Green lasers under 400mw no harm?

[jbtm]

Caution with the Danger of Green Laser Pointer

Wondering if this artical is fully true. They did a test with a patient that needed an eye to be removed. So they pointed a geen laser at the retina, for 60 seconds, and they said the eyes natural healing ability will fix it. If I read this article right, a laser under 400mW will not cause perm. eye damage..however this does NOT mean "Oh go point it willy-nilly at mirrors and dont care for glasses!"

Anyone know if this is true? To them, they are basically saying its safe to use a laser under 400mw, with out the worries of being blinded due to a "hit across the eye" as it will heal it self over time, and not cause any blindness. however, long exposures to lasers for long time will/can.

I just wonder, as I love to see the beam of a green laser...However, glasses destroy this purpose, as you cannot see it. It would make me feel more better to know that if i EVER! accidentally hit my eye stupidly, there's not a thing to worry about. It would also make my parents happy if that article is true, because they dont want me playing with this laser a lot (even just to see the dot on the wall on a sunny day) because they thing it will cause perm. eye damage.

 

[ElektroFreak]

False.. surely you're joking. If it'll burn your skin (which 200mW will do easily) it'll burn your retina.

 

[jbtm]

No i was just questioning the article. I didn't actually believe it was true.

I did though enjoy the fact how you can use them to heal cuts and what not...and yes, I know it will burn skin because even at 3ft it easily will...more range however, doesn't near as fast.

 

[ElektroFreak]

Range has a lot to do with it, but that's primarily due to beam divergence. If a beam doesn't expand much, then it will remain very dangerous out to a good distance.

 

[MrGreenJeans]

I would doubt the word of Daniel Rigano (the author) as his expertise is certainly not in lasers. His bio says he's an expert at search engine optimization. When an author uses the word "coz" instead of "because" in a technical description I tend to question validity of the information. Anyone too lazy to actually write out the word is probably too lazy to fully read or understand the mentioned studies and thus fail to accurately reach reasonable conclusions about laser exposure. Furthermore, I doubt the studies he read are actual research. They are probably second or third hand rewashes of the original studies; the type of stuff found in popular media.

 

[RA_pierce]

I would doubt the word of Daniel Rigano (the author) as his expertise is certainly not in lasers. His bio says he's an expert at search engine optimization. When an author uses the word "coz" instead of "because" in a technical description I tend to question validity of the information. Anyone too lazy to actually write out the word is probably too lazy to fully read or understand the mentioned studies and thus fail to accurately reach reasonable conclusions about laser exposure. Furthermore, I doubt the studies he read are actual research. They are probably second or third hand rewashes of the original studies; the type of stuff found in popular media.

My thoughts exactly.

 

[lasersbee]

I had tested the OD of a cheap pair 532nm Laser Safety goggles
with a ~300mW 532nm Laser at one time..
The goggles were held between the Laser and the LPM Thermopile
Head for aprox 10-15 seconds... The unfocused raw beam from the
Laser burnt a hole almost completely through the Safety Googles...

I can imagine what that amount of Laser Power could do to the
human retina after it IS focused by the eye's lens for 60 second...


Jerry

 

[Arayan]

I found this in the the same journal... :thinking:

Retinopathy From a Green Laser Pointer
A Clinicopathologic Study
Dennis M. Robertson, MD; Jay W. McLaren, PhD; Diva R. Salomao, MD; Thomas P. Link, CRA

