2. The LEDs tested are not the "warm white" (1500-2500K) commonly used as replacements for incandescent bulbs in the US. They're the "blue white" (>4000K) ones, or pure blue or pure green at specific wavelengths.
With those constraints, it's an interesting result. It does not mean you need to run home and rip all the lights out, though.
Yeah. The hypothesis seems to be that the blue end of the spectrum is the danger here, LEDs being relatively bluer than incandescents or common fluorescent phosphors.
But even so, the high energy spectral content of indoor LED lighting is much, much less than what you see from direct sunlight. If LEDs are really a vision risk to the modern office worker, they're significantly less so than the same risk of agricultural or other outdoor workers.
One group of people who could potentially be affected: people who use anti-SAD lighting (especially people building souped-up DIY rigs: https://meaningness.com/metablog/sad-light-led-lux). Those use LEDs and are specifically meant to be very bright and very blue.
Hopefully this turns out not to be a big deal. Having to choose between depression and retina damage would sure suck :/
They got damage at 6000 lux with pretty much all the light sources. The interesting result is that they got significantly more damage with the white LED source than with other sources at 500 lux.
Someone else was nice enough to post a link to the paper:
For comparison, typical artificial light levels in an office are more like 300 lux. IES recommended illuminance for a professional indoor basketball court is 1000 lux.
Daylight ranges up to 120,000 lux, so 6000 is several times the lighting in most spaces, but still nowhere near bright sunlight.
That said, from the abstract (I don't have journal access), it sounds like they found a result in both 24H high intensity, and in on/off "domestic levels".
Is the 6000 lux you mentioned their value for high intensity, or is that what they considered as domestic levels?
Not to take away from your fundamental point, but to add information to anyone shopping for lighting:
4000K isn't "blue white" or even what's usually called "cool white". It's warmer (that is, more weighted toward the yellow-red end of the spectrum) than sunlight at midday (5000K-ish) and much warmer than LED and fluorescent sources that are noticeably blue (6000K+).
Beyond that, sources with a flatter or fuller spectrum (most commonly measured as color rendering index, or CRI) will have less of a blue peak even at cooler color temperatures.
And yes, 6000 lux is a lot of light. Staring at a 100W incandescent light bulb from 1 meter away will put about 100 lux on your eyes, by way of comparison.
> The data suggest that the blue component
of the white-LED may cause retinal toxicity at occupational
domestic illuminance and not only in extreme
experimental conditions, as previously reported.
The domestic illuminance they used was only 500 lux, which they describe as the "domestic classic light intensity".
Can't see the full paper, just the abstract, but another thing I wondered if they took into account is the effect of strobing. They didn't include a control that doesn't strobe (such as halogen), since CFLs strobe in the kHz range. LEDs may or may not strobe depending on how they are driven and that isn't stated in the abstract.
It does however, seem much more likely that this is to do with extra energy in the UV end of the spectrum, which IIRC WW LEDs cut a lot more of (as well as the additional, visible blue light that makes CW seem so much brighter).
6000 lux of BLUE light is a _ton_ of photons. The light meter they used applies the human sensitivity curves to the photo frequencies. The sensitivity of the human retina to blue light is very very poor. Most of the time you see graphs of sensitivity vs wavelength the curves have been normalized. Here is one graph where the blue channel has only been inflated by 10x: http://www-i6.informatik.rwth-aachen.de/web/Misc/Coding/365/...
So 6000 lux of blue is approximately 30x as many green photons. For blue LED plus yellow phosphor that 30x "yellow" will be the signal that you will use to decide "that's enough light to perform work."
The rat's eyes were definitely cooked by all of the blue. Imagine if they had used near UV or near infrared LEDs and the same meter to calibrate the intensity. Cooked rats.
Although if you want to measure an effect in a reasonable time frame, you'd up the concentration. You won't measure much damage from a "reasonable" amount of lead in a short time frame, either, but over longer time scales you'll probably conclude that you want to rescale reasonable downwards.
I don't have access behind the paywall, but I do run engineering for a luminaire manufacturer. Do you have access to the full details of the illuminance source and output?
Wow, guess you can get LED poisoning :-). The question that I've heard being bandied about is that people use brighter (higher luminous flux) LED lights and displays for better visibility and the question was whether or not the pupil dilation reflex was appropriately triggered (sort of like going blind by looking directly at a total eclipse of the Sun). If a cause could be identified and reproduced it seems the "fix" would be simply adjusting the spectrum of the output to clue your eye into the fact that it was really bright.
