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What is the blue light from our screens really doing to our eyes?

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An eye doctor says he’s recently seen a few 35-year-old patients whose lenses, which are typically clear all the way up until around age 40, are so cloudy they resemble 75-year-olds’. A sleep doctor says kids as young as toddlers are suffering from chronic insomnia, which in turn affects their behavior and performance at school and daycare. A scientist finds that women who work night shifts are twice as likely to develop breast cancer than those who sleep at night.

What do all these anecdotes have in common? Nighttime exposure to the blue light emanating from our screens.

You’ve probably heard the hype these past few years: being in the presence of light at night disrupts the body’s natural circadian rhythms by suppressing the production of melatonin, a sleep hormone. But melatonin does far more than help us get sleepy – it’s also an antioxidant that appears to play a pivotal role in slowing the progression of cancer and other diseases.

“I’ve been spending a lot of the past 20 years worrying about it,” said Dr. Richard Hansler, who clocked in 42 years at GE Lighting developing “all kinds of bright, beautiful lights” before his move to John Carroll University in Ohio, where he studied the effects of light at night on our health. It was the mid 1990s, and at that point, he said, his concern wasn’t widely shared.

“I discovered that using light at night is bad for people’s health and interferes with their sleep. I felt a moral obligation to do something about it, particularly when I learned it’s the blue component in ordinary white light that is suppressing the production of melatonin. And melatonin not only helps you sleep but is a marvelous material that has a very big influence on health in general; specifically, if you don’t have enough you may develop diabetes, obesity, heart disease, and even a couple kinds of cancer.”

When the stars go blue

The impact of blue light on melatonin production was only recently confirmed, in 2001, when scientists found that light in the blue spectrum — the 415 to 445 nanometer range — disrupts melatonin. Because it is so bright, blue light is used widely in pretty much all LED devices, including phones, tablets, laptops, and TVs. And because it is so hot, it appears to be wreaking all sorts of havoc on our eyes, on melatonin, and consequently, on our health.

The latest research, in fact, overwhelmingly suggests that delayed production of melatonin due to blue light exposure at night is causing far more problems than insomnia, from diabetes and certain types of cancer to lupus and migraine headaches. Optometrists are even seeing high levels of retinal stress in young people that could lead to the early onset of macular degeneration, which in extreme cases can cause near blindness.

Image (1) nightlights.jpg for post 75505

“Here’s what doesn’t need research: 415 to 445nm is super hot light, and if it’s really focused and brought up close – when you’re talking about a tablet six inches from a kid’s face – it’s got to be significant,” said Dr. William Harrison, a renowned optometrist in Laguna Beach, Calif., who has been following the research on blue light closely for the past year. He said the research is compelling, but that the medical profession is slow to catch on to the concerns.

Because artificial light at night has only been around for the past century or so, and the hotter, brighter blue light has only been so heavily concentrated in our light sources for the past 10 or 20 years (the previously popular incandescent bulbs don’t emit the same amount of blue light, which is stronger in CFLs but stronger still in LEDs), its long-term effect on our eyes and bodies remains unknown.

Screening for problems

For those who like to read the scientific literature directly, here’s a quick tour of some of the latest findings, and a search on blue light and melatonin via the U.S. National Library of Medicine’s PubMed search tool can yield larger results:

  • Room light not only suppresses melatonin production, but it could also impact sleep, thermoregulation, blood pressure and glucose homeostasis
  • Blue light is considered a “carcinogenic pollution” that in mice correlates with higher cancer rates
  • A lack of melatonin is linked to higher rates of breast, ovarian, and prostate cancers, while blocking those blue rays with amber glasses is linked to lower cancer rates
  • Exposure to blue light in people appears to have an impact on mood
  • Lower melatonin in mice is linked with higher rates of depression
  • Too much light exposure can cause retinal toxicity
  • Blue light exposure may be playing a role in the higher incidence of cataracts and macular degeneration seen today

The more Hansler conducted his own investigation into the impact of blue light on various aspects of human and animal health, the more he felt he had an obligation to do something. In 2005, he and a group of physicists at John Carroll University developed light bulbs that don’t emit blue light and goggles that block out that part of the spectrum, and he has since written a handful of books on the subject. (If you’re doing the math, yes, Hansler is now 90 years old and no, he hasn’t yet retired.)

