Even though sunlight is free, we pay for electric lightbulbs. We enjoy access to light 24 hours a day, even lighting the outside at night. The miracle of electric lighting means more leisure and work time.
What effects do the different types of lightbulbs have on our eyes? On our health? Does the type of light in the evening affect our sleep cycles? We’re encouraged to use compact fluorescent and LED bulbs instead of incandescent bulbs, but are the long-effects of these new bulbs known, or can their effects be predicted?
Kinds of light
At one end of the spectrum of light is low frequency infrared light, invisible to the naked eye, but visible to infrared camera devices. We experience infrared light as heat. Next is the visible spectrum, from violet through blue and green and yellow to red. The light with the most energy is shorter wave ultraviolet (‘long’ wave UVA and short wave UVB). The shorter the wave length of light, the greater the energy it contains. This is why UV light is so damaging to skin and eyes.
From the sun
- Infrared – beyond red, and although “invisible,” the retina can perceive it, as when it is pulsed rapidly in laser light pointers.
- Visible light – this includes blue light, which is poorly blocked by the eye’s pigmentation.
- UVA – long wave ultra violet; it penetrates deep into the skin.
- UVB – short wave ultra violet; it burns the superficial layers of the skin, and is part of vitamin D production process.
From light bulbs
- Incandescent bulbs are similar to daylight but are higher on the red end of the spectrum. They emit just a little blue light.
- Florescent & compact florescent – energy efficient but contain mercury.
- Range in color from cool-white with higher proportion of blue, through daylight to warm-white; they emit a small amount of UV radiation.
- Tanning lamps, UVB medical lamps, etc. emit UVA and/or UVB
- Grow lamps – more in red/blue range absorbed by chlorophyll.
- Halogen – near full spectrum UV to near infrared, emit UV, only a little blue light.
- Intensely powerful can be very small.
- Get very hot, increased fire risk.
- Often have a UV absorbing filter to absorb UV
- Do not contain mercury
- LED – more blue light than incandescent bulbs.
- “Full-spectrum” – these bulbs supposedly deliver a full spectrum of visible light, but this is more of a marketing term than anything else. The spectrum displayed is not evenly distributed, and may not be much different than non “full-spectrum” bulbs.
- Computers and handheld devices emit blue light.
Healthy versus dangerous light
Ultraviolet light harms both skin and eyes. It especially damages the cornea and retina. The damage accumulates and causes cataracts, pinguecula and pterygium.
Blue light damages the retina and the photoreceptors because this wave length penetrates all the way to the back of the retina. The net result is oxidative damage to the tissues of the eye
Actually, it is blue-violet light that is the most harmful. In 2008 Essilor, in partnership with the Paris Institute identified a narrow band of visible light, blue-violet, which causes the most harm to the retina.1
Blue-turquoise light is essential for our vision. It helps maintain our sleep cycle and plays an important role in overall health.
Red light and green light support skin health and are used in some medical therapies.
Near-infrared light (NIR) is missing from LEDs. NIR light helps the cells produce energy and helps the cells in the retina repair and regenerate. The mitochondria in the cells contain chromophores. Chromophores are light-absorbing molecules. They allow infrared-A light to be absorbed about an inch into the tissue. The radiation is a crucial part of producing adenosine triphosphate (ATP), which is cellular energy. Without ATP, your cells would not function.
The sun emits light on the near-infrared spectrum. So do halogen bulbs and incandescent bulbs. Special near-infrared saunas can be used for wound healing and other health applications.
LEDs produce no infrared radiation. The long-term consequences of reduced near-infrared light on health remains to be seen.
Blue/blue-violet light harm vision
Blue Light Increases Cataract Risk
Excessive exposure to blue light is a known risk factor for developing cataracts. Seniors by far suffer the most cases of cataracts. Today’s seniors have several strikes against them regarding blue light exposure:
- Until they were warned of the thinning ozone layer and the need for sunglasses, many got a large exposure of blue light from the sun.
- May have had an outdoor career.
- Spent more time recreating outdoors than more recent generations.
- Damage from blue light is cumulative and adds up over a lifetime.
- Average American looks at TV, tablet, computer and phone screens 10 hours per day.2 These devices emit blue light.
- A lifetime of poor eating habits and insufficient antioxidants catches up with them. Antioxidants such as carotenoids in brightly colored vegetables fight cataracts. Additionally, seniors generally have less efficient digestion and may have less ability and motivation to prepare nutritious meals.
