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FrozenGate by Avery

200 mw shone in eye for split second, but had eye glasses on?

Hap said:
^This.

There isn't much you can do right now unfortunately. Honestly, I would get rid of that thing and buy your boyfriend a certified Class IIIa(<5mW) laser which he could use with the cat, and would be completely eye safe.

If you are interested take a look around the forums for some true <5mW 532nm lasers.

-Alex
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HAP!! quit already-- you do not know enough to be handing out this kind of advice!!!

let the pros help her PLEASE...

1st no laser is eyesafe - just where did you get that idea??

even a 1 mW laser can be magnified by our eye's own lens 1000 times!!

I have no problems with cats chasing the dot BUT highly do NOT reccommend lasers with some dogs-they can become extremely obsessesive with it and in reality are very unhappy -dispite their owners seeing that otherwise...

IMHO the OP does not really need to go see a Dr. when the injury is very slight they do nothing -- so $$ wasted-
while her eyeglasses may have helped.... that is not something we can figure out--scientifically.

the longest exposure anyone can get under 'normal' circumstance is no more that .25 seconds--did you know that Hap??
go read my LSO thread before passing out info--
her glasses did help IMO in this case..

hk
 
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Why do you thing the glasses helped?

Obviously they reflect a tiny bit of light away depending on incident angle, but that is no more than 10% and probably less with broadband anti-reflective coating common on glasses.

If you are near sighted and hit by a far away laser i'd reckon you could actually be better off NOT wearing your glasses, as the laser light is not perfectly focussed on the retina. For modest exposure this would spread the light over a larger area giving a lower power exposure per mm2. For a very high exposure the inverse would be true as it would damage a larger area despite being spread out.

As far as i understand these glasses are corrective ones, not sunglasses or something similar to designed to block a lot of light.
 
What no one here is mentioning is the IR component for DPSS lasers. This is generally what does more damage than the ~5mW 532nm beam. ( green light is bad enough as we are the most sensitive in this area of visible light) Usually in these cheapo dpss lasers have no NIR filtering at all. As such there is almost always a large amount of NIR throughput of up to 30-50mW even in lower power "pointers".

We don't know the true strength of the laser in question so I can only assume. No measurement done.

NIR at pump diode strength is more than strong enough to burn your retina
even if it is reflected (dependant on surface properties).
Eye exam is warranted ASAP. Better safe than sorry!
 
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Benm said:
Why do you thing the glasses helped?

Obviously they reflect a tiny bit of light away depending on incident angle, but that is no more than 10% and probably less with broadband anti-reflective coating common on glasses.

If you are near sighted and hit by a far away laser i'd reckon you could actually be better off NOT wearing your glasses, as the laser light is not perfectly focussed on the retina. For modest exposure this would spread the light over a larger area giving a lower power exposure per mm2. For a very high exposure the inverse would be true as it would damage a larger area despite being spread out.

As far as i understand these glasses are corrective ones, not sunglasses or something similar to designed to block a lot of light.
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Yeah, this was what I was thinking. I have glasses for myopia and I'm sure I would be better off if not having them on. I tried shining a laser though them and it didn't seem to block any light at all.
 
paul1598419 said:
Yeah, this was what I was thinking. I have glasses for myopia and I'm sure I would be better off if not having them on. I tried shining a laser though them and it didn't seem to block any light at all.
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Also a good point. :thanks: Glasses also won't filter NIR which I am concerned about in this instance.
 
Seoul_lasers said:
Usually in these cheapo dpss lasers have no NIR filtering at all. As such there is almost always a large amount of NIR throughput of up to 30-50mW even in lower power "pointers". !
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I used to be quite paranoid about this as well, until doing some, admittedly rather poor "testing".

Used non IR filtered goggles to test multiple cheapo lasers, and viewed the ir dot/halo at a distance of 5 and 10 feet, using a cellphone camera. The IR diverges very quickly.

My LPM also didn't pick up any reading from multiple cheap lasers at anything past 3 feet, with green blocked.

I agree, there is a danger close up, but at any distance the hazard from IR seems minimal.
 
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I did not mean that eyeglasses were a BIG help==just a small amt. reflected --pretty much the same as fog or haze lowers the power (very slight)
 
Damn, all the drama in this thread...
OP hasn't even been on the forum in 20 days.
 
I agree with the IR thing. I have a 3W c-mount 808nm that puts out about 4W with 5A that I just need a driver for to complete and testing it out you have to be close to it to pick it up. I don't believe at this point that the IR component of a 532nm is a worrisome factor unless you are pretty close to it and it's quite high. Don't try and nail me down with this as I need to test it out more. As far as any cheap overspec 532nm goes I think the IR portion there has had too much sensationalism behind it because you can't see it. I would be far more concerned with that nasty bright dot.
 
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Pman said:
I agree with the IR thing. I have a 3W c-mount 808nm that puts out about 4W with 5A that I just need a driver for to complete and testing it out you have to be close to it to pick it up. I don't believe at this point that the IR component of a 532nm is a worrisome factor unless you are pretty close to it and it's quite high. Don't try and nail me down with this as I need to test it out more. As far as any cheap overspec 532nm goes I think the IR portion there has had too much sensationalism behind it because you can't see it. I would be far more concerned with that nasty bright dot.
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The discussion on the dangers of IR leaking from cheap DPSS pointers has been going on since I started the hobby - and I imagine well before that too. It keeps bouncing around between "IT'S DANGEROUS, YOU MUST USE AN IR FILTER/IR GLASSES" and "Nope, it diverges too quickly/isn't powerful enough".

I don't think I've seen any cases of someone getting eye damage from the IR portion of an unfiltered DPSS pointer. Certainly if one had the laser opened up for repairs there's a significantly increased chance of damage from the IR portion.

The power of the IR emission also usually isn't terribly high. Keep in mind, any IR that does leak through isn't being used in the DPSS/SHG process - so efficiency is reduced. DPSS cavities (At least the basic kind we're familiar with) are designed to absorb the the pump wavelength and contain the fundamental wavelength (1064nm in the case of 532nm). Nd:YVO4 does a FANTASTIC job of absorbing 808nm and should absorb all of it with the right length of crystal and dopant percentage (Hint: The crystal doesn't need to be long at all, few mm at most with typical CW pumped dopant %). Crystal coatings should mostly filter out the 1064nm, although coatings aren't ever perfectly 100% reflect.


Combine that with the high divergence and you end up with something that is very unlikely to cause damage. Without fancy optics you're never going to collimate both the IR portion and the green portion and have good divergence on both either.


Edit: That said, always better safe than sorry! :)
 
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And there's the rub. Always having to add the edit when posting about it;) Always someone out there who believes the rules don't apply to them or will claim we said it was safe so it's not my fault I shoved it in my eye til it came out the back of my head.
 
Pman said:
And there's the rub. Always having to add the edit when posting about it;) Always someone out there who believes the rules don't apply to them or will claim we said it was safe so it's not my fault I shoved it in my eye til it came out the back of my head.
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Yes exactly - didn't want someone coming back saying "I deliberately pointed my green laser into my eye with my glasses for 532nm on and now I have retinal damage from the IR - I was told the IR was safe!!!".

Chances are with responsible use the IR leaking from a 50mW Chinese greeny isn't going to cause damage - but why risk it? As with all high power laser operation - you only get the one set of seeing balls - best to use common sense, operate safely and use the right protective equipment when necessary.
 
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