# LED = Eye Damage?



## WadeF (Jul 9, 2007)

I was recently talking about the benefits of LED's on a public forum and someone came along and said they will never use LED's because they cause eye damage. I know looking into the emitter isn't the best thing to do, but how dangerous are they? This person was concerned with LED's for home lighting, car head lights, etc. I guess situations where you'd be looking at the light source. 

I couldn't find any articles to back this up, other than blue and green LED's being bad, but I'm talking about white LED's. 

If anyone has any facts I'd be interested to hear them so I could pass them along. I tried a search, but I only came up with UV LED eye damage, which is pretty obvious.


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## LukeA (Jul 9, 2007)

'Someone' is a wacko, IMO.


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## Daniel_sk (Jul 9, 2007)

Damn, just today I was looking into the L1D CE beam .


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## fluke (Jul 9, 2007)

Who said that ?????:nana::nana::nana::nana:


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## tussery (Jul 9, 2007)

Funny because I would assume that LED's don't create much light in the color spectrums that would damage eyes.

Unless they are UV LED's.


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## jtr1962 (Jul 9, 2007)

Any intense light source can cause eye damage if stare at it for hours on end, including the sun or incandescent lamps. Maybe this person works for GE, so they have a vested interest in scaring people away from LEDs? Usually those who benefit from the status quo will think up all sorts of scare tactics to discredit anything new. Look at the number the automakers and big oil did with electric cars, for example. Or the fear about microwaves in the 1970s. Fact is some people just hate change, so when something new comes along, those with a lot of free time on their hands will start the gloom and doom scenarios. Best to just not pay them any attention. I love LEDs. Next time I'm up for a fixture change in maybe ten years it'll all go LED. The chandeliers will go LED as soon as viable LED replacements come out (within 3 years I'd say). I'm not worried about eye damage. If anything, LEDs are safer than either incandescents or fluorescents because they don't emit at all in the most harmful UV bands.


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## BB (Jul 9, 2007)

This might have come from a decade or so ago when LED's were equated with Laser Diodes wrt poorly worded European safety regulations...

I forget how it was worded--but I had to go around in circles with the regulatory engineer saying that little 5 milliamp Red/Green/Yellow indicator LED's were not going to damage anyone's eyes.

-Bill


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## ja10 (Jul 9, 2007)

I've heard people say that too, but like other people have said, staring at _any_ bright light source can hurt the eyes.

You know, sticking your hand in an open flame can cause burns too. That doesn't mean we avoid using candles or gas stoves, it just means we avoid holding body parts over open flames! Same with staring at LEDs.


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## IsaacHayes (Jul 9, 2007)

If you were to stare at the bare emitter up close of a high powered LED I can see it damaging your eyes. Same as looking at a bright powerful incandescent filament too. If you are seeing spots after briefly looking at something, then common sense tells you not to stare at it... But who stares at say their 100watt house hold bulbs? Or at a 500watt halogen floor lamp bulb? I doubt LED's would be an issue there...


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## dano (Jul 9, 2007)

All the LED based Streamlight models have a warning sticker that says the LED's radiation level may cause eye damage...

Couldn't comment on the specifics, though.


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## koala (Jul 9, 2007)

He can avoid buying LCD screens in the future. Apple laptops are fitted with LEDs backlight, many other manufacturers are coming up with LEDs too.


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## Manzerick (Jul 9, 2007)

if you could go blind from it... we'd have a whole lotta them aorund here!!!


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## geepondy (Jul 9, 2007)

I have had a Fluorescein angiogram performed in which pictures are taken of the back of your retina thru a lens. The flash was so bright that my vision afterwards was a red haze much like being in a dark room as the eyes ability to perceive blue is temporarily disabled. This never happened while looking at an LED before.


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## Lite_me (Jul 9, 2007)

Here is the warning sticker on my _COAST_ Led Lenser. It's well warranted too.


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## jboydjr (Jul 9, 2007)

There is an article regarding the occulars risks of HBLEDs (High Brightness LEDs) http://www.em.avnet.com/ctf_shared/sta/df2df2usa/LightSpeed-Eskow-0607.pdf

I don't know why the link is all goofed up, but I hope it works


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## WadeF (Jul 9, 2007)

jboydjr said:


> There is an article regarding the occulars risks of HBLEDs (High Brightness LEDs) http://www.em.avnet.com/ctf_shared/sta/df2df2usa/LightSpeed-Eskow-0607.pdf


 
Thanks for everyone's input. The artice was interesting, but he states that they found it wasn't the brightness of the sun, but "the short-wavelength light acccompanyng it. Blue light and shorter wavelengths ca be 1,000 times more dangerous than IR radiation."

It sounds like some here are saying the LED's aren't emitting light in these dangerous wave lengths? If that's they case, I'm not sure why the author of this article says your eyes could be damaged just from the intensity of the light.


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## yellow (Jul 10, 2007)

anyone has a link to the seller of leds being bright enough to cause eye damaye?

My 1A cree and SSC mods are still too dim
(imagine a single emitter bike light: small, endless runtime and bright as the sun)


some ppl seem to have too much time to think unnecessary problems over and over


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## fluke (Jul 10, 2007)

Lite_me said:


> Here is the warning sticker on my _COAST_ Led Lenser. It's well warranted too.



One of Jay's (FlashCrazy) Hocus Focus should have 2 or 3 of those stickers


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## Canuckle (Jul 10, 2007)

Duplicate post deleted.


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## Canuckle (Jul 10, 2007)

dano said:


> All the LED based Streamlight models have a warning sticker that says the LED's radiation level may cause eye damage...
> 
> Couldn't comment on the specifics, though.



Radiation?

Well, let's not forget that visible light is also, _technically_, radiation.

There's UV radiation.
There's IR radiation.
There's ionizing radiation..., and you don't want to go near that one.


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## Monocrom (Jul 10, 2007)

This forum = Tons of folks who each own multiple LED lights.

If eye damage was a real problem, we would have heard about it by now.

As for the Streamlight warning that dano brought up.... I'm thinking a lawyer in their legal dept. came up with the idea for putting that on their lights to prevent a lawsuit. You know, like the warning on fast food coffee cups that say "Caution: Contents are very hot." Ever since that one elderly idiot burned herself and then sued because the coffee was _too _hot. (BTW, I'm very familiar with the details of that case. And I still say it was her own fault). 

