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FrozenGate by Avery

Must a beam go into the eye to cause Retinal Damage?

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Mar 26, 2012
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Hello, all :wave:

First time poster here who values that a board like this can be found on the net. So naturally I have a question(s) about laser safety and hope that someone more knowledgeable about these matters could answer it.

Recently my roommate (who is a douche and downright always immature) has bought a 5 mW green laser and has not shown to date any responsibility with it. He has been waving it around when he plays with it, on a few occasions coming very close to shining the beam into my eyes.

Now, from I understand about this matter, even a 5 mW can cause retinal damage, right? For one, I am utterly terrified of having any damage done to my eyes because I want to be a pilot and this would cause a huge setback to my career to have any retinal damage.

So here comes my question. How much of the beam must go into the eye before damage can occur? If the beam is shined--say, 4 feet away onto a point near to a person, and someone glanced over at the emitting source, would this cause any damage? Also to boot, would starring at the point source of the beam in a darkened room do anything to someone's vision?

I'm asking this because this is what happened to me the earlier tonight and the beam was so bright, it left an afterimage in my vision, which got me worrying. I apologize for coming across as paranoid, but I fear that this immature douche could hurt me or someone else, and that would...make me have to kick his ass. Lasers aren't a toy IHMO.
 





If it is actually 5mW you're fine, I wouldn't worry about eye damage. 5mW green is the level where you blink before it does real damage. Anything more than that and there will be eye damage before you can blink (literally). Most cheap 5mW pens are actually much more than 5mW though. Some are as high as 90mW.

But, no, the beam entering the eye isn't neccessary for eye damage at high enough powers. Above a couple hundred mW and at close enough distances the reflected diffuse light from a wall can cause permanent damage.
 
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Did the afterimage go away after a few seconds to a minute? If yes you have nothing to worry about.

So here comes my question. How much of the beam must go into the eye before damage can occur?

Direct hit from a 5mW beam, where you don't blink... there is a chance of damage. The chance is even higher if the laser is more powerful than 5mW.

If the beam is shined--say, 4 feet away onto a point near to a person, and someone glanced over at the emitting source, would this cause any damage?

No it wouldn't.

Also to boot, would starring at the point source of the beam in a darkened room do anything to someone's vision?

No.

When dealing with lasers what you have to really worry about are direct hits, and specular reflections off of surfaces like mirrors, glass, basically anything shiny. Reflections of off matte surfaces, or diffuse reflections, are not as dangerous, but can be at high powers.
 
I would tell him to stop or break that fools laser off in his arse. My eyes are too bad to be much of a pilot, I have tried, I love to fly, but my laser surgery left me with a uv issue and strong light halos, and before that I was near sighted.


If your eyes are good don't let some dick wreck them with a laser pointer of "unknown" power level.

If you must buy some laser glasses to protect yourself.

If he has an LPM and it tests less than 5mw its NP, my fleabay laser I just got for 10$ is 78mw of green and about 12mw of IR, I can burn a trash bag with it, but it looks safe, its not, if I can burn a trash bag I can burn a capillary in my retina.

You can not assume to know if a laser can hurt you, unless you KNOW what it is putting out, I bet your friend lack an LPM

ALSO I wear goggles never been hit in the eye with laser, and yet, in the last year, I have a crap ton of floaters and my eyes seem to take forever to get my rods going at night. I use allot of 1-2W lasers though :P good luck with the pilot thing, its loads of awesome, I still may become a pilot though, just not a commercial one, as a kid I wanted to be a bush pilot in AK.
 
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The above posts are right. Just because he or the laser says 5mw DOES NOT mean that it is. Be safe not sorry. Does your roomy drink? If he does wait till he passed out and drop the laser in half full beer or shove it up his a$$. Problem all gone unless he gets another.
 
When he is not around grab the laser and give it a few good whacks on something that's hard, but wont show physical damage. You could rap a leather belt around the top, and hit the table a couple of times.
 
5 mW or not, he just shouldnt mess around with it if you don't want him to - immature idiot i suppose?
 
Or just put the batteries in the wrong way:eg:

I don't know if that would work, even the cheap Chinese 532's I have dealt with always seem to have polarity protection. And believe me I know, I'm notorious for putting batteries in backwards! :D
 
I don't know if that would work, even the cheap Chinese 532's I have dealt with always seem to have polarity protection. And believe me I know, I'm notorious for putting batteries in backwards! :D

Must be my luck then... I killed two lasers by putting batteries in the wrong way :undecided:
 





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