# Eye damage?



## jeffreyliu838 (May 12, 2009)

How many lumens does it take to damage the eye? Will direct exposure to 300 lumens do any damage within like 2 minutes? 

Thanks.


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## mmajunkie (May 12, 2009)

I have no idea, and don't want to find out.


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## american lockpicker (May 12, 2009)

Avoid UV lights they cause cataracts.


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## Mjolnir (May 12, 2009)

I don't think that an LED will output enough UV to seriously and permanently damage vision. It isn't really the amount of lumens that matters, since lumens is the visible radiation that a light gives off. The harmful wavelengths are in the UV range, and I doubt even a high output LED will give of more than a little UVA (I could be wrong). 
However, I believe most HID's give off some amount of UV light, so it would be best not to stare into one of those. 
Short arc lights definitely give off UV, but chances are you won't be looking into one of those anyway.


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## ImGeo (May 12, 2009)

More than just lumens, it depends on intensisty (lux)--or in other words, how close you put it to your eye.

Regardless, treat a flashlight like the sun. Though it's not exactly the same and has far less UV, it's never a good idea to stare at a bright light.

Furthermore, over the long run (I heard somewhere), staring at bright lights makes you more sensitive to light. This means when you go outside on a bright sunny day, your eyes will be overexposed, forcing you to have to wear sunglasses. (and yes, this personally happened to me. I used to be able to go outside even if its bright. Now, whenever its quite bright, I either have to wear sunglasses, or my eyes are way too bright and start to water... and I used to stare at lights)

disclaimer: what I said was mostly based on myself and some sources on the internet. I may be wrong.


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## Gunner12 (May 12, 2009)

jeffreyliu838 said:


> How many lumens does it take to damage the eye? Will direct exposure to 300 lumens do any damage within like 2 minutes?
> 
> Thanks.


It's not lumen you are looking for, it is how many lumen is emitted for the available emitting area. For example, a laser is low in lumen, but because it creates a lot of light from a tiny area, it can damage human eyes.

A 10 lumen laser will have a much much higher change of damaging your eyes then a 10000 lumen flood light (I'm thinking of multiple florescent tubes behind a diffuser).


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## Mjolnir (May 12, 2009)

Gunner12 said:


> It's not lumen you are looking for, it is how many lumen is emitted for the available emitting area. For example, a laser is low in lumen, but because it creates a lot of light from a tiny area, it can damage human eyes.
> 
> A 10 lumen laser will have a much much higher change of damaging your eyes then a 10000 lumen flood light (I'm thinking of multiple florescent tubes behind a diffuser).



You are right about the lux mattering, but that is still only visible light. The UV light is much more dangerous to eyes, but LEDs will not give off all that much. I don't think many of the lights any of us own output enough visible light to actually burn the eyes (from visible light only).

While a laser can actually burn your retina, a 300 lumen LED flashlight shouldn't focus on your retina enough to cause any serious damage.


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## GreyShark (May 12, 2009)

Yeah, if you think about it a 75 watt lightbulb is probably putting out around 1,000 lumens. The sun is cranking out, oh, I don't know, one hundred quadzillion to the third freak'n power mega-lumens(but is that bulb or torch lumens?). While I wouldn't recommend staring directly into them you can obviously operate in the area they illuminate safely so it isn't just sheer output.


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## jeffreyliu838 (May 13, 2009)

Ah. I was taking pics of my eye (I'm a photo nut) and I using my P3d on turbo as lighting to try to brighten up the shot...it was maybe less than an inch from my eye? Directly into my eye though...I don't really notice anything (maybe a little tenderness or dryness, nothing much), but I was just curious. From what you guys told me, it shouldn't be too damaging, right? Ehh...hindsight is 20/20 I guess, haha...

Thanks.


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## Dances with Flashlight (May 13, 2009)

Can't say that I've had much experience at looking into the eye of a true lightstorm, but many of us are Thefirstthingyoudoislookintothebeamophiles, and even with lower output lights that might not be very wise in the long run. Haven't heard of any studies of this, but maybe a search of the forum might turn something up.


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## ruriimasu (May 13, 2009)

i stared into my LF2x at max brightness about 5secs at less than 2ft. then saw a "burnt" mark on anything i laid my eye on for the next 10mins.. so my advise.. dont try! :shakehead


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## DoctaDink (May 13, 2009)

From personal experience I can tell you that a photo strobe can cause permanent retinal damage (Foveomacular retinitis). As a teenager, I (foolishly) repeatedly flashed a strobe in my eye and ended up with a permanent deficit in the central vision of my right eye. I would think that a LED flashlight would be much less likely to cause damage, but I wouldn't test it! I can attest that it is a drag to lose visual acuity;especially in your dominant eye.