Given these risk factors, it’s not surprising that more that 1 in 6 Americans over 40 have cataracts. By age 75, the figure is 1 in 2.3
Cataracts can start forming in middle age. People of all ages need to limit their blue light exposure. In the past, we mostly got blue light directly from the sun. Now we have indoor lights or electronics on most of the time. This is why light bulb choices are important to help prevent or reduce cataracts.
Note: If the cataract is severe enough, cataract surgery may be recommended. The newest artificial intraocular lenses may have built-in UV protection, or they may have blue light protection.
Blue Light Increases Macular Degeneration Risk
Blue Light Increases the Risk of Eye Cancer
Blue light exposure increases the risk of cancer of the eye.7
Blue Light Makes It Harder to Fall Asleep
Humans are diurnal – active during the day. Widely available electric indoor lighting has stressed our bodies. Staying up late with lights on, watching TV, and using electronics disrupts our natural sleep/wake cycles. These large amounts of blue light tell the body to stay awake.
Our 24-hour circadian rhythm lets us function well in our environment. When we are exposed to darkness, we produce a hormone called melatonin. Melatonin makes us fall asleep. After sufficient sleep, another hormone called cortisol is triggered to wake us up. The strongest environmental cue for sleep is an absence of short-wave blue light.
Most people with Seasonal Affective Disorder (SAD) find relief from blue light exposure in the morning. Sitting in front of special full-spectrum bulbs soon after waking up helps regulate the body’s hormones. Using these bulbs at night can disrupt sleep.
Lamp Types and Health Risks
Danger of LED Lightbulbs
Flicker. Because LEDs are digital lights, they flicker. Most people cannot perceive this. Color-changing LED lights and dimmed LED lights turn completely off and completely on, very quickly. Flicker is “biologically active. And flicker is something that is very harmful to your [biology],” according to Dr. Alexander Wunsch, an expert on photobiology.8 Old TVs had noticeable flicker; modern flat screens still have flicker, but it is much faster.
Blue Light. LED lights emit substantial amounts of blue light, and their emission of light is high intensity. Researchers in France wrote that these factors “are the main sources of concern about the health risks of LEDs with respect to their toxicity to the eye and the retina.” 9 They conducted a peer-reviewed animal study. After exposing rats to commercially available white LEDs and four kinds of blue LEDs, they examined the animals’ retinas. They discovered that the lights caused oxidative damage, injury and cell death to the retinal cells and photoreceptor cells.
Toxins: Although LED lights do not contain mercury, they do contain lead, arsenic and a number of other toxins and heavy metals. The low-intensity red LEDs were found to contain up to 8 times the safe levels of lead.10
Danger of Florescent Lightbulbs
Wavelength. May interfere with circadian rhythms due to suppression of melatonin, which in turn has been linked to cancer. Warm white does this the least, and so is recommended for night time use.
Flicker. May cause problems for people who are sensitive to light, such as 21% of people with chronic fatigue or Lyme disease. Some newer lamps have less flicker problems.
Ultraviolet light. The ‘double-envelope‘ compact fluorescents, which look like a regular light bulb, are ok. But exposure over an hour to unshaded ‘single-envelope’ compact lamps can exceed radiation guidelines. These are the bulbs that show the spiral shaped bulb. 3 to 6 hours exposure daily is equivalent to a 10% to 30% exposure to carcinogenic radiation.
In addition, in product safety testing, some of these single-envelope CFL’s were found to have cracks in the phosphor coating – which might permit UV leakage. Avoid this by buying only double-envelope CFLs.11
Eye Harm. Cataract risk is increased by exposure to ultraviolet light. But provided lamps are a safe distance (more than 30 cm), there should be little increased risk.
Electromagnetic risk. The electronic ballasts emit electro-magnetic fields in low frequency range and have been classified as possibly carcinogenic. Bulbs with high frequency ranges pose more risk, but again, not being too close makes a difference.
Mercury. Always follow safety guideline for cleaning up and disposing of fluorescents since they contain mercury. The amount of mercury is small compared to, for example, a single dental amalgam filling.
Other. There are anecdotal reports, but insufficient research connecting fluorescents and compact fluorescents with other conditions like migraines and autism.
Best Practices for Healthy Lighting
You can counteract negative lighting trends with a few simple changes.
Sleep: To get better sleep, avoid blue light 1 to 2 hours before bedtime.
- Turn off all screens and electronics as bedtime approaches (1-2 hours before).
- Stay in rooms lit by halogen lamps that use DC (direct current). Or light the room with clear incandescent bulbs.
- Read a paper book or magazine. The Kindle Paperwhite emits no blue light.
- Maintain a consistent bedtime routine and a set sleep schedule. This trains your body to fall asleep and stay asleep.
