- Energy-saving light-emitting diode (LED) lights typically emit blue light that can generate high amounts of oxidative stress that contributes to visual deterioration if viewed at the wrong time of the day
- Excessive blue light, especially at night, can prevent the priming of your retinal cells for repair and regeneration, thereby raising your risk of vision problems, including age-related macular degeneration (AMD), a leading cause of blindness
- The risks of LEDs to your vision in particular are highlighted in a 282-page report issued in 2010 by the French Agency for Food, Environmental and Occupational Health and Safety (ANSES), which recommends limiting exposure to LEDs and avoiding LED screens before bedtime
- ANSES also recommends limiting household use to “warm white” LEDs and calls for reducing the luminosity of car headlights
- Children are at high risk for damage from LEDs due to the transparency of the lenses in their eyes
While this article focuses on light-emitting diode (LED) lights please understand that compact fluorescent light bulbs (CFLs) are far worse. Not only do they have the same digital light problems as LEDs but they also have mercury in them and cause dirty electricity in the 62 KHz range. If you have any fluorescent bulbs in your home you would be strongly advised to carefully replace them because if you break the bulb there are certain precautions you need to take to clean it up.
In fact, the U.S. Environmental Protection Agency has special rules for cleaning up broken CFLs, which include opening windows, airing out the room and shutting of the heat or air conditioning for several hours, so as not to disturb the leaked mercury. You also are to call your local government about proper disposal of the fragments — and when in doubt to call a poison control center.1
Energy-saving LED lights2 have several detrimental biological effects. For example, as explained by photobiology expert, Dr. Alexander Wunsch, in our 2016 interview (above), LED light:
- Emits aggressive blue light that can generate high amounts of oxidative stress that contributes to visual deterioration, and is devoid of near-infrared light that would help counteract some of that damage.
- Negatively affects mitochondrial function and may therefore exacerbate health problems rooted in mitochondrial dysfunction, including metabolic disorder and cancer.
- If viewed at night can suppress your melatonin production, thereby disrupting sleep, which can have far-reaching consequences for your health, including raising your risk of insulin resistance (which in turn raises your risk of myopia3 and many other conditions and diseases).
- Can prevent the priming of retinal cells for repair and regeneration (since it does not have any healing near-infrared frequencies), thereby raising your risk of vision problems, including age-related macular degeneration4 (AMD), a leading cause of blindness among people over 50. AMD refers to damage to the macula, a small spot near the center of the retina that’s needed for sharp central vision.
The risks of LEDs to your vision in particular are highlighted in two reports by the French Agency for Food, Environmental and Occupational Health and Safety (ANSES). The first one, a 282-page report5,6,7issued in 2010 (the full report8 is only available in French, but an opinion summary paper9 is available in English on anses.fr.), and a 400-page report10,11,12 issued April 2019, available only in French.
While separated by nine years, the conclusion of the second report appears to be unchanged from, and supports the opinion of the first. Considering incandescent light bulbs are being phased out both in the U.S. and European Union (EU), it’s important to understand the health ramifications of the replacements, which include LEDs. As noted by ANSES in 2010:13
“LED technology, which has certain advantages compared to other types of lighting (energy efficiency, life span), is changing rapidly. It has a wide range of applications including public, domestic and commercial lighting, sport facilities, indicator lamps (toys, signposting, etc.), vehicle lighting, and therapeutic products (light therapy).
However, the quality of the light emitted by these lamps (color temperature, color rendering index) does not always provide the same level of performance as other sources of lighting.
The intense wavelengths in the blue part of the spectrum of light emitted by some LEDs, and the associated radiation intensity, raise the question of new health risks related to these sources of light. In view of this situation, the Agency issued a formal internal request to assess the health effects of LED-based lighting systems.”
LED Light Is Photo-Toxic, French Assessment Concludes
According to the ANSES reports, exposure to intense blue LED light — such as that emitted from newer flashlights and car headlights — is phototoxic and capable of causing diminished sharpness of vision due to irreversible loss of retinal cells. “Warm white” LED lighting, however, was found to have weak phototoxicity, which is precisely what you would predict as it has far less blue light.
An American review14 published in 2016 echoes these findings, concluding LEDs with a wavelength below 455 nanometers in the blue light range is damaging to the eyes in the long term. This paper also addresses the impact of blue light on the circadian rhythm. The two issues — your circadian rhythm and vision — are actually closely linked.