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## matrixshaman (May 13, 2009)

You've only got two of them - don't take chances. It will depend partly on your age also. I've had after images of a couple lights (not that bright either) stay with me a couple days. I can't think of any good reason to stare at a bright flashlight - it's focused and a lot closer than that light bulb on the ceiling. Just don't do it. Keep you lights pointed away from eyes - yours and other peoples - especially at close range.


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## Cataract (May 13, 2009)

The amount of UV an LED can give off is surprising! Just tested it out with a calibrated Radiometer at 320 to 400nM frequency (UV-A)... 

My terralux 140 Lumen comes close to 900 uW/cm sq (microWatts per centimeter squared) at point blank

my Fenix LOD comes close to 120 uW/cm sq point blank

TK 40 on turbo: about 710 uW/cm sq point blank (the terralux is bluer in comparison and TK 40 has wider beam)

these all diminish dramatically with the distance. At 15 inches, the TK40 is about 150 uW/cm sq, Terralux 20-30, LOD = nothing

A regular black light is likely less than 1500 uW/cm sq... don't have one to test, but I can say that military specs for fluorescent inspection specify 1000 - 1500 uW/cm sq on the work surface, which comes from a mercury lamp and I can tell you that having one of those around is hard on the eyes, you can feel the fatigue, but these lamps give off a very specific frequency compared to.
I don't think any of those give off any UV-B, or you could use it to get a tan and probably would need a generator to run them.

As a reference, the sun is high up and I got close to 6000 uW/cm sq on the meter (UV-a only). I think your eyes can withstand that for less than a minute without permanent damage, and that does include more harmful UV-B and UV-C. The inspection lamp give out more than that at closer than 10 inches.

I did a stupid test yesterday (gotta do some stupid stuff when you get a new light! :thumbsup: ) I usually test my new lights by closing my eyes and shining them in my face at arms reach, just to get an idea, but this time I kinda "flashed" my eyes open... boy that hurt real bad! :duh2: My eyes where watery for over an hour. :mecry:I tried the same with the sun, knowing that less than a second isn't supposed to damage (otherwise we'd all be blind by age 5) and it hurt less... 

Conclusion: I don't really think the UV from a flashlight is sufficient to do permanent damage under a minute, but you should ask an eye doctor to know what we can really endure.


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## csshih (May 15, 2009)

interesting, cataract 

do you have any access to blue leds or actual UV leds for testing?


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## LukeA (May 16, 2009)

Cataract said:


> The amount of UV an LED can give off is surprising! Just tested it out with a calibrated Radiometer at 320 to 400nM frequency (UV-A)...
> 
> My terralux 140 Lumen comes close to 900 uW/cm sq (microWatts per centimeter squared) at point blank
> 
> ...



That's what, 1/1400 as much energy as is radiated as visible light? That's not really worth too much worry, IMO.


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## Leo (May 16, 2009)

Cataract said:


> The amount of UV an LED can give off is surprising! Just tested it out with a calibrated Radiometer at 320 to 400nM frequency (UV-A)...



I didn't know that, but it sure explains a lot. I'm more sensitive to light than most, and LED flashlights give me symptoms that match those of UV exposure, called arc eye, which is commonly caused by welding without proper protection. The symptoms feel like having little grains of sand in your eyes, and last a day or two.


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## Juggernaut (May 16, 2009)

I know one thing far sure, it doesn’t matter how much UV is coming out of a light: if it’s a hotwire and can set things on fire / it can set your face on fire and that would mean your eyes would be on fire and I bet if your eyes are on fire, they are going to get damaged but that’s just my theory.


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## Guy's Dropper (May 16, 2009)

Both UV and IR light can do serious dmage to your eyes. IR light is emitted by all incandescent lights and some. UV is emitted by most LED. I don't see the point of this question though. Why would you wan to look into a light if bothers your eyes at all? Here's some common sense advice: Don't stare directly into a light!


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## Cataract (May 21, 2009)

csshih said:


> interesting, cataract
> 
> do you have any access to blue leds or actual UV leds for testing?


 
I guess I should test my multicolor flashlight, (10 color mix using red/green/blue) but I don't have a UV light... I could get my hands on an inspection UV flashlight, but those are military-grade and cost a bundle... and by nno means represent what you can get from regular stores...


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## aMonster (Mar 6, 2010)

I was just looking for information on this very problem because two weeks ago I got beamed in the right eye by a cheap 5 led flashlight bought at a dollar store and I still see a burn mark where the flashlight got me.

I was hoping this was going to clear up but it hasn't and I've already been to see an ophthalmologist, he said he couldn't believe an LED flashlight could burn a retina and I'm hoping he's right but still, two weeks later I still have this burn mark in my right eye vision.

The ophthalmologist is having me back next week to do another test as he wants to try and confirm what has happened but, if it is a burn to the retina there is no cure.