Anyway, I wonder if these guys got a follow up grant, does anyone know?
I'm curious why LEDs used in light bulbs could cause eye damage, but not for backlights in computer monitors or other common uses? I kindof get the impression that the blue-tinted led's are being considered 'evil' and studies are 'showing' that they are 'harmful'. Certainly these blue led's have far far far less of any wavelength at all of output than say the sun at noon...
I wouldn't be surprised to see that this study is never reproduced.
Having now skimmed through the paper, there's one very reassuring thing that no-one's pointed out yet:
Long-term exposure to LED at 500 lux, in cyclic
(light/dark) conditions induced retinal damage only in albino rats but not in pigmented rats
So, at household levels WITHOUT artificially dilated eyes, only the albino rats (who one would assume are more sensitive to light) suffered any damage.
Given that, as another commenter mentions, rats are likely to be more sensitive to light than humans anyway, this looks like it's a reassuring rather than concerning result. Just don't artificially dilate your eyes then stare at a super-bright LED bank for 24 hours!
One area where this can matter more than standard lighting is light therapy devices. I have a circadian sleep disorder and for those light therapy is one of the few medically recommended treatments (it is also recommended in the winter for seasonal affective disorder). There are two basic types of light therapy devices, a bright light that you set on the table nearby and a less bright light in a visor that you put near your eyes. I think LEDs are universal in the visor style ones and quite common in the table ones. The blue spectrum is more effective than other wavelengths so they are frequently focused on the blue spectrum although some of the table ones are white light. They are only supposed to be used for a half hour or hour at most.
I just tried for a couple of weeks a visor style light that is just over 500 lux at 500nm dominant wavelength (blue-green; it looks green and is a longer wavelength than most such devices). While it didn't seem super bright, it did seem fairly bright and actually caused me mild pain, similar to what bright light occasionally causes. The lower 315 lux level did the same at first. I started with that a few days and it seemed like my eyes adapted quite a bit so I moved to the higher level. I got spooked after noticing the pain later in the day one day after using the visor on high in the morning, so I haven't tried the lower level again to see if that still causes pain. The manufacturer said that in studies about 3% of people report that problem.
Anyway, it seems to me that my use of the visor might be similar to the lighting in this study. I haven't noticed this issue with other artificial lighting, although I haven't been around LEDs that much that I know of, mostly compact flourescents. The closest is a led light alarm clock that I have stared at at close range for a while and is listed at 300 lux, although I'm not sure if that is what I am getting even a few inches away. The visor light does have a 50-166 hz pulse so that could be related; I'm not sure about the light alarm, but I never noticed that flicker the way the visor does.
Anway, 500 lux at eye level at least can be quite a bit different than normal lighting.
I don't like the light given off by LEDs. It looks unreal/surreal to me, and makes me uneasy if it's the only light source. Especially the blueish ones. Before installing them I was very enthusiastic about all the benefits of low power lighting, but now I want to switch back to halogen bulbs, or at least very warmly colored LEDs.
I'm oversensitive though. E.g. slightly flickering energy saving lamps make me dizzy, exacerbated by ACs making my eyes dry (hello, Ikea).
I hope those nano-coated regular light bulbs will become a thing.
> using different LEDs (Cold-white, blue and green)
I wonder what the results would look like for warm LEDs ~ 2700K. I used to be a Cold-white aficionado but moved to warms for everything. If I experiment by suddenly switching between my cold and warm lights its pretty jarring (warm seems more relaxing).
I think it's important to recognize that this is far from the only study pointing to this, and that similar problems are associated with CFL's.
For example, here is a 2014 study, "White Light–Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model" http://ehp.niehs.nih.gov/1307294/
Links to eye toxicity, macular degeneration, and blindness are not the only problems associated with new lighting either, which tends to be very heavy in the blue components. Lots of research links usage of blue-heavy white lighting to damaging circadian rhythms, which can lead to significant health effects. https://www.sciencedaily.com/releases/2011/09/110912092554.h...
Does anyone else use something like flux or redshift permanently? These programs change the color temperature of your monitor based on the time of day, but I use them all day.
