A Plea for EYE Safety!!

Lol, I just tried it but gave up after question 15, just too many questions for my attention span, lol. But yeah I love green, and would hate to loose perception to it, hell Id rather sell my 445nm's before Id loose my green vision....

my 445 spread . . . via Noir . . .

AL2 and ARG . . .

boscoj said:

my 445 spread . . . via Noir . . .

AL2 and ARG . . .

Click to expand...

Boscoj, you could post some beam and dot shotzs through both of those goggles, as some testing, and post that on your thread "Woot lasing commence" or something like that, and link it here.

It would be great to see how those goggles perform!

I plan on it once I get my LaserBee power meter aypal:

Eudaimonium said:

Boscoj, you could post some beam and dot shotzs through both of those goggles, as some testing, and post that on your thread "Woot lasing commence" or something like that, and link it here.

It would be great to see how those goggles perform!

Click to expand...

kingdave2357 said:

So how much blue exposure does it take to weaken the visibility of green light anyway, and does it last for a while or does it go away in a few minutes/hours. Im not talking about accidents or hits, just exposure to excess 445nm in class IV powers with normal use. Its almost like green isnt as bright as I remembered it, but is it because I am used to it now, or because of the 445nm?

Click to expand...

The green loss is prolonged exposure to blue, its mainly documented in eye surgeons exposed to 488 nm backscatter leakage and aiming beams on a daily basis. Ie Argon laser photocoagulators. They get the green vision back after 4-6 months of ceasing to use the argon. The aiming beam is 1-7 mW and the backscatter is 250 mW- 500 mW hitting the patients eye. There is a safety shutter that closes to prevent direct exposure during the treatment. They get full color response back in a few months after stopping intense blue exposure.

For a short term exposure to 445 you should have normal vision back in seconds. If not, its time to get distance and attenuation between you and what ever the scatter source is. In fact you should NEVER get to the level where you have afterimages. Its normal to need a few minutes to adjust after wearing deeply colored safety glasses or sun glasses.

Steve

LSRFAQ said:

The green loss is prolonged exposure to blue ... For a short term exposure to 445 you should have normal vision back in seconds. If not, its time to get distance and attenuation between you and what ever the scatter source is. In fact you should NEVER get to the level where you have afterimages...

Click to expand...

Thanks for the info Steve!
I do note "afterimages" when using either my 130mW 532 or my 650mW 554nm lasers, but said afterimages last for about 30s and are only really noticeable if I close my eyes. A "direct hit" from my Canon 580EX (which sports a GN of 42) is worse, though, so I think as long as the afterimage is gone in <60s we should be ok?

Traveller said:

Thanks for the info Steve!
I do note "afterimages" when using either my 130mW 532 or my 650mW 554nm lasers, but said afterimages last for about 30s and are only really noticeable if I close my eyes. A "direct hit" from my Canon 580EX (which sports a GN of 42) is worse, though, so I think as long as the afterimage is gone in <60s we should be ok?

Click to expand...

Studies show its cumulative, and perhaps/does come back to bite you when your in your 40s, when macular degereration starts. There is some mild truth to the "blueblocker/UV blocker " sunglasses rage in the US.

Gone in 15 seconds would make me much happier.
Inverse square law is your friend. Add distance or turn down the beam.

I have to be intensely careful with this long term issue, because I work with arc, metal vapor, plasma, laser, and diode sources as how I make my living.

Summer sunlight at the equator is roughly 1.1 kilowatts per square meter at noon. If I did my math right there are 1,000,000 square millimeters in a square meter. So doing a little division you get 1.1 mW per mm^2. A 100 mW laser beam (lets assume hene like properties, and .65 mm diameter beam) at a short distance gives you better then 100 mW per square mm. (in fact a .65 mm diameter hene beam has a area of .33 mm^2, so about 2.8 times more power per area then a 1 mm^2 beam) say 280 mW per mm^2. So its safe to say your spot is 100x greater then the sun light your eye was designed for or adapted to. Provided the spot is the same distance away as the ground you normally look at, and assuming a diffuse cosine scattering surface.

You get the idea.

I just had a little something to drink, so some one check my math. I rarely drink, for medical and religious reasons. I'm sure math plus alcohol = error.


A little correction, now that I'm more sober. Maybe 150 watts of that one point one kilowatts per meter is visible or near IR and gets past the cornea. So the sunlight/hene ratio is a bit off, but the hene is still roughly 100 times brighter and the pointer 100 x that.

You get the idea.

.

Steve

^ Good info. +1 I thought "drinkin" whisky was for medicinal purposes? ;-)

Your math looks good to me!
Macular degeneration is never a good thing and while my "ex" re-attaches retinas for a living (posterior surgeon), I don't think there's much that can be done for macular degeneration (particularly at an older age )... if you're still young, make sure to eat those carrots...

hi just a quick question, lets say im in my room and i shine my 400mW 447nm blue laser at the painted white wall and im about 4 meters away can looking at the dot on the wall for less than a second do any damage?

As long as your wall is painted matte white, that would be fine.

Be careful though, most paints sold as matte have sone nasty reflection angles stronger than expected, making protective eyewear a reuirement until you can assert your situation properly.

thanks :yh:

I agree completely, as a new member, LPF has helped me to realize that safety is first and I am currently planning on purchasing a pair of very nice goggles along with my first laser.

Goggles are always a good idea, though you will at some point take them off to observe the result of your experiments in full glory.

This does pose a bit of a risk, since the goggles may completely obscure specular reflections that are quite powerful, but seem neglible when looking through your protective eyewear.

For that reason i think its good to have an adjustable current source that allows you to ramp up the power slowly in case you do want to see it without eye protection at some point. The specular reflections will become evident before really dangerous if you do that, and if you notice any, you have the option to cancel the experiment before serious harm is done.

This didn't used to be a big problem, but with these 1 watt+ lasers emerging, getting a 1% reflection is already a potential danger, and things like windows will easily refect a few percent in directions you do not want them too.

With the 200 mW or so green lasers getting a reverse hit from a window reflection at 4% reflection resulted in 8 mW into your eye - a bit above what is considered acceptable, but not extremely dangerous. With these 445 lasers that 4% reflection represents a 40 mW direct hit in the eye, which is truely dangerous.

You wouldn't point a 40 mW green straight into your eye on purpose, so be careful not to it with a 445 nm reflection by accident either!

I agree with everything said on here. I'm new and will be getting good protection, and will be buiding my first laser soon.

I'm ex-military 29yrs old, in network engineering, and responsible. I've had hobbies before, all of which have been based on technology and engineering. Cars, PCs, electroncs, motorcycles, network engineering, etc...

They were always too expensive for me though, and I'm thrilled to finally find something that doesn't cost too much!

For those new guys out there, don't be stupid and make officials make laws and also drive up the price!

For those vets out there, worried that new people will be stupid, don't call crapio and drive up the price, please!

This is a great thread. Whenever I start building some lasers (probably a 100w 405nm first), I'll be getting these goggles from OEM: OEM Laser Systems KRY Goggles

Thoughts?

I'll be getting another pair from them for when I build some green/red lasers later on, assuming they're up to snuff.

My only question is... Why isn't this a global sticky? (Viewable in all forums).