I'd love for someone else to tell me this has happened to them and that eventually, the dark spot cleared up for them. To say the least I am extremely upset about this as I had absolutely perfect vision at age 39 years old and now, I have my doubts this problem will solve itself.

I know people will want to know how it happened and for how long so, here it is. I was working inside a computer server case and set this small LED flashlight on one of the CDRom drive trays, I then stuck my head into case to work on replacing a chasis fan. At one point I tilted the server case back and the flashlight rolled to the other side of the ledge it was resting on, the blast I took in the right eye only lasted for about a full second at a distance of like, 12 inches.

As surprising as this is it has happened so, I say to all of you... be very very careful please... and if anyone else has experienced this I'd sure love to hear back from you, hopefully with good news about how it eventually cleared up.


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## Benson (Mar 6, 2010)

Cataract said:


> I did a stupid test yesterday (gotta do some stupid stuff when you get a new light! :thumbsup: ) I usually test my new lights by closing my eyes and shining them in my face at arms reach, just to get an idea, but this time I kinda "flashed" my eyes open... boy that hurt real bad! :duh2: My eyes where watery for over an hour. :mecry:I tried the same with the sun, knowing that less than a second isn't supposed to damage (otherwise we'd all be blind by age 5) and it hurt less...


Suggestion: if, for whatever reason, anyone wishes to deliberately give themselves a brief open-eye flash, it seems that starting with your eye open and flipping the light on would let your blink reflex actuate quicker than when you're forcing your eyes open on an already-shining light. But IANAbiogeek of any sort, just seems logical.

Since we're swapping stories of stupidity, the other day I hit myself in the eye with a CSM-360 LED at ~25W in a Mag reflector, from about 8 inches away. (Yes, it was an accidental discharge -- I don't intentionally fire that bad boy up when I'm anywhere in the forward hemisphere!) Honestly couldn't see a thing with that eye for 5 seconds, and it actually _hurt_ after the light stopped, unlike any other light I've nailed myself with. So I'm thinking I'll dig out my sunglasses before the next round of CSMarnage.



Monster, I can't say I've ever had spots on my eye last more than a couple hours, sorry. It's crazy how bright those 5mm LED lights can appear because of the small emitting area, but I wouldn't have expected any possibility of lasting damage either. If it's been 2 weeks, I'd imagine it's permanent damage. However, your brain will adapt and interpolate/filter as needed, so the visible "stain" will eventually fade.


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## Swedpat (Mar 7, 2010)

Sometimes ignorant people as a practical joke demonstrate the brightness of a flashlight by shining in peoples face at close distance. Such stupidness makes me irritated. I guess shining a bright flashlight in the eyes at short distance may be harmful for the eyes, especially when eyes are a bit dark-adapted. At short distance the hotspot of a flashlight surely can be brighter than direct sunlight.


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## don.gwapo (Mar 8, 2010)

Just don't look directly on the light or point it on somebody else as simple as that. That's why you see a warning sign on the head of most lights.


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## Zippoman (Mar 8, 2010)

*630 lumens in eyes??*

what would a 630 lumen flashlight do if i looked into it would it damage my eyes?


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## LightJaguar (Mar 8, 2010)

*Re: 630 lumens in eyes??*

It would hurt. Don't be shining flashlights into your eyes is not a good idea.


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## jhc37013 (Mar 8, 2010)

*Re: 630 lumens in eyes??*

You could have just asked in your other active "which brand to buy" thread but it would hurt I wouldn't recommend it.


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## DM51 (Mar 8, 2010)

*Re: 630 lumens in eyes??*

Your natural reflex action when dazzled by a bright light will be to blink your eyes shut and turn away from it. The blink reflex will be quick enough to prevent damage. However, it should be obvious that if you force yourself to override the reflex and stare at a bright light for long enough, you will eventually damage your eyes.


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## Fusion_m8 (Mar 8, 2010)

*Re: 630 lumens in eyes??*

Shouldn't this topic be in the general flashlight discussion forum merged with this other thread???


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## DM51 (Mar 8, 2010)

*Re: 630 lumens in eyes??*

Yes - thanks for the suggestion. Merging them now.


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## joshconsulting (Mar 8, 2010)

*Re: 630 lumens in eyes??*

First, you'll experience a bright flare of light. As others mentioned, reflexes will kick in and you'll drop your head and shut your eyes, but it's a little late. For the next 5 minutes, you won't be able to see much of anything due to the large purple blob in the center of your vision. It will slowly go away over a period of 1-1.5 hours. About 20 minutes in, the headache will start, and won't subside for at least 3-4 hours. Beyond that, your eyes will be sore for as much as 36 hours.

