapt the precautionary principle and act now.  See the in-depth description of the potential harm of LED lights described by architect and lighting designer Milena Simeonova who helps people stay healthy by applying natural light patterns inside buildings (www.lighting4health.com).
LED Lighting and Blue Light Hazard  [Milena Simeonova, architect, MS in Lighting, LRC, IES, LC]
When TVs, computers, tablets, and mobile devices are used in the evening hours, the cool LED light emanating from the screens shifts the body onset for melatonin production, pushing back our bedtime by 1 1/2 hours or later. You may think that is not so bad if you have to study for exams or deliver a final project. However, think twice when disrupting the circadian system and depriving your body of normal sleep hours. It is a recipe for initiating illness. Watch a superb TEDxCambridge 2011 lecture, “A Sleep Epidemic,” by Charles Szeisler, PhD, MD  from Harvard Medical School.
Science has discovered that blue light suppresses melatonin — the sleep hormone — and can either regulate or deregulate our circadian system, or bio-clock, disrupting our sleep during the night and lowering our performance during the day. It affects our normal body function that is synchronized with the daylight-night cycle, as shown in Figure 1. If this cycle is disrupted, poor health can follow in the form of heart disease, cancer, depression, obesity, or other illnesses.
Our circadian system regulates the body’s endocrine and hormonal production; these functions are synchronized with the cycle of day-night in nature. A healthy body starts producing melatonin at about 7 p.m., and melatonin, the sleep hormone, peaks from 12 a.m.–3 a.m. From: van Bommel, W. J. M. & van den Beld, G. J. (2003). Lighting for work: visual and biological effects. Philips Lighting. p.7.
What about the change from incandescent to LED light in the room? With LED lighting, the Blue Light Hazard has increased, particularly from high output cool LED light fixtures with clear lens. LED lighting is produced from a blue LED chip combined with warm phosphors; think of it as a blue spike with a warm tail, as shown in Figure 2. The trouble with the blue spike is that it peaks at about 430nm–440nm, and science has found that light below the 440nm wavelength frequency results in macular degeneration in older people (Roberts, 2001). For more details, see chemistry professor Joan E. Roberts from a Fordham University presentation, “How does the spectrum of light affect human health?
The Figure 2 graph shows cool LED light with a blue light spike — a large output of blue light — and a small tail of warm phosphors. On the right is a warm LED light with decreased blue light output. [From: Floroiu, V.A. (2015]
The health risk is even greater for younger eyes — ages 20–40 — because older eyes are more protected with the natural aging of the eye lens that is thickening and yellowing, which in turn scatters blue light and protects the eye retina from energy absorption. In contrast, the younger eyes allow 2–3 times more transmittance of blue light, resulting in higher ocular oxidation and greater risk of retinal photo-degradation (Hammond et al., 2014). Thus, in a room with cool LED lighting — above 4,000K — there will be a lot of blue light that can be damaging to the eye retina. This is particularly true when eyes have direct exposure to high-output LED fixtures that cannot be dimmed.
This is just the tip of the iceberg. LED lighting has other potential health issues — such as flicker that is barely discernible at full light output, but increases when dimming the lights — or the spatial flicker resulting from gazing along bright LED lights in a room, or the multifringed or multiple shadows of a single object that are projected from the multiple LED chips in a fixture, which is unnatural and is not observed in nature. It is important to choose LED lighting that maintains human health, such as at this link: https://www.greenbiz.com/blog/2010/01/21/pendulum-energy-efficiency-and-importance-human-factors).
Interactive dynamic lighting is also on the rise, and this has unintended effects on the autonomous nervous system, with overstimulation of the sympathetic neural system, disrupting the balance of arousal and rest that is needed for people to stay healthy.

How can we protect our health? We can use 4,000K LED light for daytime, use warmer lights 3000K and below for the evening hours, and as a nightlight use a warm or amber color light; get blue light filter applications for your screens; dim your room lights in the evening; use LED lights that have a diffuse lens shade to soften the light beam; aim LED lights to the ceiling or wall surfaces, and away from the eyes; and best of all – get plenty of healthy daylight during the day.
The mechanism of blue light hazard — BLH
Blue light is also known as “cool” light, which has a high frequency of oscillation, due to high excitation of light particles, or photons. The blue photons have smaller mass, and carry significantly higher energy than the red light photons; blue photons can create oxidative photodegradation in ocular tissues, and suppress effectively melatonin and disrupt sleep even at a very low level.
The colors of a rainbow illustrate the visible light spectrum. Each color represents a specific light frequency, vibrational energy, wavelength, and excitation. Light wavelength can be for the benefit or to the detriment of human health, depending on the dosage or length of exposure to the particular wavelength of light; depending on the timing or when exposed to light.
The visible light spectrum ranges from 360nm to 760nm wavelengths, with red light at 620–750nm having the longer wavelength and smaller excitation, and blue light at 420–490nm having a short wavelength with high frequency — or more pulses per time cycle.
Anyone who wishes to see more information on this subject can contact the following:
Milena Simeonova, Architect, MS in Lighting LRC, IES, LC
    1658 8th Avenue, San Francisco, California 94122, USA
    T: 415-684-2770; Light4Health, www.lighting4health.com
Help people stay healthy by applying Natural Light Patterns, and the principle of less is more, in calm and nurturing places.
Dr. Peper is a professor at San Francisco State University and can be contacted by email at epeper@sfsu.edu. His website is www.biofeedbackhealth.org, and he has a blog at www.peperperspective.com.
List of References:
    Hamzelou, J. (2016).  Green light eases migraine pain – but we don’t know why.  New Scientist. 19 May 2016. [https://www.newscientist.com/article/2089062-green-light-found-to-ease-the-pain-of-migraine/]
    Fernández-Montero, A., Olmo-Jimenez, J. M., Olmo, N., Bes-Rastrollo, M., Moreno-Galarraga, L., Moreno-Montañés, J., & Martínez-González, M. A. (2015). The impact of computer use in myopia progression: A cohort study in Spain. Preventive medicine, 71, 67-71.
    Hammond, B. R., Johnson, B. A., & George, E. R. (2014).Oxidative photodegradation of ocular tissues: beneficial effects of filtering and exogenous antioxidants. Experimental eye research, 129, 135-150.
    Roberts, D. (2011).Artificial Lighting and the Blue Light Hazard. Posted in: Daily Living. Retrieved June 18, 2016.
    Roberts, J. E. (2001). Ocular phototoxicity. Journal of Photochemistry and Photobiology B: Biology, 64(2), 136-143.
    Robinson, M. (2015). This app has transformed my nighttime computer use. TechInsider, Oct. 28, 2015. http://www.techinsider.io/flux-review-2015-10
    Schneider, M. (2016). Vision for Life: Ten Steps to Natural Eyesight Improvement. Berkeley, CA: North Atlantic Books. ISBN-13: 978-1623170080
    Tosini, G., Ferguson, I., & Tsubota, K. (2016).ffects of blue light on the circadian system and eye physiology. Molecular vision, 22, 61.
    Van Bommel, W. J. M. & van den Beld, G. J. (2003). Lighting for work: visual and biological effects. Philips Lighting.

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