
LEDs may cause retinal toxicity at occupational domestic illuminance - vmarsy
https://www.ncbi.nlm.nih.gov/labs/articles/27751961/
======
hprotagonist
Some immediate thoughts:

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.

~~~
Analemma_
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](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 :/

~~~
GenerocUsername
Also, those lights are suggested for skin exposure, not for staring directly
into or for illuminating your space... still though, proximity would encourage
more harmful interactions.

~~~
mordechai9000
They are not intended strictly for skin exposure. They are marketed and used
as a way to expose your eye (brain) to the high light levels that (may be)
needed to regulate diurnal activity.

~~~
jsjohnst
The Phillips light specifically has warnings about not looking directly at it,
but rather having it in your peripheral vision. It calls out that eye damage
can happen if staring directly at the light for prolonged periods.

~~~
null000
The lights that I've looked at (look up liberty vt20 for example) have all
suggested that eye contact with the light, peripheral or otherwise, is
essential for results.

------
ChuckMcM
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?

------
justin_vanw
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.

~~~
whatshisface
Turn the lights off in a room, and see how much of it your monitors can
illuminate. Our eye's logarithmic response to light can end up confusing us
about the mile-wide canyon between a glow and a light.

~~~
ogrisel
Sure but at the same time we are not staring directly at light bulbs for 8
hours a day.

~~~
thefalcon
Sure but a mile-wide canyon is a mile-wide canyon. They're just not in the
same ballpark.

------
thenomad
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!

~~~
barinvon
"Just don't artificially dilate your eyes then stare at a super-bright LED
bank for 24 hours!"

Looks like my weekend plans are shot

------
joveian
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.

~~~
lostdog
Is the light therapy having an effect on your circadian rhythms?

~~~
joveian
The visor did actually seem to help more than any other bright light in the
morning method I've tried (including getting natural light in the morning). So
I wish it didn't hurt my eyes :(.

------
manmal
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.

~~~
incongruity
I'd recommend you look for high-CRI LED bulbs – I've had similar reactions to
yours but I'm satisfied with some of the better/higher CRI bulbs(color
rendering index
[https://en.wikipedia.org/wiki/Color_rendering_index](https://en.wikipedia.org/wiki/Color_rendering_index)).
They tend to be harder to find, but they're out there. GE Reveal bulbs are
higher CRI, for example and I've found other brands through some specialty LED
dealers that almost match halogen bulbs.

~~~
amluto
Be careful, though. Soraa, for example, makes fancy LEDs with CRI 95, and they
use violet LEDs behind the phosphor. The problem is that the phosphor lets a
decent fraction of the source light through. Soraa even has a nice graph on
their spec sheet, and it has a violet peak.

Also, a neat fact: _all_ CEC qualified LEDs are high CRI.

(P.S. I bought a GE Reveal once and it had the worst color fidelity I've ever
seen. Some normally bluish surfaces were distinctly green. I don't understand
how it has a high CRI.)

~~~
lightedman
GE has been busted by myself falsely advertising their UV LED bulbs. In fact,
I'm currently looking for more people that bought these A19-style UV Black
Light bulbs from GE so we can start a class-action suit for false advertising
and unfair competition.

In short, I wouldn't trust GE for LEDs. In fact, I'm so disillusioned with
almost every company out there (Cree, Philips, GE, Sylvania) that I've simply
gone back to building my own lights for my specific purposes. I can't trust
any of these companies to be accurate or truthful in their marketing.

~~~
j_koreth
> that I've simply gone back to building my own lights for my specific
> purposes.

Is this what your username references?