LEDs cause eye damage,
Cellphones cause brain cancer,
French fries cause hear attackes,
And 3 out of 3 people will die.... sometime during their lifetime. 

The horror, the horror....  :ironic:
~~~~~~~~~~~~~~~~~~~~~~

I think I need to clarify my post a bit. It just annoys me when people make unfounded claims. To say LEDs are dangerous without being able to cite a source where others could research the info for themselves, just plain annoying. It's one thing to say, "I won't use LEDs because I feel they're dangerous." It's another to make one's opinion sound like fact.


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## jtr1962 (Jul 10, 2007)

Monocrom said:


> And 3 out of 3 people will die.... sometime during their lifetime.


This reminds me of a government-funded study I heard about in the 1970s (a time when governments were giving grants for just about anything). The conclusion of the study was indeed that 100% of people will die sometime during their life. :laughing:


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## Abrams.357 (Jul 10, 2007)

WadeF said:


> I couldn't find any articles to back this up, other than blue and green LED's being bad, but I'm talking about white LED's.


how are blue and green leds bad?


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## fluke (Jul 10, 2007)

Abrams.357 said:


> how are blue and green leds bad?



Due to the fact the drink to much alcohol


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## TMorita (Jul 11, 2007)

I always thought that emitters on stars would make good shuriken with a little practice.

So I'm pretty sure you could cause some pretty decent eye damage with one. 

Toshi


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## WadeF (Jul 11, 2007)

Abrams.357 said:


> how are blue and green leds bad?


 
I only articles I could find claiming LED's could be bad for the eyes were about green and blue LED's. They were talking about the blue LED's being used on monitors, computers, etc, being bad. I don't know if there is any truth to it.

Here's the article, could just be BS:

http://interface.blog.com/612269/


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## 2xTrinity (Jul 11, 2007)

I believe blue light is going to be the most prone to causing retinal damage of the _visible_ wavelengths because the shorter the wavelength, the more potentially damaging it is as the photons that compose the light at shorter wavelengths are more energetic. Also, the eye's sensitivity to blue is quite low, so if the only light source in a room is a blue LED, then the pupils will tend to be dilated, allowing in a greater dosage. However, it is not blue light itself that is the problem as much as _high intensity_ blue light. In nature there really are no blue point sources, as blue light from the sun is attenuated and reaches the earth as evenly dispersed sky light. UV is attenuated even moreso than blue light (the very dangerous high-energy rays are absorbed, and what makes it through will tend to be extremely scattered/diffused as rayleigh scattering of light in the atmosphere is proportional to the inverse _fourth power_ of the wavelength)

The case in which I would see blue LEDs being a problem would looking directly into very poor quality emitters -- the sort that are more "whitish blue" than cool white. Good high-power LEDs that are more of a ~5000K neutral white will not be nearly as much of a problem, as they are so much brighter, the pupil will tend to constrict more if exposed, reducing the received dosage of blue light compared to exposure to a crappy 8000K LED. However, if one were to compare an LED to a HID lamp, or even halogen-incandescent of the same apparent color temperature and intensity, I believe the LED would be safer in almost every case. That is because the LED has almost zero light below about 450nm, whereas HID lights have a strong spike of violet light in the ~420nm, and both HID and halogen-incandescent, if not used with a proper UV-filter, release significant amount of shortwave UV energy. As LEDs move away from nasty blueness toward neutral white, I believe this issue will become largely irrelevant in reality, but that probably won't do anything to stop scare tactics (just look at how many articles there are about CFLs being highly dangerous toxic cesspools of mercury).



> There is an article regarding the occulars risks of HBLEDs (High Brightness LEDs) http://www.em.avnet.com/ctf_shared/s...Eskow-0607.pdf


This article mentioned UV LEDs intended for use in germicidal lamps as being the most dangerous, and with that I would certainly agree. Germicidal lamps release very short wavelength UV, the variety that causes sunburns. Exposure to that sort of wavelength from a point-source is far more dangerous than even pure blue LEDs as the UV rays would be almost completely invisible (no blink reflex and no pupil response is worse than minimal pupil response) to eyes and much more damaging -- similar to arc-welding without proper protection but _without_ a bright arc to cause a blink reflex.

I certainly hope that damage caused by UV LEDs in weird cases like that is not used to try to scare people away from using perfectly safe white LEDs in flashlights and household lighting. There is no reason LEDs cannot be made at least as safe or safer than conventional incandscent and fluorsecent lights.


Ultimately though, the danger comes from a combination of blue/violet/UV light _and_ high intensity, while I am very wary of using UV LEDs higher-powered than 10mA coin cells used to check $20 bills, I would not worry at all about using a fluorescent black-light at the same wavelength as the radiation is diffused in that case.


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## hank (Jul 11, 2007)

Don't believe the logic that if it could hurt you, the young folks here would be crying about it. It's an issue of cumulative lifetime damage. People who spend more time outdoors get blind more often as they get old. The best guess is that's from excess blue as well as UV light. It may be also an individual susceptibility.

Remember, those of you who believe in natural selection, it doesn't happen, after the years in which people have children. Through the years during which you can reproduce, selection's been working to favor your being in good health. After those years, there's no selection pressure for individual survival except, perhaps, our value as grandparents, and that's arguable.

The issue's still open, but there's good reason from the animal work to expect that over a lifetime, retinal damage accumulates from high energy photons including both the short wavelength blue and the shorter ultraviolet. 

Remember, a few hundred years ago, age 50 was quite old. We don't _have_ information about what damage accumulates that shows up after that age, yet, in any reliable sense. All we know is everything does take damage over time and eventually wears out. Your retina should be immune to this? No.

The blue is the driving source for white LEDs.

The concern is that the same visual pigments that make our vision work also react to high energy photons by becoming damaging chemicals.

Macular degeneration is the major cause of blindness with increasing age.

Our normal lenses slowly get yellower, blocking more blue light, with age.

This is from a decade ago; the newer articles I found with Google Scholar are all behind pay-per-view walls. I think this is still accurate:
http://www.springerlink.com/content/nh55950232lj1211/

