Eye damage?

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

Thanks.

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

Avoid UV lights they cause cataracts.

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.

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.

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.

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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).

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).

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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.

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.

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.

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.

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

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.

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.

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.

interesting, cataract

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

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

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)

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

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)...

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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.

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!

csshih said:

interesting, cataract

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

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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...