~~~
lightedman
Yup. I design my own LED units, have a company called SinkPAD (I think it's
Adura, now) make the boards, then I populate the boards myself.

~~~
Zak
Maybe you could point me in the right direction. I'm looking to construct a
panel that can make it look like day, but has infinite dimming.

Making daylight is easy enough. The Nichia 219B LED in 5000K R9050 (CRI 90+,
R9 50+) is beautiful. 12-18 of them will comfortably make over 5000 lumens
without having to be driven especially hard. It's not terribly hard to come up
with options to wire them up and heatsink them properly either.

What I haven't been able to find is a suitable power supply and driver. I want
to plug it in to 100-240V and have a dimmer knob giving me 5-5000+ lumens via
current regulation, not PWM, though very fast (> 10kHz) PWM might be
acceptable. Yes, I'm aware the tint will shift a bit through the brightness
range without PWM. I'm OK with that.

~~~
lightedman
"I'm looking to construct a panel that can make it look like day, but has
infinite dimming."

Infinite? Not happening, but if you want to get CLOSE, your best bet is in a
simple benchtop voltage and current regulator. I use four Nichia 219B LEDs to
light my 55-gallon aquarium, are you SURE you really need 5,000 lumens? You
could probably get away with just four of those, a fixed 12V power supply with
adjustable current, and be done with it, they're ungodly bright and a quad of
those can match up with the Cree MK-R.

~~~
Zak
It need not be truly infinite or stepless as long as it has hundreds of steps.
I want to dial in the ideal level, rather than pick from say... 10 options.

I'm sure I want over 5000 lumens. When I want my room well-lit to promote a
sense of alertness and compensate for shorter days in winter, my best current
option is a flashlight that produces about 4200 lumens bounced off the
ceiling. No, that's not one of those BS marketing numbers: the light is a
Jetbeam T6, which in stock form uses four Cree XP-Ls powered from four 18650
Li-ion batteries. Independent tests, including my own have found its claimed
performance to be accurate. I swapped the XP-Ls for Nichia 219Cs (5000K, CRI
80+, R9 unspecified) and measured about a 2% loss of output, but increased
intensity. This works as a room light, but requires an external cooling fan to
run on high for longer than about 10 minutes (it has a thermal sensor and
stepdown), and the batteries can only keep up with that output for a bit over
an hour. 219Cs are more efficient than 219Bs and can be driven much harder,
but aren't as pretty. Even the recently-released R9050 (CRI: 90+, R9: 50+)
version just doesn't look as nice to me.

Four 219Bs definitely can't produce 5000 lumens. The 90+ CRI versions peak at
about 600[0], but I don't want to run them at peak output; the harder they're
driven, the stronger the spectral peak of the underlying blue LED. I want to
run them at about 300lm/ea. 12 of them will get me that, but I'd actually
rather have more than 5000 lumens.

Thanks for responding. I was hoping for an off the shelf driver, but it looks
like I'm going to be improvising a bit more.

[0]
[http://budgetlightforum.com/node/27652](http://budgetlightforum.com/node/27652)

~~~
lightedman
Here's an idea. Get a single 50w COB LED that can match or get close to the
Nichia (they exist, I'm sure of it.) Actually, Nichia has some of their own
that do match -
[http://www.nichia.co.jp/en/product/led_product_data.html?typ...](http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVEWJ048Z%27)
and
[http://www.nichia.co.jp/en/product/led_product_data.html?typ...](http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVELJ048Z%27).
Then you just need a simple heat sink, and fixed voltage power supply with
adjustable current. Those aren't too expensive, but you're still looking at
roughly ~$80 in total BOM.

~~~
Zak
I thought about getting one of those bigger arrays, but I'm concerned that the
light they produce may not be as pretty as the 219B even if they have the same
color temperature and CRI on paper. The 219C, for example is not, though it's
still very nice and capable of quite a bit more output. Output per emitter and
overall efficiency aren't major concerns for me: we're talking about around
90W for 6300lm driving 18 219Bs at 1500mA each.

It's also difficult to find the 048Z available in single quantities. I didn't
find the R9050 version on Octopart, Other versions cost $50-60, while 219Bs in
several tints are readily available from suppliers of DIY flashlight parts for
$3/pc. Getting 219Bs and triple or quad copper MCPCBs is easy, and they can be
configured for any multiple of about 3 volts, while the 048Z requires a 50
volt power supply.

I was expecting to spend over $100 when all is said and done.