Otherwise my eyes start watering after awhile and get itchy and irritated. I think I must be sensitive to blue light. I used to set it around 4500 color temperature but now I lowered it to 4000.
I use f.lux on a rather high setting 24/7 at work, most of the day at home (where I have better lighting), and at night on my phone. Using it all day at work with the 20/20/20* rule has greatly reduced my eye stress.
* I made a simple website using the Notifications API which reminds you every 20 minutes to take an eye break.
I use it for the majority of the day (especially now, in the winter, where the day is just a few hours long).
> I think I must be sensitive to blue light.
My eyes hurt after a few minutes of looking at my girlfriend's iPad/computer screen. She's the opposite and thinks my screen is constantly stained yellow.
If blue light exposure causes Macular Degeneration I wouldn't be suprised if environmental and genetic effects would cause some people to be affected by it and others not.
This is the case for noise related hearing loss. Everybody loses hearing acuity a bit as they get older, but exposure to noise accelerates this process. Exposure to ambient sounds in the high 60s (decibels) is harmful to a small segment of the population. That's not very loud, but fortunately most people are not hurt at that level. Occupational exposure levels are set considerably above that point.
Just a word of caution not to draw precipitated conclusions since this is a study in preclinical phase tested on rats. Of course it means something and requires further study but just wanted to emphasise the fact that it wasn't applied on humans.
Two more situations where this spectrum and intensity is in use: on stages (music,TV) the old PAR lights are nowadays nearly fully replaced by strong led spots shining directly on the actors. Still you don't spend 22h on stage of course.
The other situation would be artificial gardening system where a heavy bended light spectrum is used to grow lettuce etc.
Oh great, no doubt this will picked up as a sensationalist news item that'll inevitable lead to a futile debate with my elderly inlaws about how dangerous LED lights are, because this is proof, no matter how much my inlaws are NOT nocturnal albino lab rats.
How does this relate to staring at OLED at LED screens? Are they potentially dangerous as well? Could you prevent harm by running a tool like F.lux and lower the brightness?
Everything is potentially dangerous. The article reported an experiment done on albino rats; that's not much indication of a serious risk to people; it only means that someone should look into it further.
Color temp = 5000K. Output is 13000 lumens. The sales page assumes 10 ft x 15 ft illuminated area (install height not specified but probably 8 ft) = 250 ft^2 or ~23 m^2.
Doing the math yields 565 lumens / m^2. Should be a little more at standing (eyes ~5ft off the floor) height.
[+] [-] hprotagonist|9 years ago|reply
1. 6000 lux is a _lot_ of light.
2. The LEDs tested are not the "warm white" (1500-2500K) commonly used as replacements for incandescent bulbs in the US. They're the "blue white" (>4000K) ones, or pure blue or pure green at specific wavelengths.
With those constraints, it's an interesting result. It does not mean you need to run home and rip all the lights out, though.
[+] [-] ajross|9 years ago|reply
But even so, the high energy spectral content of indoor LED lighting is much, much less than what you see from direct sunlight. If LEDs are really a vision risk to the modern office worker, they're significantly less so than the same risk of agricultural or other outdoor workers.
[+] [-] Analemma_|9 years ago|reply
Hopefully this turns out not to be a big deal. Having to choose between depression and retina damage would sure suck :/
[+] [-] upofadown|9 years ago|reply
Someone else was nice enough to post a link to the paper:
* http://www.sciencedirect.com.sci-hub.ac/science/article/pii/...
[+] [-] wlesieutre|9 years ago|reply
Daylight ranges up to 120,000 lux, so 6000 is several times the lighting in most spaces, but still nowhere near bright sunlight.
That said, from the abstract (I don't have journal access), it sounds like they found a result in both 24H high intensity, and in on/off "domestic levels".
Is the 6000 lux you mentioned their value for high intensity, or is that what they considered as domestic levels?
[+] [-] Zak|9 years ago|reply
4000K isn't "blue white" or even what's usually called "cool white". It's warmer (that is, more weighted toward the yellow-red end of the spectrum) than sunlight at midday (5000K-ish) and much warmer than LED and fluorescent sources that are noticeably blue (6000K+).
Beyond that, sources with a flatter or fuller spectrum (most commonly measured as color rendering index, or CRI) will have less of a blue peak even at cooler color temperatures.