In an email, lead author Gianluca Tosini told CNN15 “There are blue light photoreceptors in the retina that directly communicate with the brain circadian clock,” and that “exposure to light in the evening affect sleep and circadian rhythms mostly by inhibiting the synthesis of the sleep promoting hormone melatonin.”
As explained by Wunsch, certain retinal cells also produce melatonin that helps regenerate your retina during the night. If you use LED lights after sunset, you actually reduce the natural regenerative and restoring capacities of your eyes. Needless to say, with less regeneration you end up with degeneration. In this case, the degeneration can lead to AMD, which is the primary cause of blindness among the elderly.
On top of that, as you age, your retina accumulates fluorescent molecules called lipofuscin, which are sensitive to blue light. Janet Sparrow,16 Ph.D., professor of ophthalmic sciences at Columbia University, told CNN,17 “Early evidence suggests that this light sensitivity may lead to unhealthy optical responses over the long term.”
Brightness Density and High Proportion of Blue Light Identified as Core Dangers
As noted in ANSES’ English opinion summary from 2010:18
“Strong components in the blue part of the spectrum of light emitted by the LEDs, as well as the associated intensity of the radiation, raise the issue of new health risks related to these sources of lighting. Some scientific studies [Dawson et al., 2001, Ueda et al., 2009], based on laboratory experiments with blue LEDs conducted on monkeys, give reason to suspect a danger for the retina related to exposure to light-emitting diodes.
As a result of the analysis of the existing scientific literature and the information collected during the additional hearings, potential health issues related to the use of LEDs were identified.
Those of greatest concern, due to both the severity of the corresponding dangers and the probability of their occurring as a result of the increasingly widespread use of LEDs, relate to the photochemical effects of blue light on the eye and the glare phenomenon. They result from:
• the spectral imbalance in LEDs (high proportion of blue light in white LEDs)
• the very high luminance of LEDs (high brightness density per surface unit emitted by these very small sources).
The photochemical risk is associated with blue light, and depends on the accumulated dose to which the person has been exposed, which is generally the result of low intensity exposure repeated over long periods. There is a high level of proof of such a risk.
Evidence from human observation and experimental studies on cell cultures and various animal species has converged to demonstrate the specific toxicity of shortwave (blue) light to the retina.
Blue light is therefore recognised as being harmful and dangerous to the retina, as a result of cellular oxidative stress. There is a strong suspicion that blue light aggravates age-related macular degeneration (ARMD), based on converging observations on experimental models.”
The report also noted that the stroboscopic effects in some LED lights may induce headaches and visual fatigue, which could also lead to a higher risk of accidents.
High-Risk Groups Identified
ANSES identified the following population groups as being at particularly high risk from LED exposure, either because they are extra sensitive to the type of light emitted by LEDs, or because of their unusually high levels of exposure:
- Children, due to the transparency of the lenses in their eyes
- Those with aphakia, i.e., people who are missing a lens on one or both of their eyes, either due to a wound, ulcer, congenital anomaly or surgical removal
- Pseudophakics, i.e., those with artificial crystalline lenses, “who consequently either cannot or can only insufficiently filter short wavelengths (particularly blue light)”
- Light-sensitive individuals, including those with AMD and certain skin diseases, and those taking photosensitizing drugs
- Workers exposed to extreme levels of blue light, such as lighting installers, theatre and film industry professionals
Standards Need Adjustment
ANSES concluded the EU standard, NF EN 62471,19,20 set in 2009, which addresses the “photobiological safety of lamps and apparatus using lamps” in the wavelength range of 200 nm to 3,000 nm, is inadequate for LEDs for three reasons:21
- “The maximum exposure limits … used to define the Risk Groups are not appropriate for repeated exposure to blue light as they were calculated for exposure of one 8-hour day and do not take into account the possibility of exposure over an entire lifetime.
- It contains ambiguities concerning the measurement protocols for allocating Risk Groups: the same LED could be assigned to different Risk Groups if considered individually or if integrated in a lighting system, as the evaluation distance imposed by the standard could be different.
- It does not take into account the sensitivity of certain specific population groups (children, aphakics, pseudophakics, etc.)”