Remember --- like sunburn, like breathing the wrong kind of smoke, it's not the immediate effect that's a concern here, it's what happens over the longer term with exposure.


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## Ice (Jul 13, 2007)

Well, I'm no specialist, but I thought LEDs produce more or less just one specific wavelength and white light (a combination of multiple wavewlengths) is being produced by a phosphor layer on top of the LED. And for that you need a primary light with higher energy than every wavelength that is emitted by the phosphor, so you need blue or even better UV light.
And if you have a LED die emitting UV light there will allways be a small percentage penetrating that phosphor layer unchanged. So there should be more UV light with LEDs than with bulbs, and that can be dangerous...


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## 2xTrinity (Jul 13, 2007)

Ice said:


> Well, I'm no specialist, but I thought LEDs produce more or less just one specific wavelength and white light (a combination of multiple wavewlengths) is being produced by a phosphor layer on top of the LED. And for that you need a primary light with higher energy than every wavelength that is emitted by the phosphor, so you need blue or even better UV light.
> And if you have a LED die emitting UV light there will allways be a small percentage penetrating that phosphor layer unchanged. So there should be more UV light with LEDs than with bulbs, and that can be dangerous...


Current LEDs are based on blue light in the 450-470nm range, they emit ZERO ultraviolet radiation (typically considered 380nm and shorter). Cheap white LEDs are often strongly bluish, and I believe these may cause some problems due to chronic exposure in a specific group of people prone to macular degeneration. The best phosphor LEDs however convert the majority of the blue output to yellow-green light, which means both less blue light is emitted, _and_ the eye is less likely to absorb as much, as the heighted yellow/green emissions cause the light to appear brighter, and thus the eye to have a greater pupil response than from the bluish LED (which would appear quite dim by comparison). Two-phosphor mixes that have been prototyped in labs are even better -- producing a more neutral color temperature with much better color rendition. 

Some have actually proposed using a UV LED with three phosphors (similar to how a fluorescent lamp works), but I believe such an LED would be very dangerous -- as leaking UV from a point-source can cause damaging UV radiation to be concentrated onto a single spot on the retina. To demsontrate this, consider which is more painful to look at -- a cool white fluorescent tube on a building by the side of the road, or the direct beam from a car with 35W HID headlights -- both have similar spectrum and lumen output. As far as I know, none of these UV-based LEDs have been produced except as prototypes.


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## Illum (Jul 13, 2007)

white LEDs will cause temporary blindness, often lasting for hours before complete recovery if the exposure was long enough...I think your friend might be referring to the Nichia 2W UV led


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## LED_Thrift (Jul 13, 2007)

WadeF said:


> ... Blue light and shorter wavelengths ca be 1,000 times more dangerous than IR radiation."


 
blue *and shorter* wavelengths: shorter than blue approaches or equals ultra-violet; and yes that is more dangerous than IR.


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## 2xTrinity (Jul 13, 2007)

LED_Thrift said:


> blue *and shorter* wavelengths: shorter than blue approaches or equals ultra-violet; and yes that is more dangerous than IR.


These kinds of vague statements in the journal articles I've seen on the topic make me wonder how much of the damage is really due to blue light, and how much is due to violet or UV when talking about "combinations" of blue and UV. In one study, I believe they took some eyes from a cadaver, and irradiated them with a high intensity beam from a mercury vapor lamp, at 430nm and their results suggested that it caused some damage as a result. However, comparing blue light at 430 to the blue in white LEDs which peaks at 450nm, or blue-only LEDs that usually peak at 475nm is not the same thing. The eye is about 4 times more sensitive to 475nm, so if one were to compare a 430nm light source that was just as bright in perceived intensity to a 475nm light source, the 430nm would both require almost 4 times as much radiant power to make up for the difference in the eye's sensitivity. Furthermore, the fact that 430 represents an even shorter wavelength means it should be more dangerous than 475nm photons. Also, it seems like there are a lot of different definitions of "blue" out there -- some sources refer 450nm or shorter, others 470 or shorter, and in still other cases, 500nm or shorter (500nm is sort of a cyan shade). 

One of the problems with looking at things like lifelong chronic damage due to blue light over time is that it seems like that sort of hypothesis seems like it would be very difficult to find real-world cases that adequately controlled enough to draw these conclusions. For example, it's definitely clear that people who spend a lot of time outdoors without proper eye protection are at greater risk for eye problems. Now how much is this due to UV exposure, or exposure to high-intensity glare, or exposure to blue light? For example, I would like to know if my preference of wearing neutral tinted sunglasses when outside puts me at a statistically significant risk compared to someone who wears otherwise identical sunglasses but with brown lenses that selectively block blue light. (both glasses have 100% UV-filtering, and both are polarized to selectively block specular reflections and scattered light).


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## Opto-King (Jul 24, 2007)

In Europe you have laser class directives regarding LEDs, which you do not have in the US (strange but true).

According to these directives all LED lamps which are laser class 2 or higher has to have a warning sticker on the lamps. But if you have an LED with laser class 1 you do not need to have this sticker due to that the LED is safe.

If you look at the LED datasheets most of the LED suppliers have the laser class information printed.


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## half-watt (Jul 24, 2007)

Opto-King said:


> In Europe you have laser class directives regarding LEDs, which you do not have in the US (strange but true).
> 
> According to these directives all LED lamps which are laser class 2 or higher has to have a warning sticker on the lamps. But if you have an LED with laser class 1 you do not need to have this sticker due to that the LED is safe.
> 
> If you look at the LED datasheets most of the LED suppliers have the laser class information printed.





what is the likelihood of potential laser-like damage to the retina from LEDs of laser class 2 [or higher - if any are rated higher???]?


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## Handlobraesing (Jul 24, 2007)

7up says shooting the bottle lid into your face, someone else's face or pets may cause an injury and not to point at yourself, people or pets.


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## half-watt (Jul 24, 2007)

Handlobraesing said:


> 7up says shooting the bottle lid into your face, someone else's face or pets may cause an injury and not to point at yourself, people or pets.




looks like you're a big proponent of one of nature's most precious vanishing natural resources...