A few developers of goggles and glasses that block blue light exist now, including Lighting Science out of Florida. In fact Dr. Michael Breus, the “Sleep Doctor” who regularly appears on shows like Dr. Oz, is so convinced by the science that he’s bought Lighting Science’s Good Night Bulb (with low levels of blue light) for his bedroom and the Awake & Alert Bulb (with more blue light to energize in the mornings) for his bathroom. Astronauts even use the bulbs to help regulate their sleep cycles on the International Space Station, which orbits the Earth every 90 minutes.

It remains unclear whether our screens themselves will soon emit less blue light — Hansler is pessimistic because he says that changing the amoung of blue light will be like admitting that the screens are causing health problems, and lawsuits could ensue. For now, there are screens for tablets that purport to filter out the blue light, and as well as apps that let you put your device in a bedtime mode where the light contains less blues and more ambers. Hansler is suspicious of whether those screens and apps work, and wants more research done.

In the meantime, does this mean we all need to refrain from any TV or lighting at all in a bedroom in the hour or two prior to bedtime, in a room so dark you can’t see your hand in front of you? “I think that’s crap,” Dr. Breus says. “If I told everybody to put themselves into a pitch dark room at 8 at night at 68 degrees with no noise, would people sleep better? Maybe. But you have to have a fairly decent amount of light and in close proximity.”

Featured photo courtesy Shutterstock user kryzhov.

59 Responses to “What is the blue light from our screens really doing to our eyes?”

  1. SheridanZhoy

    Windows 8’s Magnifier tool makes it super-easy to invert the colors of the display, turning all that glowing white into a harmless black. Just enable it under Magnifier’s settings; you can use it even without actually magnifying the screen, and you can have it start-up automatically with your computer. I do this for all my text-centric activities. This may also be available in older versions of Windows.

    An alternative is switching to Windows’ “High Contrast” theme: handy, because you don’t have to turn it off for image-based activities, but the downside is it doesn’t work for most non-Microsoft software, like Google Chrome (though, Chrome does have its own high-contrast theme).

    And long live flux!

  2. “Here’s what doesn’t need research: 415 to 445nm is super hot light”

    I think it’s not hot, but cool. Red is hotter as it’s reaching the infrared spectrum.

    • normscleansingfire

      What they mean by ‘hot’ is ‘high energy’. Blue wavelengths of light are higher energy particles, meaning they transfer more energy per photon. This is why when flames are at their hottest they radiate blue light, and only as they cool do they radiate yellow, red and then infra-red light.

      It’s also why UV light and Gamma radiation are more dangerous to tissues than infra-red and radio waves. We feel infra-red light as being ‘hot’ because its energy is absorbed by the water in our tissues, and our nerves detect this increase. Other wavelengths of light have the same effect, and the same number of photons incident on a surface will effect different rates of energy transfer based on their wavelength. We just don’t encounter them quite as often.

  3. BlindAsABat

    “hotter, brighter blue light has only been so heavily concentrated in our light sources for the past 10 or 20 years” I call BS! Electric welding produces much higher energy light, including all the worst of UV, and has been around a lot longer than 20 years. Get your facts straight.

    • You are not very bright, are you… Pun not intended :-) “heavily concentrated in our light sources” Welding has been around for a while, but it has never been a significant source of light in most people lives, especially at night. They have their facts straight. You, on the other head, are BlindAsABat.