- If you have trouble sleeping, consult your doctor.
- While lighting by candle eliminates problems with bulbs, it is a fire hazard.
- Wear blue-blocking glasses after the sun sets (see details below).
Indoor Lighting at Work: You may have limited control over your lighting. If you can, use a clear incandescent bulb. Or get a halogen lamp powered by DC (direct current). If you must use CFLs, use warm-white, double-envelope CFLs. Try to sit next to a window.
Indoor Lighting at Home: Choose a home with plenty of windows and, if possible, skylights. Windows and skylights can be added to existing homes. If your lights are on during the day, and you are often home, favor clear incandescent bulbs and halogen lamps powered by direct current. Go outside more often.
In the evening, try to avoid LED lights and CFLs. If you use CFLs, then favor warm-white rather than cool-white, and buy only double envelope CFLs.
Street Lighting: Your local government may be considering installing LED lighting outdoors. The American Medical Association (AMA) warned in 2016 that LED streetlights have harmful human and environmental effects. They said LED lighting has worse nighttime glare and are intense enough to decrease visual acuity and safety. The AMA also said that white LED lights are five times more damaging the circadian sleep rhythms than other street lamps.
Smartphones and Tablets: Your device may include blue-blocking software. Activate it and set it to turn on in the evening. Or, download an app for free or for a small fee. Turn on dim ambient light in the evening when using a handheld device. Otherwise, your iris opens too much, letting in excessive light from the screen.
Computers: Use software that filters out blue light and adjusts screen brightness, such as Iris – “Software for eye protection, health and productivity.” 12 Or, wear blue-blocking glasses.
Blue-Blocking Glasses: A very cheap solution is glasses that filter out blue light. They are orange or amber in color and cost as little as $10 on Amazon.13 Wear them between sunset and bedtime. If you are exposed to fluorescent or LED lights at work, wear the glasses to block the high-intensity blue light.
Seek Natural Light: Sunlight provides near-infrared radiation for cellular energy and blue light to help regulate your sleep cycles. Spend time outdoors. Wear UV blocking sunglasses most of the time when in the sun; a few minutes exposure to sunshine can be beneficial to eyes.
Humans evolved with only the sun and open fires for light. Harnessing light was a key achievement in developing civilization. Our modern world is light-filled, and most of our activities take place bathed in artificial light. Simple steps can protect our vision and health from potential hazards associated with certain types of lightbulbs.
Nutrition: Good nutrition is essential. You might consider adding basic protection for your vision with the carotenoid antioxidants contained in our Advanced Eye & Vision Formula. If you work much of the day on a computer you might also want to consider our computer fatigue combo package which adds a few more essential nutrients.
- Smick K et al, Blue light hazard: New knowledge, new approaches to maintaining ocular health. Report of a roundtable sponsored by Essilor of America. March, 2013, NYC, NY. ↩
- “Americans devote more than 10 hours a day to screen time, and growing” By Jacqueline Howard, CNN Updated 4:22 PM ET, Fri July 29, 2016 accessed 6/22/17 ↩
- National Eye Institute (NEI) https://nei.nih.gov/eyedata/cataract ↩
- P. Geiger, et al, Blue light-induced retinal lesions, intraretinal vascular leakage and edema formation in the all-cone mouse retina, Cell Death & Disease, November, 2015. ↩
- C. Grimm, et al., Rhodopsin-mediated blue-light damage to the rat retina: effect of photoreversal of bleaching, Investigative Ophthamology & Visual Science, February, 2001. ↩
- T. Narimatsu, et al, Blue light-induced inflammatory marker expression in the retinal pigment epithelium-choroid of mice and the protective effect of a yellow intraocular lens material in vivo, Experimental Eye Research, March 2015. ↩
- Patrick Logan, et al, Evidence for the Role of Blue Light in the Development of Uveal Melanoma, Journal of Ophthalmology, April, 2015. ↩
- How LED Lighting May Compromise Your Health. October 23, 2016. Dr. Mercola. Mercola.com. ↩
- Retinal damage induced by commercial light emitting diodes (LEDs). Jaadane I. et. al., Free Radical Biology & Medicine, July, 2015 ↩
- L. Seon-Rin, D. Kang, et al, Potential Environmental Impacts of Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity, and Hazardous Waste Classification, Environmental Science & Technology, December, 2010. ↩
- Environmental Health Perspectives, https://ehp.niehs.nih.gov/120-a387/ ↩
- https://iristech.co/ ↩
- https://www.amazon.com/Uvex-Blocking-Computer-SCT-Orange-S1933X/dp/B000USRG90 ↩