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Minimum safe power rating for viewing without glasses?

ejhs24

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I'm new to lasers (an absolute novice) and I'm considering purchasing a handheld model. But what would be the minimum mW rating that I could look at without glasses, without risking any damage to my eyesight? Bit of a mouthful, but thanks in advance for the help.
 
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Alaskan

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So much depends on variables, how close will you observe the spot, assuming this is what you are referring to? What kind of surface? Some are far more reflective than others. What wavelength? As a general rule, if when you look at the spot and look away, if you see a residual in your vision from looking at it which lasts more than a few seconds, that is probably too much.

We had a member a few years ago who has appeared to have passed, missing after an illness, Allan would say if you see a spot after looking away which lasts 30 seconds, that was too much, I am far more conservative.
 

green lasers rock

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I agree wit Alaskan and would simply say “it depends”. Only lasers below 5mw are almost always safe.

Also depends what surface you point the laser at. You will get much more reflection off a white wall than a dark patch of soil. These are all considerations.
 

Jirkas99

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I'd say 10 - 30 mW. I'm feeling uncomfortable looking at dot at anything above 50 mW in 532 (green). Exception are ofcourse near invisible wavelengths such as 405nm (violet) or 700nm (dim red) (they look dim but can burn your eyes out as easy as for example common 532nm laser). You should wear safety glasses when there are reflective surfaces even with lower powers (but whats the point when you can't see the beam).
 

kecked

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1mw start there. That way if you happen to flash yourself you likely will survive it. 5mw should ok too. Just don’t be stupid and look down the beam or such.
 

paul1598419

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If you are concerned about viewing diffuse reflections above 30 mW you will likely never see a laser show. They are mostly all considerably higher in power than that. That being said, diffuse reflection are like a point source of noncoherent light, The intensity decreases as the square of the distance you are from it. I personally look at diffused reflections of lasers higher than 3 watts at a distance of ~12 feet. Not a problem for me.
 

kecked

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For shows sure. The beams moving. I watch 2w everyday for a long time with no effects from 10 feet away. BUT until you are comfortable 5mw in a pointer. I can see you hit a window or such and take a strike.
 

Jirkas99

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Just saying for me its around 30mW. At this power I can stare at the dot all day long. At 100mW after 10 seconds I have to look away because I have some flash blind spots just like when you look into the sun. At around 1W I see a spot in front of me instantly. Tested this today. I shined all 3 lasers one by one at wall that was 3 - 4 meters away from me. Color of wall is white. Lasers used were in ranges of 525 - 535nms (don't have spectrometer).
At other WLs power on which you can look without having flashblindnes will be slightly diferent. At other distances power will be slightly diferent. And your eyes are diferent than my and will maybe percieve dot diferently.
You can look at spot of higher power (but you shouldn't) than 30mW 40mW on wall but as power will go up comfort will go down. Outside is it a another story ofcourse.
 
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paul1598419

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If you are getting some flash blindness from diffused reflections at 4 meters, just increase the distance. You will find that the intensity decreases as the square of the distance you are from the spot. At 6 meters it will be less intense and will likely not cause you this concern.
 

lasersbee

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I'm new to lasers (an absolute novice) and I'm considering purchasing a handheld model. But what would be the minimum mW rating that I could look at without glasses, without risking any damage to my eyesight? Bit of a mouthful, but thanks in advance for the help.
Hmmm... :unsure:
I would suggest no more than 5mW without Laser Goggles/Glasses.

Jerry
 

IceFireForce

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You will not easily get flash blindness off from a 455 nm laser, even less so from 405, so don’t rely on flash blindness to be your red flag. I observed the dot of a 455 from 1 meter on soil and while burning paper for about 30 seconds total and watched the beam in dark sky twice. My vision appears to be a somewhat blurry when looking towards a source of light and I seriously consider my quick lesson to have had a pretty bad effect on me. I would say too, nothing above 5 mw should be looked at without glasses ever, and by the way, it is ridiculous they sell 1W lasers with those stupid “light effect” caps making you think they are to be observed and watched as this damages your eyes.
 

paul1598419

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Have you seen an ophthalmologist to confirm your laser damage to your eyes? If not, you are only speculating as to the cause of your "blurry vision". People have many different reasons for being unable to focus their vision and it is rarely if ever from looking at nonspecular reflections of lasers.
 




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