LED = Eye Damage?

[Monocrom]

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.

 

[jtr1962]

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:

 

[Abrams.357]

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?

 

[fluke]

how are blue and green leds bad?

Due to the fact the drink to much alcohol

 

[TMorita]

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

 

[WadeF]

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/

 

[2xTrinity]

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.

 

[hank]

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.

 

[Ice]

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...

 

[2xTrinity]

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.

 

[Illum]

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

 

[LED_Thrift]

... 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.

 

[2xTrinity]

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).

 

[Opto-King]

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.

 

[half-watt]

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???]?

 

[Handlobraesing]

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.

 

[half-watt]

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!!

 

[Opto-King]

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...

 

[Pistolero]

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.

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.

 

[half-watt]

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.