Yea, I had to try it with my DBS SST-50 once. Don't do it. I was overly curious. Your eyes are much too valuable to risk in such a dumb manner :shakehead


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## Swedpat (Mar 8, 2010)

*Re: 630 lumens in eyes??*



Zippoman said:


> what would a 630 lumen flashlight do if i looked into it would it damage my eyes?



Very much depends on the max light intensity a flashlight produces. A 260lumen thrower like Tiablo A10 can be more harmful than Fenix TK30/40 with 630lumens. This because the A10 puts out more than twice the lux in the hotspot than TK30/40. Another example is if you compare with a 100W home light bulb. Such one puts out ca 1300lumens but will still not be harmful for the eyes because it's floodlight and the lux is still low compared to the hotspot of a dim flashlight.

Regards, Patric


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## Apollo Cree (Mar 8, 2010)

Do you have a flashlight that's brighter than the noon sun? 

If you are outside, and look up at something that is blocking the sun, and it moves exposing the sun, do you damage your vision? If a mirror or other reflective surface suddenly bounces a sunbeam into your eyes, do you get eye damage? 

Yes, temporary spots, pain, etc., but have you ever gotten eye damage from a temporary flash of sunlight unless you made a point of staring at it? 

I don't see how you're going to damage your vision unless you suppress your blink reflex and deliberately stare into the light. If the sun doesn't damage your eyes from a brief exposure, why would a flashlight? 

Maybe there is some reason why a flashlight would damage you when the sun won't, but I don't see it. 

However, I do agree to not flash someone in the eye unexpectedly. If nothing else, they might respond by hitting you with something more solid than photons.


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## Dude Dudeson (Mar 8, 2010)

Apollo Cree said:


> Do you have a flashlight that's brighter than the noon sun?


 
As a matter of fact, yes.

I just took my 6P/M-60 outside and shined it on the driveway. Couldn't see the beam at all from standing height, pointed straight down.

But as soon as I got the light within about 2 feet of the ground the hotspot materialized. At about 18 inches there was no doubt about it, that hotspot was brighter than the sunlight.

So yes, if you flashed someone with this thing within 18 inches of their face it's going to be brighter than the sun.


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## Fusion_m8 (Mar 9, 2010)

Just curious as to the difference permanent damage to the eyes when exposed to say a 700 lumen Jetbeam M1X and the 5mW Laser from a Surefire X400, both for at least 10secs continuous?? 

Wouldn't the 700lumen Jetbeam pose a more serious threat to permanent blindness than the 5mW Laser?? If not, why?


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## choombak (Mar 9, 2010)

I had the Arc-AAA shine in my eye by accident - hardly a second or so, and I got my head spinning after that for full 15 minutes. Experienced the same thing with a Peak Matterhorn 3-LED one too.

So I'd say, don't do it. Whether damage occurs or not, the spinning head feeling is way too bad for that second of exposure. :-/

Plus, if you lose vision, how would you judge the beam and spill of flashlights in the future? 

-Amarendra


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## dieselducy (Jun 24, 2010)

I have a royal blue lite in a surefire 6b it is a luexon rebel. i have stared into the led before. is this dangerous at the color of 447nm? the lite coming out of the flashlight is hot i can feel heat from the hotspot when i shine it on myself..


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## Let It Bleed (Jun 24, 2010)

What a long strange trip it's been.


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## ccclove499 (Jun 10, 2011)

jeffreyliu838 said:


> How many lumens does it take to damage the eye? Will direct exposure to 300 lumens do any damage within like 2 minutes?
> 
> Thanks.


 
ABSOLUTELY! 2 minutes is more than enough time to damage your eyes for life. 300 lumens can cause a hotspot and can burn holes even if you don't notice. Be smart!
The good news is that all you need is a covering over your eye, even if it is just a pair of wholesale sunglasses. That is what I was recommended when I asked the same question a couple years back. I learned that some people are more sensitive to light and would know right away if their eyes were being burned, others wouldn't know until their eyes were ruined. Always be wise and cover your eyes!


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## Cataract (Jun 10, 2011)

*Re: 630 lumens in eyes??*

I have done the testing for you, right here. Intense strobes in the face intermittently for about an hour at less than 10 feet distance and no problem here, set aside the fact that our eyes did hurt a little for a couple of days. I am surprised you still see that burn mark. IMO regular visible light should not damage the eyes but UV can. If you read my older posts from before the thread revival, I commented about the fact that LEDs do emit some UV. The question is how much, at what frequency (nm) and for how long does it start to be a problem.

I've had multiple close encounters with fallen flashlights and a clumsy cousin who probably shone himself in the face more than I ever did that to myself. I've had people turn on my Malkoff MC-E (400 lumens) right into their faces and no one complained of eye damage. 

I really hope that spot goes away for you.


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## sjmack (Jun 11, 2011)

GreyShark said:


> ... The sun is cranking out, oh, I don't know, one hundred quadzillion to the third freak'n power mega-lumens(but is that bulb or torch lumens?)...