Among its many recommendations, to protect the general public and the workforce, ANSES suggested:
- Limiting the sale of LEDs for domestic use to “warm white” LED light bulbs and low-risk LED devices
- Limiting overall exposure to LEDs and avoiding LED screens before bedtime
- Reducing the luminosity of car headlights
- Regulating the installation of certain higher risk lighting systems such that they would be limited to “professional uses, under conditions in which risks can be prevented”
ANSES also suggested manufacturers should “design lighting systems in which beams of light emitted by LEDs cannot be seen directly,” to reduce intensity and glare, and recommended adaptations to the current standard on the photobiological safety of lamps to take the special characteristics of LEDs, their potential hazards and high-risk groups into account.
As far as I can tell, no amendments have been made to the standard in the years since ANSES report came out, which just goes to show how long dangers can be known without any regulatory action being taken, and why safety regulations cannot always be trusted as the final word on safety.
Can Blue-Blocking Glasses Help?
When it comes to the question of whether wearing blue-blocking glasses is a viable solution against all this blue light exposure, research findings are mixed.
A systematic review22 published in Ophthalmic and Physiological Optics in 2017, which included three studies with 136 participants, concluded there was “a lack of high quality evidence to support using BB [blue-blocking] spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.”
Others disagree. The Harvard Health Letter, published by Harvard Medical School, recommends the use of blue-blocking glasses in evening hours if you have a lot of bright lighting or use LED screens.23A number of studies have also found blue-blocking glasses impart valuable benefits, especially with regards to sleep quality. Following are a few examples:
• A 2006 study24 that found blue-blocking glasses “represent an elegant means to prevent the light‐induced melatonin suppression, adding that “Further studies are needed to show that these glasses … could facilitate adaptation to night work.”
• A pilot study25 published in 2010 did just that, finding the use of blue-blocking glasses during the day, along with blue-green light exposure at night, improved adaptation to night shift work by improving “sleep, vigilance and performance.”
• A 2009 study26 in Chronobiology International found wearing amber (blue-blocking) glasses for three hours before sleep for two weeks significantly improved sleep quality and mood compared to controls who used yellow-tinted (UV-blocking only) lenses.
• A 2015 study27 in the Journal of Adolescent Health found blue-blockers significantly attenuated LED-induced melatonin suppression in the evening and decreased vigilant attention and subjective alertness before bedtime” in 15- to 17-year-old males, leading the authors to conclude that:
“BB glasses may be useful in adolescents as a countermeasure for alerting effects induced by light exposure through LED screens and therefore potentially impede the negative effects modern lighting imposes on circadian physiology in the evening.”
Blue-Blocking Glasses May Help Relieve Eye Strain
Research28 published in 2017 also contradicts Cochrane’s assessment that no high-quality evidence exists showing blue-blockers can relieve eyestrain. Here, participants who wore short wavelength-blocking glasses during two hours of computer work exhibited less visual fatigue and had fewer symptoms of visual discomfort compared to those wearing clear lenses. As noted in this study:
“Light toxicity to the retina is well established and occurs when excess light exposure causes photochemical, photomechanical, and photothermal damage. Some groups have reported that short-wavelength light may be particularly hazardous to the retina.
For example, Kuse et al. found that visible light-induced damage in photoreceptor-derived cells is wavelength-dependent: short-wavelength light in the blue spectrum had a more severe toxic effect compared to either white or green light.
These findings are consistent with other studies showing that retinal damage induced by LEDs in animal models show similar wavelength dependence. Other groups have shown that this phototoxicity can be attenuated by blocking blue light in cell models6 and in animal models …
Some human studies have shown that chronic subthreshold exposure to blue light may, indeed, have clinically relevant consequences. For example, although short-wavelength light also has been shown to be important for setting circadian rhythms, excessive exposure to blue light also has been suggested to be a major cause of eye strain. Consistently, Isono et al. reported that short wavelength-emitting devices contribute to visual fatigue …
Numerous groups have explored the possibility that lenses that block short-wavelength light may reduce these health hazards. Ayaki et al. demonstrated that wearing short-wavelength light-reducing eyeglasses when using electronic devices at night improves sleep quality and increases overnight melatonin secretion.
Similarly, Ide et al. found that wearing short-wavelength light-blocking eyeglasses during intensive computer tasks reduces eye fatigue and symptoms of eye strain.”