      • BlindAsABat

        Actually, I have an IQ of about 135, so while I may not be the brightest, I probably am brighter than you. Considering how many different trades employ welding and not everyone who is exposed has to be welding, it affects more folks than you expect. I didn’t even mention things like arc lighting, UV germicidal lights (as used in hospitals) or even florescent lights. So yeah, I’m BlindAsABat, but you’re a troll. Get back under your bridge.

    • But 2 year olds seldom do any welding whereas the concern is the screens are damaging children and adults. How many people are in welding profession and how many do it without protective eye wear? I think that was the point.

      • BlindAsABat

        How many have grown up with florescent lights, watching color TV (which has *blue* phosphors,) and yeah there is a limited number of welders, but the number of people exposed is greater than that. Have you ever been to a shipyard and seen how a single welder lights up an area larger than just the ship he is working on with blue light? This often at night due to ships being expensive and needing to be on their way ASAP. I’ve watched from across the bay and been amazed at the amount of light, and I’m an experienced welder myself. Blue light is **NOT** something new due to computers, smartphones, or tablets. These complaints in the article should have been showing up decades ago, not just recently. This is merely an article about FUD for click-bait. The facts weren’t even important enough to get correct, so I believe you may be one of the persons who have missed the point.

  4. Even as a designer, I’ve been wearing the yellow Gunnar lenses during the day in front of my 27″ iMac screen. Saves a lot of eyestrain. I just take them off when I’m making color decision, which isn’t all that much of the time.

    Now I’m thinking about wearing them in the evening when looking at iPad or other screens. In the evening on my Macs I run “Redscreen” which is like f.lux but I like it’s customizability more.

  5. I don’t understand how an app can block the blue light that’s being produced by the LED that lights the display. It makes sense that it can lower the amount of blue being viewed by removing the blue pixels from the display, but the LED itself is still emitting the blue spectrum while illuminating the screen. What am I missing?

  6. just thinking

    Gotta love how this “scientific literature” reaches vague conclusions described in terms like (may, could, is linked to, is considered, appears, can) based on mere correlation, observation in rodents and various optometrist reports. Unfortunately, for many of these biological sciences it is impossible at this time to properly control input data and properly measure output data to infer plausible statistical conclusions.

  7. I don’t want to jail break my iOS devices. I wish Apple would let users adjust color temp of iOS displays. Right now, I just turn it down to about 15% of full brightness (Apple default is 50% which is way to bright!)
    My older 27 inch iMac absolutely causes migraines. I have that turned all the way down. But the LEDs in it (the back lights are the LEDs) are just too much sometimes. I also set the color temp warmer (as a designer, I prefer the setting for print proofing, which is warmer) But it makes no difference.
    I have no issues with an older fluorescent back lit Apple monitor. A newer but very cheap LED I use on another Mac is somewhat better than the iMac.

  8. Bo3b Johnson

    Wow, does anything talking about health nowadays have to be written terrorism style? Be Afraid! Cancer! Cataracts! Diabetes! Seems like the kitchen sink for health risks.

    I also like that we throw in the sort of official sounding PubMed, with no actual links. Makes it sounds vaguely science related without all that pesky data to back it up.

    And from light? Seriously? Blue light?

    One teensy, inconvenient, fact: Outdoor sunlight: 32,000 Lux. Cell phone light: 200 Lux.

    But no, really, best to be ‘cautious’. But most importantly, afraid.

    • Outdoor light at day is not harmful and does what it’s supposed to do- wake us up. Nobody tells you to worry about the sun or, for that matter the light from devices, but only during the day. it’s the blue light at night that is harmful since it’s not natural to us; it sends false signals and messes up our circadian rhythm. We used to have only amber lights after sunset (think candles, campfires, even older lightbulbs) which induce sleepiness.

    • At northern latitudes, sunlight comes in at a shallow angle, so its bath through the atmosphere is longer. Blue light tends to be scattered, while red light penetrates. It’s like a perpetual sunset.

    • People do tend to stay up longer during the summer months in northern countries. The sun commonly gets “credit” for this – even if somewhat filtered at night due to the sun being low in the sky, it still carries enough blue light for it to be a potential factor.