COMMON SENSE!!!


couldn't agree with you more! THINK! THINK! THINK! as a friend of mine is fond of muttering to himself!!


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## Opto-King (Jul 24, 2007)

half-watt said:


> what is the likelihood of potential laser-like damage to the retina from LEDs of laser class 2 [or higher - if any are rated higher???]?


 
I'm not sure, how could I be?
The EU directive is more or less based on LED lamps with a "naked" LED, meaning they are not using a 2nd optics. This because if you (the user) peels off the 2nd optics from the lamp it still has to be safe for you to use.

I don't make the rules, I only read them...


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## Pistolero (Jul 24, 2007)

I recently bought a Inova x5 blue off Blindasabat on CPFM (thanks dude) and I'm a bit alarmed that it illuminates flurorescent stuff in a similar manner as a UV light. I don't have many high-end/high-powered lights, but from time to time my 1.5yr old daughter does get a hold of them. 

I think I'll have to keep this one locked up. :|

But yeah, common sense is not to stare into emitters that are on. 



half-watt said:


> couldn't agree with you more! THINK! THINK! THINK! as a friend of mine is fond of muttering to himself!!




My daughter and I watch "Tigger and Pooh" whenever it's on. I find myself going "THINK, THINK, THINK!" all the damn time now. Drives the wife crazy.


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## half-watt (Jul 24, 2007)

Opto-King said:


> I'm not sure, how could I be?
> The EU directive is more or less based on LED lamps with a "naked" LED, meaning they are not using a 2nd optics. This because if you (the user) peels off the 2nd optics from the lamp it still has to be safe for you to use.
> 
> I don't make the rules, I only read them...





many thanks for your reply. so sorry, to have troubled you with my query.


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## elgarak (Jul 24, 2007)

Opto-King said:


> In Europe you have laser class directives regarding LEDs, which you do not have in the US (strange but true).
> 
> According to these directives all LED lamps which are laser class 2 or higher has to have a warning sticker on the lamps. But if you have an LED with laser class 1 you do not need to have this sticker due to that the LED is safe.
> 
> If you look at the LED datasheets most of the LED suppliers have the laser class information printed.


Well, the strange part is that LEDs are included in the European regulations. What happened is that they wanted to outlaw laser pointers to be abused by kids. So they reformulated the laser regulations. But, being politicians and lawyers, and not MDs, scientists and engineers, they came up with a definition that happened to include LEDs as well as laser diodes.

Most professionals I know consider the current regulation ridiculous because of this -- it does not say anything about the danger of the device due to the inclusion of safe/less dangerous devices in the same class as truly dangerous ones.


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## half-watt (Jul 24, 2007)

elgarak said:


> Well, the strange part is that LEDs are included in the European regulations. What happened is that they wanted to outlaw laser pointers to be abused by kids. So they reformulated the laser regulations. But, being politicians and lawyers, and not MDs, scientists and engineers, they came up with a definition that happened to include LEDs as well as laser diodes.
> 
> Most professionals I know consider the current regulation ridiculous because of this -- it does not say anything about the danger of the device due to the inclusion of safe/less dangerous devices in the same class as truly dangerous ones.




many thanks for the clarifying remarks. they sure put the OP info into context.


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## Pax et Lux (Jul 25, 2007)

I'm sorry to muddy the waters further here, but the answer could be as simple as it's HID lights that have the potential to cause eye damage (because, I believe they emit a wider range of radiation) and someone, somewere confused HID and LED or thought they were one and the same.

Of course, I'm not sure about the radiation leaving an HID light, but I seem to remember reading something on Flashlightreviews.com sometime ago about it being unadvisable about looking into the light - which it is, with any flashlight, really. When I get time I'll try to find it.


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## Luminescent (Jul 25, 2007)

The DANGER presented by high brightness IR and UV LED’s is very REAL.

When I saw that DX was offering 1W level UV LED emitters, I immediately envisioned some poor jerk wiring one of these things up, and over-driving the crap out of it while staring into it and wondering why it didn’t look ‘brighter’ (only to discover in very short order that NOTHING looks bright anymore because all his central vision is GONE).

DO NOT MESS WITH HIGH BRIGHTNESS IR OR UV SOURCES, UNLESS YOU HAVE PROTECTIVE EYEWEAR AND KNOW EXACTLY WHAT YOU ARE DOING. 

As far as what may be driving objection to high brightness *WHITE LED's* goes, I think there are really TWO different issues:

1. Modern high brightness LED's have an extremely high surface brightness level which should not be viewed directly even briefly. Fortunately, the blink reflex is likely to protect the eye (except for high brightness IR and UV LED's as noted above).

2. Even when viewed indirectly, very bright LED sources may have some ergonomic viewing fatigue issues due to the spectral distribution of the light.

Number 1 above is a very real concern for UV and IR LED's (because pupil contraction and the blink reflex does not work for these sources), but seems a little silly to apply to high brightness white LEDS, because any moron who is so determined to destroy his or her vision, by staring into a bright white LED, can just as easily go outside and stare into the sun to accomplish the same purpose (so banning bright white LED's to protect these idiots from themselves doesn't make any sense).

I think the second issue is pretty minor as well, but to understand the concern, take a look at the Wikipedia entry on LED’s and note that the spectrum chart for a ‘White’ LED actually has a really huge blue spike (caused by leakage of the blue driver through the phosphor layer).

Here are the links to the main article and the full size spectrum plot:

http://en.wikipedia.org/wiki/Light-emitting_diode

 http://en.wikipedia.org/wiki/Image:White_LED.png


The statement that white LED's emit ZERO UV is a bit of an oversimplification.

Having tested laser and led components professionally, I can tell you that an LED's output spectrum is quite wide and varible (due to process control issues).

The Blue light leakage spike in a white LED borders on the 400nm region that represents the boundary of the Near-UV to start with, and with the wide spectrum (and process control variations in the manufacturing of LED's), some LED's will almost certainly leak some energy which extends into the near ultra-violet.

As someone has already commented, 'white' LED's are really great at exciting fluorescence in 'day-glow' colors, and this behavior is no doubt a result of leakage of these highly energetic blue-violet spectral components through the phosphor.

Even if the spectrum is on spec, the ultra bright blue light is quite actinic (able to excite photo-chemical effects), and could cause viewing fatigue or even 'snow-blindness' if viewed at high brightness for extended periods.

