Are LED screens harming you?Posted: June 18, 2016
Sleep has become more and more elusive since checking my cellphone in bed.
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 near sighted and need vision correction while macular degeneration–a major cause of blindness for older adults–is becoming more prevalent (Fan et al, 2004: Lee et al, 2002;
Faber et al, 2015; Schneider, 2016). As we look ahead into the future, a new epidemic is starting to roll in—compromised vision. Major culprits include:
- Near visual stress caused by looking intensely at surfaces or objects one to two feet away such as computer screens, tablets and cell phones inhibits the eyes to relax and increases near sightedness (Fernández-Montero et al, 2015).
- Absence of visual relaxation and shifting focus from close to far distance. This ongoing increased focus decreases blinking rate and exhausts the eyes.
- 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 looked from a distance.
- Sleep suppression and disturbance caused working/reading/watching the LED screens (computer screen, tablet, cell phone, TV, or e-readers such as Amazon 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.
- 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 sun light literally will burn/damage the retina and can induce blindness.
- 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 last million years. Although our present life is far removed from our evolutionary past, our 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 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 sun light warm us, is necessary for vitamin D production and controls our biological circadian rhythms. The sun light and sometime the 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 human beings have attempted to bring light to the darkness to reduce danger. Light produced by fire for cooking and protection against predators, and some form of oil lamps to provide minimal illumination. These light sources were predominantly red and yellow. It was only with the application of gas and electrical illumination that lights could become 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 reduce the influx of light to the retina and thereby protected the retina from excessive 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. And, 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. The 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. These days, while sleeping we turn on a night light to feel safe or allow us to see in case we have to get up. For many of us, darkness still feels unsafe since as babies the fear was amplified as we slept alone in a crib without feeling the tactile signals of safety provided by direct human contact.
Now most people live and work indoors and we are no longer exposed to direct or indirect sun light. Instead, we can illuminate our work and personal world twenty four 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 the cars passing by penetrate the darkness. While 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. This may 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 the sun. Now we predominantly look directly into the light source of the light bulb, TV, computer, laptop, e-readers and smart phone screens. We are unaware that the light we see is not the same type of light as natural sun light. It still appears white; however, it is an illusion. We live most of our lives indoors 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 (LED)–an electronic semiconductor device that emits light when an electric current passes through it. This is the process of flat TV, computer, tablet, cellphone 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 at the end of the article by architect and lighting expert Milena Simeonova, www.lighting4health.com
What can you do to protect your eyes and improve your vision?
Use your eyes as much as possible as we did through most of our evolutionary history which means:
- 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.
- Take many vision breaks and look away from your screen. If possible look at the far distance and green plants and trees to relax your eyes.
- Do NOT use LED e-reader; instead, use e-readers that can be read by reflective light such as Amazon Kindle Paperwhite eReader.
- Block direct intense light sources. Arrange them so that they illuminate the walls and you only see gradual light gradients of reflective light.
- Install warm LED light (particularly for evening time) which have much less damaging blue light.
- Install software such 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 I(Robinson, 2015).
–Android or iPhones: install a “blue light filter” app.
–For additional free apps to protect your eyes from too bright screen light at night, see: http://sometips.wersjatestowa.eu/how-to-protect- eyes-from-too-bright-screen-light-especially-at-night/
- Spent as much time as possible looking at far distances with soft green light backgrounds.
- Encourage children to play outside and do not allow young children to entertain themselves with screen time especially as the eyes are developing (see my 2011 blog: Screens will hurt your children).
- Limit screen time and increase movement and physical activity time.
- 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 and let your eyes be closed 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 report that the front of their eyes felt slightly cooler as if a slight breeze was going over the cornea, and the eyes (cornea) are drier.
How to increase relaxed moist eyes:
Sit comfortably and let your eyes be closed and breathe. While breathing allow your abdomen to expand when you inhale and gently constrict when you exhale as if the lungs are 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 report that their eyes became softer, more relaxed with increased of 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
By 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 bed time by 1-1.5hr or later. You may think that’s not bad, if you have to study for exams or deliver this final project. Think twice when disrupting the circadian system and depriving your body of normal sleep hours. It is a recipe for initiating illness. Watch the superb TEDxCambridge 2011 lecture, A Sleep Epidemic, by Charles Szeisler, PhD, MD from Harvard Medical School (https://www.youtube.com/watch?v=p4UxLpoNCxU)
Science has discovered that Blue light suppresses melatonin (the sleep hormone), and can either regulate or deregulate our circadian system (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 follows in the form of heart disease, cancer, depression, obesity, etc. Figure 1: Double plot (2 x 24 hours.) of typical daily rhythms of body temperature, melatonin, cortisol, and alertness in humans for a natural 24-hour light/dark cycle. 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 7pm and melatonin (sleep hormone) peaks at 12am-3am. 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 (see 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 detail, see Chemistry Professor Joan E. Roberts from Fordham University presentation, How does the spectrum of light affects the human health? http://www.be-exchange.org/media/ByLightofDay_Presentation.compressed-1.pdf
Figure 2: Actual measurements with LED Spectrometer of color tuning LED light source. On the left is cool LED light with big Blue light spike (big output of Blue light) and a small warm tail of phosphors. On the right is a warm LED light with decreased Blue Light output. From: Floroiu, V.A. (2015). The ABCs of truly energy efficient LED lighting. https://www.linkedin.com/pulse/abcs-truly-energy-efficient-led-lighting-victor-adrian-floroiu
The health risk is even greater for younger eyes (ages 20-40) because the 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 lighted with cool LED lighting (above 4000K), 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 are non-dimmable.
This is just the tip of the iceberg, as 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 the gazing along bright LED lights in a room; or the multi-fringed or multiple shadows of a single object, projected from the multiple LED chips in a fixture, that is unnatural and not observed in Nature. It is important to choose LED lighting that maintains human health. (See: https://www.greenbiz.com/blog/2010/01/21/pendulum-energy-efficiency-and-importance-human-factors)
Interactive and dynamic lighting are also on the rise, and will have unintended effects on the Autonomous Nervous System (ANS) with over-stimulating 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? For now, use 4000K LED light for daytime, use warmer lights 3000K and below for the evening hours; use as night light warm or amber color light; get blue light filter apps 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 also known as “cool” light, has a high frequency of oscillation, high excitation of its 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 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; and depending on the timing or when exposured to light.
Visible light spectrum ranges from 360 nm to 760 nm wavelengths; with Red light (620-750 nm) having the longer wavelength and smaller excitation, and Blue light (420-490 nm) having a short wavelength with high frequency (more pulses/time).
Contact information for 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
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/
Faber, C., Jehs, T., Juel, H. B., Singh, A., Falk, M. K., Sørensen, T. L., & Nissen, M. H. (2015). Early and exudative age‐related macular degeneration is associated with increased plasma levels of soluble TNF receptor II. Acta ophthalmologica, 93(3), 242-247.
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, 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