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Thread: LED = Eye Damage?

  1. #1
    Flashaholic* WadeF's Avatar
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    Default LED = Eye Damage?

    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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    Flashaholic* LukeA's Avatar
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    Default Re: LED = Eye Damage?

    'Someone' is a wacko, IMO.
    A little madness never hurt anybody.

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    Flashaholic* Daniel_sk's Avatar
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    Default Re: LED = Eye Damage?

    Damn, just today I was looking into the L1D CE beam .
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    Flashaholic fluke's Avatar
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    Default Re: LED = Eye Damage?

    Who said that ?????
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    Flashaholic tussery's Avatar
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    Default Re: LED = Eye Damage?

    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.

  6. #6
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    Default Re: LED = Eye Damage?

    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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    Default Re: LED = Eye Damage?

    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

  8. #8

    Default Re: LED = Eye Damage?

    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.

  9. #9
    *Flashaholic* IsaacHayes's Avatar
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    Default Re: LED = Eye Damage?

    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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    Default Re: LED = Eye Damage?

    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.
    There's more to a light than its output.

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    Flashaholic* koala's Avatar
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    Default Re: LED = Eye Damage?

    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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    Flashaholic* Manzerick's Avatar
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    Default Re: LED = Eye Damage?

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

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    Default Re: LED = Eye Damage?

    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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    Flashaholic* Lite_me's Avatar
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    Default Re: LED = Eye Damage?

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

    "Success usually comes to those who are too busy to be looking for it."

  15. #15

    Default Re: LED = Eye Damage?

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

    I don't know why the link is all goofed up, but I hope it works
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    Flashaholic* WadeF's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by jboydjr View Post
    There is an article regarding the occulars risks of HBLEDs (High Brightness LEDs) http://www.em.avnet.com/ctf_shared/s...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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    Default

    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

  18. #18
    Flashaholic fluke's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by Lite_me View Post
    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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    Flashaholic Canuckle's Avatar
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    Default Re: LED = Eye Damage?

    Duplicate post deleted.
    Last edited by Canuckle; 07-10-2007 at 03:31 AM. Reason: Duplicate post deleted
    NKoTB..when it comes to flashlights

  20. #20
    Flashaholic Canuckle's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by dano View Post
    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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    *Flashaholic* Monocrom's Avatar
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    Default Re: LED = Eye Damage?

    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....
    ~~~~~~~~~~~~~~~~~~~~~~

    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.
    Last edited by Monocrom; 07-10-2007 at 01:19 PM. Reason: Clarification of post.
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  22. #22
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by Monocrom View Post
    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.

  23. #23

    Default Re: LED = Eye Damage?

    Quote Originally Posted by WadeF View Post
    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?

  24. #24
    Flashaholic fluke's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by Abrams.357 View Post
    how are blue and green leds bad?
    Due to the fact the drink to much alcohol
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    Default Re: LED = Eye Damage?

    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

  26. #26
    Flashaholic* WadeF's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by Abrams.357 View Post
    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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    Flashaholic* 2xTrinity's Avatar
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    Default Re: LED = Eye Damage?

    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.
    Last edited by 2xTrinity; 07-11-2007 at 06:36 PM.

  28. #28
    Flashaholic* hank's Avatar
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    Default Re: LED = Eye Damage?

    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.

  29. #29
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    Default Re: LED = Eye Damage?

    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...

  30. #30
    Flashaholic* 2xTrinity's Avatar
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    Default Re: LED = Eye Damage?

    Quote Originally Posted by Ice View Post
    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.
    Last edited by 2xTrinity; 07-13-2007 at 12:34 PM.

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