Flashlight safety?

You know, ever since I bought my REAL flashlight a couple years ago (Inova T1, 100 lumen) I have been MORE than impressed at what technology has offered and continues to offer with modern improvements.

We all have done it...blasted someone, even with a quick blink on a tactical tail switch, and given them a big old eye spot for a couple minutes. We laugh about it and go on our way.

My question is, since our kids often get the brunt of my screwing around (and friends at camp outs and parties), how bright is too dangerous for our eyes to handle? Are modern 2xCR123 flashlights too bright on "turbo" mode? Obviously, some retard isn't going to stay there and keep their eyes open for the abuse, so it is a momentary blip they get, but I got to wondering about this today.

It has to do with how close the photons are, not necessarily how many there are - lasers are what you have to worry about, not flashlights.

Good question, not only because of our kids, but our own stupidity/ curiosity. Just yesterday I wondered if the 65 lumen of my SF6PD could become unpleasant at arms length during dusk. :duh2:

Or shining a bright light indoors to close to the wall.

Cheers
Thorsten

StarHalo said:

It has to do with how close the photons are

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Don't all photons have the same distance to your retina when you see em?

I might be wrong, but I believe it would come to down to lux, not lumens. A highly concentrated beam of 100 lumens will be much harder on your eyes than 200 lumens of pure flood.

I'm not a doctor and I don't play one on TV but I always reflect on the fact that it is possible to glance at the sun with no permanent eye damage. Or at least it's happend to me about 1000 times over the years and I can still see. The eye has mechanisms, like blinking and head turning, that protect it from even such damaging exposure and I can't imagine that a mere flashlight could cause any permanent harm. Certainly there have to be about a million officers and soldiers who have personally tested out the "tactical" use and limits of current lights and they all seem to be OK. Lasers now, that can actually burn through the retina- nature isn't prepared for that. Still it never seems to happen.

RepProdigious said:

Don't all photons have the same distance to your retina when you see em?

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To each other, silly

For eye damage, you generally have to have a large number of photons per square millimeter on the retina. If I recall from my last time researching for one of these threads, the eye's lens focuses light that hits it onto the retina. At a low level of light, the eye's chemical reactions are saturated and the 'seeing' bits get fatigued for a while. That seems to cause the green spots from staring at bright things. This seems to be harmless.

The human blink reflex isn't evenly triggered by all frequencies. We tend to blink more slowly at a given intensity of blue light than any other color, or white light. And white light sources with large blue components trigger the blink reflex a bit more slowly than white light. But for an LED to cause damage before the blink reflex hits would be a bit nuts. I don't have exact numbers, but you could run lux numbers and find out that today's technology couldn't do it by accident...yet. One CPF member had lasting effects from a short light blast, so he went to an eye doctor. That often indicates a different problem that the light revealed. So...lights are good for your eyes?

At higher intensity levels, the photons heat the retina enough to damage it. If you've seen pictures of a retina with little round marks, you've seen this damage (or early retinal detachment?). Generally, only lasers reach this level. If I have a 100mW laser beam, 3 mm across, hitting my eye, most of its energy will go into my pupil. The lens in my eye will dutifully focus the laser beam so that it concentrates onto a small part of my retina. If I was focusing on the aperture, it'd be a very tiny point. For a flashlight to reach this light level would require some ridiculous amount of power.

At enough power, the laser will basically blast some of your retina to steam. This is 'acoustic' damage, and some people in labs have heard the *pop!* inside their own eye sockets. This generally destroys the whole retina. Don't play with lasers! Lights probably won't cause permanent damage, but they're no toys either. Treat 'em all like a gun.

It all depends, I would be inclined to believe though that a blast from a Mag85 or a surefire Hellfighter at close to point blank range could do some serious damage.

Hello, I'm new here but being in the medical profession we shine bright lights in our patients eyes often. It's never fun for them but not harmful with our equipment. In staying that I would like to know, like the op, at what brightness or "power" will cause damage to the eye. I've seen vids of a large light called the Wicked Laser or something, it seems to quickly burn paper like a lighter and burns holes in objects. I could only think what damage it would do to your eyes or even just your hand if the user is careless. I think this light is advertised as around 8100 lumens. Any thoughts?

I can see the new warning labels on flashlight packages now...