~~~
lightedman
"It's also difficult to find the 048Z available in single quantities"

Just ask Nichia for an engineering sample. :) Boom, free sample if they've got
one for you to utilize. I don't know how many Cree, KingBright, Nichia, Osram,
and Epistar LEDs I've got just because I ask to test them.

As for the 50V power supply, it'll run on a 48V 1.25A driver. You'll be fine
and those are about $20 each.

~~~
Zak
I have hundreds of dollars worth of flashlights I got by offering to write
reviews, but asking for an engineering sample never crossed my mind. I may
have to try that.

~~~
lightedman
If you point out to them reviews you've written (some of them mentioning their
LEDs favorably) you'll get the engineering sample no problem, I imagine. They
like people that promote their products and bend over backwards to get them
tiny things that cost them far less than what they're going to get in
potential advertising.

------
Torkel
Link to full paper via sci-hub: [http://twin.sci-
hub.cc/ac1a63745360991b7b9a42390ab3faa8/krig...](http://twin.sci-
hub.cc/ac1a63745360991b7b9a42390ab3faa8/krigel2016.pdf)

(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
> 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).

------
mtw
In a study done on rats... evidence is low, i would wait for large scale
studies before concluding on LED health effects

~~~
adrr
Aren't rats nocturnal? Seems like a very poor study.

~~~
sfrailsdev
Lab rats are brown rats, which aren't nocturnal, but active day and night. I'm
not sure that's important for a test of damage to the eye, but there you go.

~~~
Raphmedia
Their vision is still really different to that of humans.

~~~
grzm
Sounds like you have some background on this. Would you elaborate? In
particular, how the differences make the research unlikely to be meaningful
with respect to humans?

~~~
Raphmedia
I have no background in eyes but I have on rats. I can't affirm that the
differences would make that study invalid.

I can however tell you a few facts about rat eyes.

\- Their eyes are sensitive to ultraviolet.

\- They have a dichromatic vision, two sets of cones instead of three. (some
short wavelengths of ultraviolet/blue and a lot of greens)

\- They cannot reshape their lenses.

\- They have a lot more photo-receptors on their retina than us.

\- They are something between farsighted and nearsighted.

\- Poor binocular vision but big field of view.

Albino rats have more differences but I doubt they would have used any of
those in a study on eyes.

Rats do get the same kind of eyes disease humans do (cataracts, etc.) however
their sensitivity to light is really different. I don't think that it is ideal
to use such different eyes to test LEDs sensitivity.

------
threepipeproblm
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/](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...](http://lowvision.preventblindness.org/daily-
living-2/artificial-lighting-and-the-blue-light-hazard/)

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...](https://www.sciencedaily.com/releases/2011/09/110912092554.htm)

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...](http://www.cnn.com/2016/06/21/health/led-streetlights-
ama/index.html)

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/...](https://www.amazon.com/GE-Lighting-93842-350-Lumen-
Dimmable/dp/B00PLR3M0M/ref=cm_cr_pr_product_top?ie=UTF8)

EDITED to correct summary of AMA announcement.

------
chubot
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.

~~~
vdnkh
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.

[https://johnbartos.github.io/eyebreak/](https://johnbartos.github.io/eyebreak/)

~~~
mVChr
Workrave[1] is good for this too. Just set short breaks to 20sec every 20min.

[1] [http://www.workrave.org/](http://www.workrave.org/)

------
PaulHoule
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.

------
joaomagalhaes
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.

------
theseadroid
A related study on human retinal pigment epithelial cells

[https://www.researchgate.net/profile/Eva_Chamorro/publicatio...](https://www.researchgate.net/profile/Eva_Chamorro/publication/230878318_Effects_of_Light-
emitting_Diode_Radiations_on_Human_Retinal_Pigment_Epithelial_Cells_In_Vitro/links/0a85e535162107674c000000.pdf)

------
AhtiK
So the blue SAD lamps like this would be especially dangerous.
[https://www.amazon.co.uk/Klarstein-Therapy-Generous-
Display-...](https://www.amazon.co.uk/Klarstein-Therapy-Generous-Display-
Application/dp/B00PLSWOVO)

I have this exact same model and it has been working great, too bad if
carrying a significant risk.

------
moritzsimon
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.

------
jp555
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.

Sigh...

------
Little_John
It was a Q-Switched, Xenon pumped, Neodymium Garnet laser intended for Photo-
retinal Welding.

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
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?