And yes, 6000 lux is a lot of light. Staring at a 100W incandescent light bulb from 1 meter away will put about 100 lux on your eyes, by way of comparison.
[+] [-] y7|9 years ago|reply
> The data suggest that the blue component of the white-LED may cause retinal toxicity at occupational domestic illuminance and not only in extreme experimental conditions, as previously reported.
The domestic illuminance they used was only 500 lux, which they describe as the "domestic classic light intensity".
[+] [-] robert_tweed|9 years ago|reply
It does however, seem much more likely that this is to do with extra energy in the UV end of the spectrum, which IIRC WW LEDs cut a lot more of (as well as the additional, visible blue light that makes CW seem so much brighter).
[+] [-] simonster|9 years ago|reply
[+] [-] drjasonharrison|9 years ago|reply
So 6000 lux of blue is approximately 30x as many green photons. For blue LED plus yellow phosphor that 30x "yellow" will be the signal that you will use to decide "that's enough light to perform work."
The rat's eyes were definitely cooked by all of the blue. Imagine if they had used near UV or near infrared LEDs and the same meter to calibrate the intensity. Cooked rats.
[+] [-] tedunangst|9 years ago|reply
[+] [-] hackuser|9 years ago|reply
From the article:
we investigate, in albinos and pigmented rats, the effects of different exposure protocols
It's much too soon to rip out the lights in any event.
[+] [-] phasetransition|9 years ago|reply
[+] [-] thro1237|9 years ago|reply
[+] [-] marze|9 years ago|reply
[+] [-] stuckagain|9 years ago|reply
[+] [-] unknown|9 years ago|reply
[deleted]
[+] [-] profalseidol|9 years ago|reply
[+] [-] ChuckMcM|9 years ago|reply
Anyway, I wonder if these guys got a follow up grant, does anyone know?
[+] [-] justin_vanw|9 years ago|reply
I wouldn't be surprised to see that this study is never reproduced.
[+] [-] thenomad|9 years ago|reply
Long-term exposure to LED at 500 lux, in cyclic (light/dark) conditions induced retinal damage only in albino rats but not in pigmented rats
So, at household levels WITHOUT artificially dilated eyes, only the albino rats (who one would assume are more sensitive to light) suffered any damage.
Given that, as another commenter mentions, rats are likely to be more sensitive to light than humans anyway, this looks like it's a reassuring rather than concerning result. Just don't artificially dilate your eyes then stare at a super-bright LED bank for 24 hours!
[+] [-] joveian|9 years ago|reply
I just tried for a couple of weeks a visor style light that is just over 500 lux at 500nm dominant wavelength (blue-green; it looks green and is a longer wavelength than most such devices). While it didn't seem super bright, it did seem fairly bright and actually caused me mild pain, similar to what bright light occasionally causes. The lower 315 lux level did the same at first. I started with that a few days and it seemed like my eyes adapted quite a bit so I moved to the higher level. I got spooked after noticing the pain later in the day one day after using the visor on high in the morning, so I haven't tried the lower level again to see if that still causes pain. The manufacturer said that in studies about 3% of people report that problem.
Anyway, it seems to me that my use of the visor might be similar to the lighting in this study. I haven't noticed this issue with other artificial lighting, although I haven't been around LEDs that much that I know of, mostly compact flourescents. The closest is a led light alarm clock that I have stared at at close range for a while and is listed at 300 lux, although I'm not sure if that is what I am getting even a few inches away. The visor light does have a 50-166 hz pulse so that could be related; I'm not sure about the light alarm, but I never noticed that flicker the way the visor does.
Anway, 500 lux at eye level at least can be quite a bit different than normal lighting.
[+] [-] lostdog|9 years ago|reply
[+] [-] manmal|9 years ago|reply
I'm oversensitive though. E.g. slightly flickering energy saving lamps make me dizzy, exacerbated by ACs making my eyes dry (hello, Ikea).
I hope those nano-coated regular light bulbs will become a thing.
[+] [-] Torkel|9 years ago|reply
(Sorry if this is a dupe and hope this link is persistent, I scanned the thread and saw some people lacking access and didn't see any sci-hub post)
[+] [-] clumsysmurf|9 years ago|reply
I wonder what the results would look like for warm LEDs ~ 2700K. I used to be a Cold-white aficionado but moved to warms for everything. If I experiment by suddenly switching between my cold and warm lights its pretty jarring (warm seems more relaxing).