 
How many zeroes would that be?


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## Kingfisher (Jun 11, 2011)

jeffreyliu838 said:


> How many lumens does it take to damage the eye? Will direct exposure to 300 lumens do any damage within like 2 minutes?
> 
> Thanks.



Yes, I think so.


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## xxzoe85xx (Nov 17, 2011)

Hi, I have a teeth whitening high intensity LED that i have just bought from China, when I have used it even though i have had red glasses on, i noticed a bit of a headache and the day after my eyes seem a bit fuzzy not anything major almost like i was looking through glass that hasnt been cleaned in a while, do you think this is anything to do with the light or just some other reason...the light is supposedly 450-495 nm wavelength and 6000 mw/cm2 intensity. Thankyou


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## fyrstormer (Nov 17, 2011)

That sounds like a UV light, xxz. The rating isn't UV, but I bet it produces a lot of UV light anyway. UV will definitely cause eye damage. If you're going to use it, wear an eye mask.


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## fyrstormer (Nov 17, 2011)

Regarding eye damage from white light: look, if it hurts, it's doing damage. That's why it hurts. It's not complicated.


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## Acid87 (Nov 17, 2011)

fyrstormer said:


> Regarding eye damage from white light: look, if it hurts, it's doing damage. That's why it hurts. It's not complicated.



Love it +1


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## mikedeason (Nov 17, 2011)

yes I get people complaining about my TK35 when walking the dogs and I am very careful.

Wondering if the government may indroduce legislation to limit lumens if it gets to a point where people can buy a 2000 lumen light at Wal Mart for $30


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## Jash (Nov 17, 2011)

*Re: 630 lumens in eyes??*

For those that do wish to look into their lights at arms length, cough *Cataract* cough, I suggest looking at them some welding goggles or similar. This is what I do to impress myself on how bright my lights are if they can shine a dim green light on the wall through me welding goggles.

Also, you get to gaze straight into those beautiful emitters and be awed be the physics going on inside that metal tube.


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## MikeAusC (Nov 18, 2011)

If you have a look at Cree Datasheets, modern White LEDs put out very little of their energy in the UV range (<400nm). 

In the Infrared range (>700nm) the energy is quite high, especially for Warm Whites.


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## richpalm (Nov 18, 2011)

mikedeason said:


> Wondering if the government may indroduce legislation to limit lumens if it gets to a point where people can buy a 2000 lumen light at Wal Mart for $30



Oh, that's coming, I'm sure.

Rich


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## beerwax (Nov 18, 2011)

fyrstormer said:


> Regarding eye damage from white light: look, if it hurts, it's doing damage. That's why it hurts. It's not complicated.


 
yes maybe but also just because it doesnt hurt doesnt mean it is not doing damage.


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## vatrainer (Aug 21, 2012)

I would really like to know the answer as my job and those I teach jobs require us to shine bright lights into peoples eyes. 

I found the following at http://www.pullmaneyedoctor.com/articles/1922-bright-light-and-your-eyes and thought it might be helpful to the discussion.


eyedoctor said:


> "If peered at long enough a bright light can cause damage to the nerve tissue layer that forms the inside lining of the back wall of the eye. This clear layer is known as the *retina*. It’s what stands between us and blindness. The human eye concentrates light and heat about the same as a 40 power magnifying glass. Most of the time too much light simply makes the retina edematous, or it swells. This may cause things to look blurry or distorted. Usually in a few days the edema recedes, and the vision returns to normal.
> The most common source of light causing this kind of vision problem eye is the sun. The condition is called *solar retinopathy*, ..... If a sun gazer looks for a short time the damage resolves. If it is too long the damage is permanent.
> How long is too long? A second or less can make a difference. It's better to never look at the sun under any circumstances.".



He goes on to talk about eclipses and such you know......SUN is bright, fire hot, don't look at an eclipse then:



eyedoctor said:


> "There are some other types of light sources that are known to cause solar retinopathy, but the damage is *rarely permanent*.
> Another problem that sometimes happens with light and the eyes is with excessive ultraviolet (UV) exposure. This is sometimes called *welders burn* because the UV from an arc welder damages the surface of the little clear dome on the front of the eye (cornea).
> This is commonly caused by welders, but it can also be caused by to much sun exposure especially when reflected off the snow (_*snow blindness*_) or by UV lights sometimes found in laboratories. UV burns are seldom serious and people usually recover after a few hours or within a day, although the discomfort during the healing time can be almost intolerable. *Oral narcotics *may be necessary.
> 
> Dan David, O.D. "




I also found a related topic on Discovery.com http://curiosity.discovery.com/question/how-intense-light-damage-eyes. 