WARNING! This product has photons known to the state of California to cause cancer and reproductive harm.

TwinBlade said:

WARNING! This product has photons known to the state of California to cause cancer and reproductive harm.

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why would anyone want to live in california, almost everything causes cancer there, lol.

on the serious note, i can't recall how many times i got flashed with photo flash in my eyes when i was a kid, it was a game we played, has anyone tried magnesium shavings and kmno4?? brightest flash only made by nuke explosion, we used to build flash bangs like that when we were kids all the time, and i did have mag 85 beam hit me in the eye from a foot or so away, so did p7, 3xp7, and 150w halogen, i had spots in my eyes, temp. but despite all that still have 20\20, no dark spots permanently. even thou no perm damage done, i still wouldn't recommend to repeat that.

lasers are another story, even with eyelid closed it still can create uncomfortable feeling for a while, i know.
this weekend, i was camping, i was in the tent, and someone just moved green laser across our site, and across my tent, holly s..t, it was bright, even inside the tent laser beam was still visible, i found him, the dude had no idea who he started with, i too had my 50mw laser in my lantern, along with my 3xp7 and 90w halogen, let just say i found few ppl willing to pay good money for me building them the same lanterns, looks like i'll be busy.

I've always wondered this as well. Nearly all of my guns are equipped with weapon lights, and before mounting them, I've always given myself or a reluctant volunteer a blast of light at semi close range just to test them out. Now most of the lights are around the 120 lumens mark, so nothing extreme, but I'm still curious if there is any temporary or permanent damage (no matter how small) occurs.

StarHalo said:

It has to do with how close the photons are, not necessarily how many there are - lasers are what you have to worry about, not flashlights.

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Shine an HID in your eyes and I guarantee you will change your tune. Lasers are not inherently dangerous, and many have lower energy densities than very bright lights. LED technology is at the point where close eye exposure can cause permanent damage or at least temporary inflammation/blurriness.

I don't know if it is true or not, I bet someone here knows. I seem to recall reading somewhere that a high power infer red red flashlight can cause permanent eye damage without causing you to blink, or even knowing you are looking into a light

divechief said:

I don't know if it is true or not, I bet someone here knows. I seem to recall reading somewhere that a high power infer red red flashlight can cause permanent eye damage without causing you to blink, or even knowing you are looking into a light

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yea, uv as well

When I go to the eye doctor and have my pupils dilated, an intense white light is used and I have to keep my eyes open for an extended period of time. It is quite unpleasant. The spot lasts for a long time. That doesn't seem to have done any permanent damage.

I'm thinking it would take quite a dose of light from a flashlight to equal that.

Bill

PhotoWiz said:

When I go to the eye doctor and have my pupils dilated, an intense white light is used and I have to keep my eyes open for an extended period of time. It is quite unpleasant. The spot lasts for a long time. That doesn't seem to have done any permanent damage.

I'm thinking it would take quite a dose of light from a flashlight to equal that.

Bill

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I had that done to me when I was a kid. The doctor told me with HEAVY German accent, "I don't care if your eyes tear like hell. Keep them open."

It was blinding bright and very unpleasant. I was going to post this yesterday and forgot. Of course, 3 lumens at point blank is VERY bright on your eye too, so I dunno.

Any Optometrists in the house?

Well there's really two questions surrounding this:

1. Can one get away with it?
2. Is it a good idea?

For example I could with a VERY high degree of certainty drink a six pack of beer, go drive 50 miles, and get away with it. I could probably do so every day and get away with it - until some unlucky day....

But would it be a good idea? No.

I could make a really big list of analogous examples...

So I'd say yes, one can most likely get away with hitting someone (or being hit themself) with a really bright flashlight, and probably a lot of times, but it's probably not a good idea to be doing so.

We should block out the sun, or mandate the use of sunglasses everywhere, because looking at the sun can be harmful to your eyes too.

carrot said:

We should block out the sun, or mandate the use of sunglasses everywhere, because looking at the sun can be harmful to your eyes too.

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No one is suggesting blocking out the sun (or bright lights)... but we all know looking at it is a bad idea (in fact, our superior colliculus or something in the brain has evolved to reflexively look away from the sun) just like looking in a bright flashlight is a bad idea.