A primary goal of this study was to test the hypothesis that blue-blockers lessen eyestrain in a North American population. High-blocking glasses performed better than low-blocking ones. In fact, “subjects wearing high-blocking eyeglasses had even less fatigue after compared to before the task,” the authors state, adding that:
“Overall, these findings supported our assertion that high-blocking glasses do, indeed, appear to attenuate eye fatigue associated with computer use, even after controlling for confounding variables, such as age, sex, and contact lens use …
These findings not only validated past studies that have reported that short-wavelength light-blocking eyewear may attenuate eye strain, but also extended these findings to a North American population.
In addition, although a formal double-blind study design is impossible given the nature of the experiment, our rigorous study design, including careful control of experimental conditions (e.g., monitoring subjects for the duration of the task, standardizing testing room conditions, testing subjects at roughly the same time of day), minimized the risks of potential confounding factors.”
For Optimal Health, Address Your Daily Light Exposure
In my view, there’s ample evidence and sound science showing cool white LED lighting is a bad idea, from a health standpoint. While it may save you a few dollars on your electric bill, it could significantly impact your medical costs, not to mention quality of life, in the long run.
However they should be fine in areas that are infrequently used. The majority of bulbs in my home are LED but the ones in areas that I use all the time — my bedroom, kitchen and bathroom — are all incandescent. The LEDs in other rooms are frequently left on accidentally by guests and cleaners and when they are they don’t cause loads of lost energy.
To learn more about the ins and outs of LEDs and what makes this type of light so detrimental, please listen to my interview with Wunsch, embedded at the top, or read through the original article. Light is a vastly underestimated health factor. It’s more important than people realize, especially for healthy vision and sleep.
The good news is this is an area where most people still have a great deal of control — at least until you can no longer purchase incandescent light bulbs. To optimize your daily light exposure, keep these four key considerations in mind:
1. Replace LEDs in key areas that have night lighting with incandescent light bulbs — In areas where you spend most of your time during the day and evening, such as your kitchen, bathroom, and bedroom, swap out your LEDs for regular incandescent light bulbs, and leave the LEDs for areas such as hallways, closets, garage and porch, where your exposure to them is minimal.
2. Get bright, natural light exposure during the day — To get good sleep, you need properly aligned circadian rhythms, and step No. 1 is to make sure you get a sufficient dose of bright light exposure during the daytime. Your pineal gland produces melatonin roughly in approximation to the contrast of bright sun exposure in the day and complete darkness at night.
If you’re in darkness all day long, your body can’t appreciate the difference and will not optimize melatonin production. Ideally, to help your circadian system reset itself, get at least 10 to 15 minutes of light first thing in the morning.
This will send a strong message to your internal clock that day has arrived, making it less likely to be confused by weaker light signals later on. Then, around solar noon, get another 30 to 60 minutes’ worth of sunlight.
3. Avoid blue enriched light at night — Melatonin acts as a marker of your circadian phase or biological timing. Normally, your brain starts progressively increasing the hormone melatonin around 9 or 10 p.m., which makes you sleepy. Somewhere between 50 and 1,000 lux is the activation range within which light will begin to suppress melatonin production.
However, wavelength is also important. Red and amber lights will not suppress melatonin while blue, green and white lights will. So, be sure to avoid the blue light wavelength after sunset. This includes artificial light, and light emitted by electronics such as your TV, computer and other electronic screens.
There are a number of ways to avoid blue enriched light in the evening depending on your lifestyle and personal preferences, including the following suggestions. You can also learn more by reviewing my 2014 interview with researcher Dan Pardi.
- Turn off or dim all lights after sunset, and avoid watching TV or using light emitting electronics for at least one hour before bedtime (ideally two hours or more).
- After sundown, shift to a low-wattage bulb with yellow, orange or red light if you need illumination. A salt lamp illuminated by a 5-watt bulb is an ideal solution that will not interfere with your melatonin production.
- If using a computer, smartphone or tablet, install blue light-blocking software like Iris,29 or use amber colored glasses that block blue light.30
4. Sleep in complete darkness — Once it’s time to go to sleep, make sure your bedroom is as dark as possible. Exposure to room light during sleep has been shown to suppress melatonin by more than 50 percent,31 but even a small amount of light can decrease your melatonin. Simply closing your eyes is not enough as light can penetrate your eyelids.
If blackout shades are too great an investment, a sleep mask can do the job for far less money. Also keep in mind that digital alarm clocks with an LED display could have a detrimental effect, so either swap out your clock, or cover the display.
Alternatives include a sun alarm clock, which wakes you up by gradually increasing the intensity of light, thereby simulating sunrise, or a talking alarm clock,32 designed for the visually impaired.