~~~
hackuser
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.

------
squozzer
Thanks HN and NIH. Just in time too -- I have been mulling the purchase of an
LED garage light.

[https://www.haikuhome.com/garage-light](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
It sounds like you wouldn't be anywhere near the lux levels that present a
danger based on this post.

~~~
hackuser
Especially since the GP's author probably is not an albino rat (though I don't
want to presume).

------
rsi_oww
Should I worry that I've been using this daily for a year, per my sleep
doctor, for delayed sleep phase syndrome?

Philips GoLITE BLU - [https://www.amazon.com/Philips-GoLITE-BLU-Energy-
Light/dp/B0...](https://www.amazon.com/Philips-GoLITE-BLU-Energy-
Light/dp/B00M3SGCUE/)

30 minutes a day at the highest setting...

------
monochromatic
Is it possible that this is just a problem with LEDs that flicker[1] because
they don't rectify the AC? The blurb didn't mention this problem, but
presumably that's not what's going on here.

[1][https://www.youtube.com/watch?v=zcbk4H2iGYU](https://www.youtube.com/watch?v=zcbk4H2iGYU)

~~~
m-p-3
Now I'm wondering if my dog see my LEDs as a stroboscope.. :/

------
edwhitesell
Normally, I would not have thought much about this kind of an article. But, I
happen to be wandering around CES today and there was a booth somewhere that
was promoting some glasses to protect your eyes from LED lights.

If I happen across that booth again, I'll stop and look.

------
dbg31415
Car headlights seem to have gotten much brighter in recent years. I know this
is about domestic lighting, but... any concerns about car headlights and
streetlights? Those tend to be much much brighter than indoor LEDs.

------
zkhalique
Whew, I thought it said "LCDs". Are those safe?

------
wonko1
Reminds me of recent results using 40Hz blinking LEDs to treat Alzheimer's:

[http://news.mit.edu/2016/visual-stimulation-treatment-
alzhei...](http://news.mit.edu/2016/visual-stimulation-treatment-
alzheimer-1207)

I often fall into the trap of thinking that light at normally encountered
levels has essentially no effect. That's obviously not the case though.

------
gumby
Looking through the literature it looks like it might be Dry AMD (macular
degeneration) which is bad because it's currently untreatable. Wet AMD has
some treatments available.

------
adamwong246
raise your hand if this article prompted you to lower the color temperature of
your monitor via f.lux

------
simonhughes22
What implications does this have for VR glasses like the Vive and the rift.
Those use OLED displays?

------
xwowsersx
Can someone please tl;dr this? I seriously couldn't make it through the
abstract.

------
smaili
Does anyone know if this applies to organic LEDs as well?

------
EJTH
I always knew blue LEDs was bad for you. But its nice to have confirmation of
this.

Blue LEDs can seem almost blinding.

------
redsummer
When new phones or displays come out, the manufacturer will invariably brag
about the increased color gamut. Before I get blinded with science, it's time
to adjust my f.lux and night shift settings.

------
a_gopher
Using a yellow whiteboard marker, simply colour in the LED's face. Problem
solved.

------
cm2187
Name me a thing, a biscuit, a light bulb, a gadget, a piece of metal, where
there isn't some sort of agency that claimed that it increases the risk of
cancer by 0.3% based on a study based on a sample of 8 patients and an opinion
from the author's grandma!