I personally find the spectrum from white LED lights slightly irritating to use unless I keep the brightness reasonable, and use 'warm' color balance LED's (where more of the optical energy has been shifted into the longer wavelengths).
[FONT=&quot]
Certinly, dispite the strong blue-violet component, LED illumination is not as dangerous as say, unfiltered sunlight for example, so I don’t think it makes any sense to go overboard on this second issue, as long as folks show a little common sense. 

Despite the above facts, there will no doubt be some self-appointed ergo-nazi twits who will seek to legislate to protect us from the evils of artificial light. Of course, If we listen to these luddites, it would probably be better that we should avoid ALL artificial technologies and live happily as nature intended (short brutal lives, in cold dark caves).[/FONT]

[FONT=&quot]On the other hand, once again (at the risk of repeating myself) UV and IR LED's are a different matter; 

PLEASE DO NOT MESS WITH HIGH LEVEL IR OR UV SOURCES, UNLESS YOU HAVE PROTECTIVE EYEWEAR AND KNOW EXACTLY WHAT YOU ARE DOING.[/FONT]


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## Led_Blind (Jul 26, 2007)

Those that promote laws that 'are for your own good' are the bottom feeders of society. They actively attempt to dumb down the issues and fear knowledge (they'd be out of work). Here's an odd warning, I purchased a good quality knife set recently. It contained the warning 'Not intended for human or animal use' .... ummm huh?

I was recently with a 6yr old cousin in a shopping centre eating a doughnut treat. Little Leah after finishing her own went to pinch what was left of my own and received a very quick but playful slap on the hand and proceeded to guilt me through facial expression. It was at that point that some nosey old menopausal bag comes along and gives me an ear full for spanking my child in public. This in turn attracted the attention of the shopping centre security who quickly came to the conclusion that I was a bad father. 
My little cousin decided she did not like these people and said to me "that old lady is scary, can we go now?" My response “Yeah, just a sec” I overtly took down the badge numbers and names of the guards with no explanation, turned and left hand in hand with Leah. 

Sorry for the rant but the basic issue is the same, think before you act. If you cannot envisage the issues or problems then research and understand. If done you can play with all manner of dangerous toys and be fine. This includes playing with high powered UV or IR sources that can be fun, educational and SAFE. I think Luminescent already said this tho…. 

Oh and one more titbit, I am (unwillingly) and occupational health and safety officer for our office. This involves attending mandatory training days discussing of all things, adequate signage for dangerous situations. One that came up was the requirement that there be a sign indicating a smooth kitchen floor would become slippery when wet and all spills should be cleaned immediately. Ok fair enough, clean up your spills because it is obvious that a wet floor is more slippery, unhygienic and unsightly. When I commented that slippery when wet was common sense so unneeded i was asked what common sense was my response was “it is the knowledge that tells you not to look down the barrel of a loaded gun to see why it was not firing” The trainer had no comeback.


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## CdBoy (Jul 26, 2007)

Stare into any Light Source for a looong time and tell me if your eyes is still ok or not and i will tell you "you are one crazy guy!" heh heh.

do everything in moderation is the old adage that is.


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## WadeF (Jul 26, 2007)

Luminescent said:


> The DANGER presented by high brightness IR and UV LED’s is very REAL.


 
Could you comment on some of the UV lights shown here?

http://www.lighthound.com/index.asp?PageAction=PRODSEARCH&txtSearch=uv&btnSearch=GO&Page=1

I have the 12 LED one, and the smaller key chain model. Are these dangerous to shine around and look at items light up from these lights without protection? Or are these no worse than being around black lights?


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## Monocrom (Jul 26, 2007)

WadeF said:


> Or are these no worse than being around black lights?


 
I've seen lights like that before.... You pretty much hit the nail on the head with your last sentence, Wade.


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## orionlion82 (Jul 26, 2007)

Luminescent said:


> (Snip!)
> 
> Despite the above facts, there will no doubt be some self-appointed ergo-nazi twits who will seek to legislate to protect us from the evils of artificial light. Of course, If we listen to these luddites, it would probably be better that we should avoid ALL artificial technologies and live happily as nature intended (short brutal lives, in cold dark caves).[/FONT][/FONT][/SIZE][/FONT]
> 
> ...



_
From Rainer Maria's "better version of me" - Artificial Light. 

no one defies artificial light.
simultaneous sitting 'til you atrophy
maybe you try to be pretty instead of kind
why is this technology an anathema to me?
if i could just breath it out....
i could always breathe back in
i'll cut all your wires
i never cared
cut all your wires
what can be there? it's dead.
and all the invisible arcs
are caught in my head
and the invisible arcs
are caught in my head
_
it works out as a good MSDS for instructional purposes here. 

i just happened to be listening to it while i read the thread ironically enough...

note the reccomendation to allways breathe back in as well! 
its a saftey song! 
and the more you read in to it the more it applies in this context to this thread. fascinating when you study it carefully and think about what we are talking about here...


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## brightnorm (Jul 27, 2007)

Craig (LED MUSEUM) answers the question of UV radiation in the spectral charts included in many of his reviews. I looked through about a dozen and found that with remarkable consistancy all of the lights produced very little UV. 

Here's an example (Fenix P3D-CE)

http://ledmuseum.candlepower.us/ninth/p3d1.gif

I can't say this is representative of all LED lights, but it certainly appears encouraging for those of us who fear UV overexposure. A question that remains is whether those same curves apply when the lights are run at greater intensities. 

Brightnorm


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## orionlion82 (Jul 27, 2007)

brightnorm said:


> Craig (LED MUSEUM) answers the question of UV radiation in the spectral charts included in many of his reviews. I looked through about a dozen and found that with remarkable consistancy all of the lights produced very little UV.
> 
> Here's an example (Fenix P3D-CE)
> 
> ...



well, overdriving any component/assembly throws the rulebook out the window and you are on your own.


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## Handlobraesing (Jul 27, 2007)

orionlion82 said:


> well, overdriving any component/assembly throws the rulebook out the window and you are on your own.



Not in the US civil court.


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## Quickbeam (Jul 27, 2007)

"In Europe you have laser class directives regarding LEDs, which you do not have in the US (strange but true)."