[+] [-] mtw|9 years ago|reply
[+] [-] adrr|9 years ago|reply
[+] [-] threepipeproblm|9 years ago|reply
For example, here is a 2014 study, "White Light–Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model" http://ehp.niehs.nih.gov/1307294/
This article cites numerous studies in the quotes section ( scroll down) http://lowvision.preventblindness.org/daily-living-2/artific...
Links to eye toxicity, macular degeneration, and blindness are not the only problems associated with new lighting either, which tends to be very heavy in the blue components. Lots of research links usage of blue-heavy white lighting to damaging circadian rhythms, which can lead to significant health effects. https://www.sciencedaily.com/releases/2011/09/110912092554.h...
This year the AMA issued a public safety warning regarding LED street lights because of the association with circardian rhythm disruption and related health effects. http://www.cnn.com/2016/06/21/health/led-streetlights-ama/in...
Paul Jaminet has stated that circadian rhythm disruption has been more strongly linked to cancer than any food study, ever.
I use the GE Align PM LED bulbs, available on Amazon, which cut out most of the blue frequencies and largely address both sets of problems. Highly recommended. https://www.amazon.com/GE-Lighting-93842-350-Lumen-Dimmable/...
EDITED to correct summary of AMA announcement.
[+] [-] chubot|9 years ago|reply
Otherwise my eyes start watering after awhile and get itchy and irritated. I think I must be sensitive to blue light. I used to set it around 4500 color temperature but now I lowered it to 4000.
[+] [-] vdnkh|9 years ago|reply
* I made a simple website using the Notifications API which reminds you every 20 minutes to take an eye break.
https://johnbartos.github.io/eyebreak/
[+] [-] akeck|9 years ago|reply
[+] [-] sndean|9 years ago|reply
> I think I must be sensitive to blue light.
My eyes hurt after a few minutes of looking at my girlfriend's iPad/computer screen. She's the opposite and thinks my screen is constantly stained yellow.
[+] [-] m3ta|9 years ago|reply
[+] [-] PaulHoule|9 years ago|reply
This is the case for noise related hearing loss. Everybody loses hearing acuity a bit as they get older, but exposure to noise accelerates this process. Exposure to ambient sounds in the high 60s (decibels) is harmful to a small segment of the population. That's not very loud, but fortunately most people are not hurt at that level. Occupational exposure levels are set considerably above that point.
[+] [-] joaomagalhaes|9 years ago|reply
[+] [-] theseadroid|9 years ago|reply
https://www.researchgate.net/profile/Eva_Chamorro/publicatio...
[+] [-] AhtiK|9 years ago|reply
I have this exact same model and it has been working great, too bad if carrying a significant risk.
[+] [-] moritzsimon|9 years ago|reply
The other situation would be artificial gardening system where a heavy bended light spectrum is used to grow lettuce etc.
[+] [-] jp555|9 years ago|reply
Sigh...
[+] [-] LeifCarrotson|9 years ago|reply
[deleted]
[+] [-] Little_John|9 years ago|reply
This pulse laser was so powerful that at discharge through the microscope it could create a white spark in mid-air; the
so-called waist area.
I Hired on to CooperVision as a Developmental Tech, I inadvertantly grounded a flash-circuit while the laser exit face
aligned to my eyes.
The Fluke Meter actually bounced a centimeter into the air at discharge, and I saw a moderate orange glow for a bare
instant.
Immediately after, and today, when I gaze into a clear blue sky, I see a "small dounut shadow" of two to three degrees
in my mid to lower right field.
The contrast of the Donut image has decreased over the years but decades later, I see it. What do you Know? I got shot with a surgical welder.
-No worries though, No worries at all.
[+] [-] fsiefken|9 years ago|reply
[+] [-] hackuser|9 years ago|reply
[+] [-] squozzer|9 years ago|reply
https://www.haikuhome.com/garage-light
Color temp = 5000K. Output is 13000 lumens. The sales page assumes 10 ft x 15 ft illuminated area (install height not specified but probably 8 ft) = 250 ft^2 or ~23 m^2.
Doing the math yields 565 lumens / m^2. Should be a little more at standing (eyes ~5ft off the floor) height.
[+] [-] BHSPitMonkey|9 years ago|reply