    • After living in a northern country all my life I still find it difficult to sleep for more than a couple of hours during summer nights (and equally difficult to wake up properly in the winter). Completely opaque blinds in the summer (and light therapy in the winter) helps a bit though. I guess we should be adapted to the seasonal differences, but it doesn’t feel like it! Would be interesting to read some research on it.

  9. jane maple

    Would someone please teach Ms Moore the difference between heat as the word is used by the lay public, and colour temperature. She clearly doesn’t even know that there is a difference and a lot of the article is inaccurate as a result.

    • Carl Quinn

      The article is technically correct. Hotter colors of white are bluer, cooler colors are redder. The lay public uses an archaic non-physics based analogy of blue being cold like water and red being hot like fire.

      • No, higher colour temperature does NOT equal ‘hotter’ light. It is nonsense to talk about the heat of light unless you are talking about infra-red.

        The dangers discussed in this article, assuming they are real, are because of the eye and body’s response to specific wavelengths of light. The article makes it sound like the light is frying your eyes, when in fact it is triggering a chemical response that has nothing to do with heat.

        • normscleansingfire

          Infra-red feels ‘hot’ because our skin absorbs the energy from the particles of light.

          Blue light carries more energy per photon than infra-red light, because it has a higher frequency/shorter wavelength. This article uses ‘heat’ in a really simplistic way and should have been better written, but the general idea is that blue light causes more damage to tissues per photon than red light, which is just as true as the notion that UV light does more damage than blue, red, and infra-red light.

          However, the actual rate of transfer of energy is all about the number of photons, the rate at which they are hitting the lens (the intensity of the light). And the article fails to mention this at any point.

  10. I have to agree with this. I have noticed, that when I am away from most computer use, such as camping for any length of time, I can & do sleep well. When I am on the computer for hours, esp. at night, before I close my eyes, in a darken room, I see flashes of lights and a greyish fog. Also, I toss and turn and have headaches more. I would suggest that everyone should take a couple of weeks without any computers, TV, etc, and see if you see any difference. When I am camping, I am usually camping for 3 or more months due to my profession (archaeologist), so I am digging more and less on computer.

  11. Mike Thurgood

    There is no reason to argue against the fact that blue light over the wavelength range quoted in the article can harm the eye lenses. There would seem to be two ways to deal with this problem. First, incorporate a blue filter in the screens of all new television sets; and, second, have specs available with lenses which absorb the relevant blue wavelengths. The latter obviously to be used with the current generation of modern flat screen TVs. Spectacle lenses can be easily coated. For example, the lenses of my outdoor specs are coated with a UV absorbing layer.

  12. I work long computer hours with lots of writing and graphic work, and I also use the Flux app. And let me tell ya, it makes a big difference being able to wind down to sleep. I can’t tell you if I’m healthier from it or not, but there’s definitely something to the whole avoid blue light at night thing. And I think psychologically, it’s easier to disconnect. I do use daylight blubs (broad spectrum) when I do my fiber design work though. The colors and textures show up better under “close to true sunlight” conditions. But I avoid them in the evening.

    I also remember years ago watching a news interview with a doctor who said use red night-light bulbs if you just need one, because getting up in the middle of the night with a regular light will destroy your melatonin. I did that while my kids were babies waking up at all hours and it really helped me (and them) get right back to sleep.

  13. anything using ‘appears on Dr Oz’ regularly as a positive recommendation should be be put into the category ‘requires extra strong evidence’ given the history of woo on that show.

    • jim gallas

      You may be right. Actually, you don’t want to filter all of the blue light; you want to reduce it because blocking the blue light will distort the color of the display. And even better, you want to use a light filter that factors in the wavelength distribution of the light source (the LCD display), and the way the melatonin suppression occurs with the wavelength. The body’s own light filter, Ocular Lens Pigment, already does this – except you have to wait till you’re in your late twenties before it develops in your eyes.