Not strange at all to me. The US isn't (yet) a huge nanny state like most Euorpean countries that feel the need to tell everyone what they can and can't do "for their own good". Although we're trying like heck to get there, aren't we...

White, blue, and green LEDs are not going to cause eye damage if you use common sense and listen to your body. If it's bright and we look at it, we have a natural aversion reaction (we blink and look away). The effect is no worse than momentarily looking at the sun by accident and turning away. 

I lump those warnings I see on LED lights in the same class as those found on my wife's hair dryer that say "do not use while sleeping". Stupid and useless. "Do not stare into beam". No kidding... Duh.

You may also find with a little searching that the information that some folks quote about blue and green LEDs being dangerous is actually from research into the danger of blue and green LASERS, not LEDs. The research evidence is frequently expanded by do-gooders to encompass LEDs in addition to LASERS, which is completely incorrect.


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## half-watt (Jul 27, 2007)

Quickbeam said:


> The research evidence is frequently expanded by do-gooders to encompass LEDs in addition to LASERS, which is completely incorrect.




You mean to tell me that they're NOT the same thing? They both begin with the letter 'L', don't they?


sincerely yours,
Mr. D. O. Gooder


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## Luminescent (Jul 27, 2007)

WadeF said:


> Could you comment on some of the UV lights shown here?
> 
> http://www.lighthound.com/index.asp?PageAction=PRODSEARCH&txtSearch=uv&btnSearch=GO&Page=1
> 
> I have the 12 LED one, and the smaller key chain model. Are these dangerous to shine around and look at items light up from these lights without protection? Or are these no worse than being around black lights?



[FONT=&quot]There are several things working in your favor to make this style of light safer.

First, lights like the one you posted the link to should be designed to only produce long-wave UV, which is much safer than short-wave UV (this is the UV-A / UV-B issue you have probably heard about). On the other hand, some portable lights are produced for mineral prospecting, which requires short-wave UV, so if you see references to a UV light being sutible for that purpose, look out!

[/FONT][FONT=&quot]Second UV LED technology is only slowly catching up with the ultra bright visible light LED devices, so your UV LED's are probably nowhere near the UV equivalent of those 100000mcd white LED's which are so blinding bright in the visible spectrum. This is why you can just barely get something across the room to fluoresce (a single 40 Watt Long Wave UV fluorescent light will have a hole room glowing very brightly by comparison). So, fortunately, the UV level produced by this type of light is fairly moderate.[/FONT] [FONT=&quot] 

Third, your light uses multiple 5mm LED's which spreads out the source brightness, which is nowhere near as bad as looking into a single 1W high power device.

So using your light to illuminate items for close-up examination should be perfectly safe, if you keep the duration of exposure reasonable, and use a little common sense.[/FONT][FONT=&quot] For example, I would not look directly back into the light if you can avoid it, as that's the worst-case scenario.[/FONT]


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## Monocrom (Jul 27, 2007)

Anyone *still* worried about the effects of LEDs, should go back and re-read post #53.


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## Daviesow (Apr 9, 2010)

Regarding statements such as this:



Luminescent said:


> ...because any moron who is so determined to destroy his or her vision, by staring into a bright white LED, can just as easily go outside and stare into the sun to accomplish the same purpose (so banning bright white LED's to protect these idiots from themselves doesn't make any sense).



I couldn't agree more with the basic message that those who have been given some common sense should be expected to use it. However, in throwing around terms like "moron" and "idiot" you seem to be forgetting that some people, through no fault of their own, just don't have any common sense.

I have three young children; the youngest is just a few months old. Now I could sit him down on the floor and hold warning labels in front of his face. I could yell "You had better not look straight into this lamp young man!" till I am blue in the face. Somehow I don't think this will have any effect on his natural tendency to stare into bright lights.

The point is, people concerned about the blue light damage are not just worried about specialty lamps and toys. These can obviously be kept away from children. The concern is with the screw-in incandescent replacement bulbs being put into use throughout the home.

So, yeah, if my son were in his 20s and spending a lot of time staring straight in to newfangled light sources I'd go ahead and join you in calling him an idiot and a moron. But for now, give him a break...

Unfortunately, this means "Just don't do it" isn't a very helpful answer to the question of what looking at these sorts of light sources will do to your eyes.


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## Stress_Test (Apr 9, 2010)

From CREE's website, regarding LED and eye safety:

http://www.cree.com/products/pdf/XLamp_EyeSafety.pdf


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## BigBluefish (Apr 9, 2010)

Stress_Test said:


> From CREE's website, regarding LED and eye safety:
> 
> http://www.cree.com/products/pdf/XLamp_EyeSafety.pdf


 
Looks like the XP-E is the way to go, if you're concerned about risk from blue light exposure. 

I'd say best to keep all (even your low-lumen output) LEDs away from the kids.


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## Per-Sev (Apr 9, 2010)

So I am really confused here do we stare into our lights or don't we, I like to sit down in the evening and turn out all the lights and stick my light in my eye turn it to high and just look at all the pretty colors so now your saying that's bad, next your going to tell me that playing Russian roulette my semi auto Glock is dangerous. Make up your mind please I can't have any fun now.


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## smithman (Apr 9, 2010)

In my point of view the REAL DANGER of LED Flashlights come from another thing: 
Its the reflection of different kind of surfaces which could cause hard damage to your eyes, because in the normal environment its quite impossible to use a flashlight without touching elements which are reflecting.

I am sure that every flashlight-user get such reflections, at least once a months.


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## BytorJr (Apr 10, 2010)

If any of my flashlights cause eye damage I'd be shocked. My "newest" is an "old" Malkoff M60 drop-in and the Novatac 120P. 

Now, seriously, how many of you all have been to the eye doctor where they get the light AND lens out after you with your eyes dilated? THAT is seriously bright.


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## smithman (Apr 10, 2010)

Your doc have a special light with specs he is allowed to use. 
Dont compare it to our Cree Q5/R5 stuff.. 

People have to be very careful, especially flashaholics!  
Thats a serious topic, nothing for kidding.


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## Monocrom (Apr 10, 2010)

Well, since the last time I posted in this thread (nearly 3 years ago) my addiction to lights has gone up. My eyes still work. 