All pain does not cause injury not all injury causes pain. Pain is usually a nervous response to an impulse outside of the nerves parameters, granted a lot of the time it is from some form of damage. However saying if it causes pain then it is causing damage is a bit of oversimplification. Otherwise children would be losing brain cells right and left from slushies,(note: that might actually explain Justin Bieber).


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## fyrstormer (Aug 23, 2012)

vatrainer, a good rule is one which has a *few* notable exceptions. The rule "if it hurts, it's causing damage" follows that paradigm. Vigorous exercise is a notable exception; while it does cause damage, the rebuilt muscles and tendons are stronger than they were before. Smoking is another notable exception -- it doesn't hurt (much), but it causes damage anyway. Cold-headaches _might_ be a notable exception, though it does indicate localized hypothermia, which is worth avoiding regardless of the potential for frostbite.

Bright light is _not_ a notable exception to the rule that pain indicates damage. The light-sensors inside rod cells are consumed in the process of sensing light, and extremely bright light can burn-out all the sensors inside the cells after just a few seconds, requiring several days to recover fully. This may be the underlying cause of retinal edema, I don't know for sure, but even if it's a totally separate effect from any longer-lasting retinal damage, it's still worth avoiding. So as I said before, "that's why it hurts. It's not complicated."


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## She Rides On Moonlight (Jan 14, 2014)

I was reading to my 7 yr. old daughter when my cell rang. When I turned to grab the phone she grabbed my magnifying glass and looked through it straight into a Feit 130 volt/60 watt IO7 lightbulb. I don't know for how long. She says about 3 seconds. Tears were pouring down her face uncontrollably but she wasn't crying. She was smiling and I was about 20 guesses in before she finally told me why her eyes were "crying". They started to pink and the flood of tears continued for several minutes but she said they didn't hurt. Now they do and they're getting really red. I put my sunglasses on her and told her to lie down and keep her eyes closed until I figure out what to do. It's night or I'd have her at the eye doctor already. Should I take her to the ER? Do you think there's anything they can do to save her eyes from further damage, if they are in fact damaged, or going blind. Oh my God. Could something like this cause her to go blind gradually? She says there are not spots in her vision and its not blurred. She insists they don't hurt "not much" but I think she's just trying to act brave because she keep her blanket over her head with the sunglasses on at night. I don't know what to do. That's why I'm reaching out to you. Anybody. Anybody out there. I'm alone. I'm scared for my baby bunny boo. I don't know what to do....


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## jonwkng (Jan 14, 2014)

Sorry to hear about what happened. She needs an Ophthalmologist consult. Get her to the ER if you don't have access to an Ophthalmologist. Her eyes will need further assessment ASAP.


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## Etsu (Jan 14, 2014)

Not much the ER can do. Take her to the eye-doctor in the morning, if she's still seeing spots. Probably nothing to worry about. Kids do stupid things but they seldom do damage. Pain is pretty good at preventing us from going too far. Baby bunny boo???


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## BillSWPA (Jan 14, 2014)

Etsu said:


> Not much the ER can do. Take her to the eye-doctor in the morning, if she's still seeing spots. Probably nothing to worry about. Kids do stupid things but they seldom do damage. Pain is pretty good at preventing us from going too far. Baby bunny boo???



This is most likely correct. Whem my wife went to a local ER for an eye injury (our son had accidently poked her in the eye, causing a few layers of cornea to tear off, and prior lasik surgery had weakened the cornea), they were absolutely no help. She was seen by a physician's assistant, given medication that did nothing to help and increased her discomfort, and told to see her eye doctor in the morning. If you ever have to go to the ER for an eye injory, make sure the hospital you pick has an eye doctor on call before you go.


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## Etsu (Jan 14, 2014)

Let's be realistic here. She looked into a 60w globe lightbulb for a few seconds. Yes, it was with a magnifying glass, but that would be the same effect as simply looking at the bulb at a much closer distance. Is that likely to cause any permanent damage? No, not likely, the lux is simply too low. The child says she isn't seeing spots or is in any pain. That's a pretty good indication she's fine. Eye's don't get red/pink from looking at a light. They get red/pink from crying, which is exactly what she was doing, probably made worse because she's being scared by a parent who has her hiding under a blanket wearing dark glasses in the middle of the night. Parents need to calm down and not over-react. Wasting medical resources on an ER visit won't help anyone.


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## boki (Jan 14, 2014)

I hope she is doing fine - what did the eye doctor say?


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## Cataract (Jan 25, 2014)

As far a I can tell, and I have done a lot of stupid things and research on this, it would seem that only UV light can actually damage the eyes. I have even read multiple comments of people asking their ophthalmologist about this type of stuff and one clearly said that he couldn't see how one could get permanent eye damage from looking at a bright light. 