Objective: To report retinopathy following exposure to
light from a commercially available class 3A green laser
pointer.
Methods: A 55-year-old woman with a ring melanoma
was scheduled for enucleation. The eye (visual acuity 20/
20) had a healthy-appearing macular retina. The retina
was exposed to light from a commercially available class
3A green laser: 60 seconds to the fovea, 5 minutes to a
site 5° below the fovea, and 15 minutes to a site 5° su-
perior to the fovea. Color photographs were obtained be-
fore and after exposure. The eye was enucleated 20 days
after exposure.
Results: Laser power measurements averaged less than
5 mW. Retinopathy was observed 24 hours after laser ex-
posure. This was characterized by a yellowish discolora-
tion at the level of the retinal pigment epithelium (RPE)
in the subfoveal region and at the site superior to the
macula where the retina received 15 minutes of laser ex-
posure. Each site developed granular changes at the level
of the RPE within 5 days of exposure. Histologic study
showed RPE damage in the exposed subfoveal and para-
foveal regions.
Conclusion: A class 3A green laser pointer caused vis-
ible retinopathy in the human eye with exposures as short
as 60 seconds.
Arch Ophthalmol . 2005;123:629-633

 

[lasersbee]

Now that ^^^ is very believable and makes more sense... IMO

BTW.. I'm in no way a clinically qualified eye expert...
but common sense is a good thing...

Jerry

 

[HIMNL9]

.....
I can imagine what that amount of Laser Power could do to the
human retina after it IS focused by the eye's lens for 60 second...
Jerry

uh ..... a hole through it, for sure ..... in the first 2 or 3 seconds ..... then, starting to burn the back wall of the eye ..... and in the meantime, part of the heat coagulate the liquid inside the eye, turning it in gelatine, and increasing the volume and the pressure in it ..... not speaking the fact that, just in the back of the eye, the beam can hit and burn directly the optical nerve .....

Considering how much the human eye is sensitive to pain, also in "normal" conditions ..... I highly doubt that anyone, including masochists, can stand 60 seconds with a laser beam that burn inside the eye .....

 

[jbtm]

Yep..Would explain why they say "Lasers above 5mw cant be imported" A lot harder to harm someone with a 5mw green than it is a 200mw green. That and people shine them at air plains...Stupid. I have a pair of glasses that blocks 200-600nM, and with focusing it, I purposely did it in a corner, and found that it indeed burn a surface etch in the orange lens. Expecting this to be true, the glasses, i did it in a place that wouldn't be noticeable

 

[AndyR]

In no way is this true, and I highly doubt the author meant to "trick" anyone into thinking it was. The author probably wrote it as a joke (made obvious by the generic "laser noob assumptions" like how green is much more powerful than red because it is brighter), and as an insult to the ignorant people at laserto.com I suppose.

 

[Cyparagon]

I saw the word "coz" in lieu of "because" and I quit reading. No respectable editor would write like that.

 

[photonaholic]

I saw the word "coz" in lieu of "because" and I quit reading. No respectable editor would write like that.

Agreed, the whole concept is frightening that someone who lacks a degree of common sense could read that rubbish, believe it and get hurt over it.

dumber than kipkay is.

 

[kingdave2357]

Damn right thats BS.... Laserto.com is a scam site run by a guy named yang zhen(possibly spelled wrong, and maybe false name) in china, when I was relatively new to lasers and before I ever new of LPF, I ordered a 55mW 'abbadon series' from them, got a confirmation email, and nothing else, ever. He wouldnt even respond to the paypal dispute, and eventually they took my money back out of his account for me. It said on paypal that he also runs highlasers.com. IMO they both are a bogus scam site intending on ripping you off, and this article was most likely published to give them press or advertisment, if you read it closely, the lack of grammer, and proper wording indicates it originated from someone not fluent in english, or a complete moron.

 

[chipdouglas]

I found this in the the same journal... :thinking:

Retinopathy From a Green Laser Pointer
A Clinicopathologic Study
Dennis M. Robertson, MD; Jay W. McLaren, PhD; Diva R. Salomao, MD; Thomas P. Link, CRA


Conclusion: A class 3A green laser pointer caused vis-
ible retinopathy in the human eye with exposures as short
as 60 seconds.
Arch Ophthalmol . 2005;123:629-633

i don't know about you guys but the only thing i will stare at for 60 seconds is woman. Although staring at a woman for 60 seconds is probably pretty dangerous too