If someone decides to respond to another post 3 years from now, I'll update you all on the condition of my eyes.


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## yellow (Apr 10, 2010)

smithman said:


> the REAL DANGER of LED Flashlights
> * reflection *of different kind of surfaces


come on


Eye damage = high damage in shorter time than *blinking reflex*
*... that is only possible with LASERS*
(with them even a reflected beam dangerous, thats correct)


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## smithman (Apr 10, 2010)

I dont think so. Never underestimate the huge power of latest LEDs. 
Even 60+ Lm could be enough.

There are too many surfaces which are reflecting in a dangerous way. 
For example any kind of metallic and glass-type elements .

For sure, if your in the jungle of brazil you won't notice any kind of reflection, 
but under normal circumstances you have such elements in every general-usage environment.
The quantity of the usage could harm your eyes more than one or two times of getting snow-blind by the flashlight.


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## MikeG1P315 (Apr 10, 2010)

If reflective surfaces are the issue, then LEDS are no different than all other flashlights, headlights, and the sun. I've been plenty blinded by reflections on chrome bits of cars or windshields by sunlight, headlights, etc. 

I suspect staring at any bright source of light for long periods of time is a bad idea… but, um, even damage caused by looking at the sun at high noon WTHOUT sunglasses is usually minor and temporary. (with sunglasses, or durng an eclipse is another story entirely).


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## Thilo (Apr 11, 2010)

Yes and no, fact is that any light what is powerfull can be damage your eye power, that can be also a Xenon light or a normal spot. Let us review a few basic parts of the eye that are important to understand, what a strobe is, and what happens when the eyes get "streamt". The eye has the ability to adjust itself very quickly to a steady light. Therefore, the advantage to blind the attacking person gets lost. It becomes harder for the eye to fix on a target behind the light or to determine the distance to the source. The light can thus be used as a protective "shield"


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## Monocrom (Apr 11, 2010)

Thilo said:


> . . . The light can thus be used as a protective "shield."


 
For about one second.

Please, this issue has been done to death on these boards. Unless you're using your flashlight to physically strike an attacker, a light is a p*ss poor choice for self-defense.


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## Misan (Apr 12, 2010)

I think every bright light can damage eye. Not in vain to protect the eyes from the sun we wear sunglasses. Not correctly configured in the car headlights too irritating to the eyes. 
Do not do poop and eyes will be all right.


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## Mr Bigglow (Apr 12, 2010)

You can't go around selling the multitudes flashlights that say things like "do not looking directly into beam" without some such eye destruction belief building up. And of course the warning is necessary to preclude some hysteric suing the company because the spots didn't go away. But you might as well say that using hammers damages vision, since you can't buy one of those that doesn't advise donning eye protection before using.


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## Apollo Cree (Apr 13, 2010)

This may be related to the "blue light hazard." The concern is that if you start using the current "white" LED's for room lighting there might be long term eye health problems due to the high amount of blue light in certain wavelength bands. 

This is a concern about what happens if you're exposed to blue-rich light for 8 or more hours a day for years. Think of it as being analogous to fading of a carpet where it's exposed to the sun coming through a window. It takes a long time to happen, but it definitely happens. 

There is concern about the rate of macular degeneration, cataracts or other "aging" problems with the eye being increased. 

It's difficult to test because results take a long time, and the problems it may cause happen at a certain rate even without blue light hazard. 

There is some concern that blue light hazard may exist even with common fluorescent lighting. 

In my opinion, this is a valid concern, but it's not a "run for your lives" type of thing. Suppose that LED (or compact fluorescent) lighting increases the rate of macular degeneration by 10%, that would be thousands of people losing their vision.


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## lyyyghtmaster (Aug 7, 2010)

Triphosphor fluorescent peaks around 435nm and LED near 450. So which is worse? You'd think 435 for the same CCT since there would have to be more of it to create an overall white. But that is complicated by the presence of a moderate (less dangerous) cyan peak in the triphosphor spectrum, which would mean the deep blue peak wouldn't have to be as strong. Phosphor-converted white LEDs have a hole at this point in the spectrum. Also, with higher-CCT triphosphor fluorescents, there tends to be more broad-spectrum blue in addition to the above peaks, which would again result in less need for a strong 435 peak.


Along these lines I read somewhere recently that supposedly 440nm is at a peak of eye-damage-capability, presumably dropping off above (makes sense) and below (doesn't make sense). Could this actually be true that 440 might be somewhat more dangerous than slightly shorter wavelengths? I would tend to think the danger level increases pretty smoothly as shorter wavelengths are approached, but maybe this is an oversimplification? :shrug:


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## jk037 (Aug 7, 2010)

Just don't jam LEDs into your eye sockets and everything will be fine.


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## hank (Aug 7, 2010)

> I read somewhere ... 440 nm ...

Absorbtion peak, perhaps.

Try these: http://scholar.google.com/scholar?hl=en&q=440+nm+eye+damage


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## the.Mtn.Man (Aug 7, 2010)

WadeF said:


> LED = Eye Damage?


A sufficiently bright incandescent light can also lead to eye damage provided you stare at it long enough.


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## FloggedSynapse (Aug 7, 2010)

lyyyghtmaster; said:


> (...)
> 
> Along these lines I read somewhere recently that supposedly 440nm is at a peak of eye-damage-capability, presumably dropping off above (makes sense) and below (doesn't make sense). Could this actually be true that 440 might be somewhat more dangerous than slightly shorter wavelengths? I would tend to think the danger level increases pretty smoothly as shorter wavelengths are approached, but maybe this is an oversimplification? :shrug:



It's possible. Apparently blue/violet light, at least in large amounts, is much more damaging to the retina than green or red light.

Unfortunately the way these high efficiency white LEDs work is by converting a lot of ~450nm radiation (from the LED die) to white light (after passing through the phosphor around the LED). So they all have a lot of blue light in their spectrum, especially compared to more 'classic' light sources. I think it's part of the reason these lights are glarey. 

See this topic I started: LEDs & 'Blue Glare' & Eye damage
https://www.candlepowerforums.com/threads/282316

Also these two links of blue light damage:
http://www.sunnexbiotech.com/therapist/main.htm
http://www.sunnexbiotech.com/therapist/blue light and amd.html

According the above link(s) 440nm represents the most damaging wavelength - quickly 'bleaching' retinal cells, leading to many harmful biochemical reactions, release of free radicals, etc..

This is long term and cumulative damage, not instant blindness, being discussed.

Likely under normal use these lights are relatively safe.. but who knows they haven't been in common use long enough to know.

FYI


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## Apollo Cree (Aug 8, 2010)

We need to realize that there's not a "black and white" distinction between blue and ultraviolet light. (or between other light colors for that matter.) 

If you're talking about chemical effects of light of a specific wavelength, there's a bit of a sliding scale. 1 watt of red light has the least amount of chemical effects. Green light has a little more effect. Blue is more, UV is more, X-rays are even more. Even within a particular "color," there is a range of "damage levels." Deep ultraviolet is more chemically active than near UV. 

Think of it like a video game. Certain weapons have a "1" damage level. Some have a "100" damage level. The 1 damage level weapon will eventually kill you.

White LEDs have a strong peak in the blue region. It's a valid concern whether this has a long term bad effect on the human eye. Light, especially UV, seems to be correlated to cataracts and other long term "age related" eye problems. Even a small percentage increase in eye problems will mean a lot more cases of serious eye problems. Thousands of people could lose their vision prematurely years in the future. 

Suppose that 30 years in the future, we find out that converting all our indoor lighting to LED's caused the cataract rate in the US to increase 10%. That's 40,000 cataract cases per year. 

I'm not really all that concerned, but blue light hazard is a valid concern. I'm concerned that the risks will not be considered in the government's frenzy to conserve energy at all costs by converting everything to LEDs.


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## WDG (Aug 8, 2010)

I predict this can only end in sweeping draconian legislative nannyism, wherein we will all be forced to turn in our lights for Mag Solitaires and wear protective goggles at all times.


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## PayBack (Aug 8, 2010)

It all comes down to taxes... if you pay enough money to the government, you can even sell things that kill nearly 50% of it's users.


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## John_Galt (Aug 8, 2010)

I'm none too concerned about it. I don't make a habit of staring into the emitter end of my lights, for any period of time, and try not to do the same to others.

Nor do I strobe my friends, unless they ask me too... In which case it's _turn-on-strobe - flash-it-past-their-face - turn-off-strobe_...

And any legislative act to limit this would be pointless, un-enforceable, and total BS.

/thread


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## baterija (Aug 10, 2010)

Apollo Cree said:


> Suppose that 30 years in the future, we find out that converting all our indoor lighting to LED's caused the cataract rate in the US to increase 10%. That's 40,000 cataract cases per year.



...and the ad campaign would phrase it just that way if those were the numbers. .013% of the population has cataracts because of LED's doesn't make nearly as scary of a headline. 

Definitely an interesting possible side effect in the long term though.


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## Mr Bigglow (Aug 11, 2010)

Surely the wavelength output of LEDs is so controllable as to allow for zero UV emissions? And whatever the case I'm quite confident that I get at least 1000% more UV in one hour from the bright yellow object seen in the sky in daytime than I will from a lifetime of LED use.


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## bfvww2 (Aug 11, 2010)

2xTrinity said:


> I believe blue light is going to be the most prone to causing retinal damage of the _visible_ wavelengths because the shorter the wavelength, the more potentially damaging it is as the photons that compose the light at shorter wavelengths are more energetic. Also, the eye's sensitivity to blue is quite low, so if the only light source in a room is a blue LED, then the pupils will tend to be dilated, allowing in a greater dosage. However, it is not blue light itself that is the problem as much as _high intensity_ blue light. In nature there really are no blue point sources, as blue light from the sun is attenuated and reaches the earth as evenly dispersed sky light. UV is attenuated even moreso than blue light (the very dangerous high-energy rays are absorbed, and what makes it through will tend to be extremely scattered/diffused as rayleigh scattering of light in the atmosphere is proportional to the inverse _fourth power_ of the wavelength)
> 
> The case in which I would see blue LEDs being a problem would looking directly into very poor quality emitters -- the sort that are more "whitish blue" than cool white. Good high-power LEDs that are more of a ~5000K neutral white will not be nearly as much of a problem, as they are so much brighter, the pupil will tend to constrict more if exposed, reducing the received dosage of blue light compared to exposure to a crappy 8000K LED. However, if one were to compare an LED to a HID lamp, or even halogen-incandescent of the same apparent color temperature and intensity, I believe the LED would be safer in almost every case. That is because the LED has almost zero light below about 450nm, whereas HID lights have a strong spike of violet light in the ~420nm, and both HID and halogen-incandescent, if not used with a proper UV-filter, release significant amount of shortwave UV energy. As LEDs move away from nasty blueness toward neutral white, I believe this issue will become largely irrelevant in reality, but that probably won't do anything to stop scare tactics (just look at how many articles there are about CFLs being highly dangerous toxic cesspools of mercury).
> 
> ...



Thanks for you post. It was very instructive. Is the damage risk only comes from power and distance?


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## FloggedSynapse (Aug 19, 2010)

These LED lights produce a huge amount of blue light compared to more common light sources like incandescent lights and candles. The LED itself _only_ produces blue light in a narrow band of the visible spectrum (apparently most damaging to the retina - see my above post). After passing through the phosphor around the LED some of the blue light is modified to create white light.

It's easy to check this yourself. I can look at a candle flame (indefinitely) or glance at a 100 watt incandescent bulb, and when I turn away the afterimages fade almost immediately. However even a brief glance directly at an LED light leaves nasty lingering afterimages - evidence of how quickly the retina is bleached by these lights.

For home lighting I'm back to using incandescent lights or candles. Given the potential hazards of excessive amounts of blue light I'd hesitate to use LEDs for general purpose lighting around the house, etc (IMO).

About $1.00 will procure a glass candle which will burn for dozens of hours and provide a pleasing light - less than the cost of an Li battery.

CandlePower!

I still love my LED flashlights, just don't use them often.


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