UV is a different story and should be avoided as much as practical -the sun hasn't blinded anyone going outside unless they did something unusual and stared at it like crazy (and then some) or through some lens. Welding can cause a lot of UV flashes and it's a generally known fact that it is bad to look at weld flashes. Not too many welders complain about the fact that they have to wear really dark goggles, but it still seems like a lot of exposure(s) is needed for noticeable damage to take place. Even bad exposure, such as welder's flash only affects the outer layer of the eye and can heal within days. 

Still, the eyes are important and, when in doubt, always consult...


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## mercanucaribe (May 6, 2015)

Cataract said:


> As far a I can tell, and I have done a lot of stupid things and research on this, it would seem that only UV light can actually damage the eyes. I have even read multiple comments of people asking their ophthalmologist about this type of stuff and one clearly said that he couldn't see how one could get permanent eye damage from looking at a bright light.
> 
> UV is a different story and should be avoided as much as practical -the sun hasn't blinded anyone going outside unless they did something unusual and stared at it like crazy (and then some) or through some lens. Welding can cause a lot of UV flashes and it's a generally known fact that it is bad to look at weld flashes. Not too many welders complain about the fact that they have to wear really dark goggles, but it still seems like a lot of exposure(s) is needed for noticeable damage to take place. Even bad exposure, such as welder's flash only affects the outer layer of the eye and can heal within days.
> 
> Still, the eyes are important and, when in doubt, always consult...



This is false and I have no idea why people keep repeating it. Visible light can damage the retina. Why do you think looking into a laser beam is bad? Why do you think looking at the sun is bad even with UV blocking sunglasses? There are MANY scholarly articles on this topic. http://www.ncbi.nlm.nih.gov/pubmed/22085795 http://www.photobiology.info/Rozanowska.html


There are two mechanisms of damage. One is physical heating of the retina, which happens when you look at the sun for a few seconds. It burns the retina and leaves a scar. The other method is photochemical, which can happen with dimmer light sources over longer periods. The visual chemicals are what do the damage in those cases.

What matters is NOT the total lumens of the light source. It's the intensity of the light focused on your retina. An LED flashlight is more dangerous than an incandescent one with the same lumens, because with the LED your retina recieves an image of the emitter which is the sole light source. With an incandescent flashlight the bulb is emitting light in all directions and relies on a reflector to focus it, so the image on the retina is the size of the bulb plus the reflector, hence less intensity.

These high lumen flashlights have LED emitters that are brighter than the sun. So to assume they won't do damage to the retina is just plain dumb. BTW there is a simple way you can prove this. With your high powered flashlight turned off and batteries out just in case, hold up the flashlight in front of you and move it to a distance where the yellow square of the emitter looks as big as the full moon. The moon appears as big as the sun to us (0.5 degree). Remember that distance. Now put the batteries back in and point the light at a wall from that same distance and turn it on. The lux (intensity) is at least as bright as direct sun, with the apparent source the same size as the sun. You can measure it with a light meter or cell phone app.

The other thing is that distance doesn't matter except regarding your eye's ability to look away quickly. The intensity is the same, only the apparent size of the light source projected on your retina changes. If you move the light 2x as far from you, 1/4 the light reaches your eye but the emitter appears 1/4 as big, so intensity is just as high and so just as dangerous.

Edit: More info http://www.ledsmagazine.com/articles/2005/06/leds-are-safe-fact-or-fiction.html


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## Phlogiston (May 12, 2015)

I try not to write too many "me too" posts, but this one is important enough to bear repetition. 

*Do not ever look into a laser beam, a flashlight beam or directly at the sun.* 

*Do not ever shine a laser beam or a flashlight beam into someone else's eyes.* 

*Collimation*

As we all know, a visible light laser will damage your retina if you look into the beam. There is no infrared or ultraviolet content in a visible light laser, so it follows that visible light can and will damage your retina if it's too intense. 

A laser beam is collimated, which means that the photons are all moving in exactly the same direction, in parallel, with no divergence. Collimated beams focus to a point, which is why five milliwatts of laser light is enough to do damage - the entire five milliwatts is focused on a handful of microscopic cells in your retina, which will promptly die and leave you with a tiny but permanent black dot in your visual field. There's no treatment for this type of retinal damage. 

Most flashlights have some sort of focusing arrangement, be it a reflector, lens or TIR optic. The beam isn't collimated, but most of the light is going in more or less the same direction, so it can get pretty close. 

Throwy flashlights are the worst, since they have to get very close to collimating their beams to achieve a high intensity of light at long distances. However, most flashlights will create a high enough intensity - especially at short range - to put your retina at risk. 

Even a cheap SK68 clone can put your eyesight at serious risk - when you zoom it right in, so it projects an image of the LED die, you're creating a near-collimated beam. 

*Point Sources* 

If anyone here is thinking, "oh, that means my bare-LED mule light is safe," think again. Point sources also focus to a point, even if they're radiating light omnidirectionally, because the photons that do reach your eye are coming in on near-parallel tracks. If the point source is radiating enough light in total, the fraction that reaches your eyes and gets focused on your retina will do damage. 

That's in spite of the fact that most of the light goes in other directions entirely, so that the fraction which does reach your eyes will be drastically reduced by the inverse-square law. 

This is why the sun is dangerous to your eyes. At half a degree of apparent angular width, it's not quite a point source, but it comes pretty close, and it puts out enough energy - even at an immense distance from the Earth - to overcome the angular spread and the inverse-square law to do damage anyway. 

In a similar vein, looking at a bright LED at short range can do damage, even without any sort of focusing arrangement whatsoever. You're a lot less likely to hit the conditions in question, but the possibility still exists. Don't just assume it's safe. 

An LED is usually more intense and therefore closer to a point source than an incandescent bulb of the same light output - the filament tends to physically take up more space - but it doesn't actually matter how you get the light. You can do damage with LED, laser, incandescent or arc-based light sources, for example. The incandescent may be "safer" under otherwise identical conditions, but that's not the same as "totally safe". 

In theory, even a light with a diffuser on the front could be a problem, if it's bright enough. Perfectly safe under the vast majority of conditions, but there's still that corner case of very high brightness at very close range. 

*Infrared Light* 

Near-infrared light - wavelengths which are close to deep red, but not quite visible - will be focused onto the retina by the lens of the human eye. This means that near-infrared light can do damage by the same mechanisms I describe above. 

Far-infrared light - wavelengths which register as heat - will not pass through the lens. It just makes the surface of your eye warm, which will only do damage if it gets hot enough to burn. 

*Ultraviolet Light* 

The cornea of the human eye blocks ultraviolet light by absorbing it, so only a small percentage of incoming ultraviolet light can reach your retina, and most of it will be at near-ultraviolet wavelengths close to violet but not quite visible. 

This can still be focused and do damage if there's enough of it, but the usual mechanism of ultraviolet damage is different. 

As the cornea blocks ultraviolet light by absorbing it, not reflecting it, the energy from those ultraviolet photons has to go somewhere. Unfortunately, it goes into disrupting the proteins of the cornea and the cells which maintain it. 

Among other things, the disrupted proteins no longer transmit light and become visible as a milky effect. This is the effect that underlies cataracts. In mild cases, the eye will repair itself, but severe damage will result in full-blown cataracts and permanent blindness. The only cure for that is a corneal transplant. 

Don't mess with your eyes. They're too important for that.


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## MidnightDistortions (May 14, 2015)

I have pretty good reflexes when it comes to 'too bright' beams being shoved into my eyes. I had a lot of pictures taken with the flash and often times you'll get the spots for 10 minutes and it goes away. So right away if someone were to shine a light into my eyes i would be seeing similar spots for 10 minutes or so but why would you do this deliberately for 2 minutes? It's kinda like when the doctor shines his penlight in your eyes to check the responses, it's only for a few seconds, he's not sitting there for several minutes with it because he knows it would cause pain or problems. If you are seeing the flashlight spot longer than a few hours i would definitely see a doctor about it, but i wonder if some people take longer to adjust or to heal from the bright light. If the light is too bright your reflexes should kick in or at the very least you would experience temporary blindness. Of course when i am getting my picture taken i'm already aware of it so my reflexes are ready for the flashes and i either look away or my eyes close when the flash happens (sometimes messing up the pictures lol). My eyes do appear to be sensitive towards bright lights so i think that helps.

Some people will end up staring into a light before turning it on temporarily blinding themselves and even if you are not looking directly into the light it can still cause you to be temporarily blinded if it's on your eyes. It would be best to avoid this all together if you intend to keep your vision at old age.


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## RetroTechie (May 14, 2015)

mercanucaribe said:


> What matters is NOT the total lumens of the light source. It's the intensity of the light focused on your retina.


Amazing the background lighting conditions haven't even been mentioned in this thread, with postings over several years... 

When you're out in the sun, overall high illumination levels make your eye's iris contract, so your pupil becomes very small. The back of your eye receives well focussed images, but only a small % of light that hits your eye, makes it to the light-sensitive back/inside (retina). And thus you'll need a very high intensity light source (sun-like lux values) to have a chance of damaging the retina.

When you're inside a house late at night, overall illumination is much lower, and your pupil is much wider. Images are less focussed, but a much higher % of light that hits your eyes, passes through onto the retina. For a high intensity light source like a flashlight beam, it's much easier to do damage then.

So it's not just intensity, but also what your eye is adjusted to. Read: how that intensity compares with background illumination levels. Shine a flashlight beam directly into your eye, and you'll have high lux levels at the surface of the eye - *while it's still adjusted to much lower lux levels.* Only a fool would think this has no potential to cause damage...


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