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My Eyes! My Eyes!

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Now, what I want to know is. Would you all the guys who know more about this than me wear safety goggles to operate a 15mW green laser show system which isn't intended to aim at anyone? (even if it's just a mirror atached to a speaker)
 





Jaseth

Jaseth

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@ Albert
Yes, definitely.
If I do not control the laser myself constantly (that means no randomly moving mirrors, no random reflections, no letting friends try), I treat it as if I WILL get a direct shot, and therefore goggles are necessary.

Seb
 
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CT Lasers

CT Lasers

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honestly? No, I do not wear safety goggles when i operate my lasers at shows. I DO wear them when aligning, setting up, cleaning, maintaining and performing any other tasks with my lasers where the beams and effects are not 100% known and planned out.

My response previously was not to preach about wearing goggles. My response was to dispell the false defenses on *why* lasers may not hurt you (or someone else).

I dont think anyone here is dumb or obviously out to hurt them self or anyone else. but accidents happen when and if you are misinformed. "a fast moving laser beam is not as dangerous because it is moving too rapidly" is one of those misinformations. Also, blink reflex does us no ggod when you get into the realm of 500mW+ ranges of lasers. We also need to take into account wavelengths.

Our eyes will respond much differently to a 405 beam than to a 532/635 beam. These phenomenon's are IMPERATIVE to understand if you are factoring MPE's for safe Laser exposure. (MPE= Maximum Permissible Exposure. In case someone was unaware of its meaning.)

are the dangers with a 15mW/532 laser very miniscule? YES! extremely miniscule under normal, responsible operating conditions. i am not into providing a false sense of danger to get a point across. but again, many reasons i had read and heard as defenses to validate the "safeness" of a 15mW beam are incorrect and therefore can provide a dangerous situation where someone *COULD* have the possibility to be injured.

-Marc
 
L

LSRFAQ

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Hallucynogenyc said:
Now, what I want to know is. Would you all the guys who know more about this than me wear safety goggles to operate a 15mW green laser show system which isn't intended to aim at anyone? (even if it's just a mirror atached to a speaker)
Click to expand...

One, if its in a case designed to meet 21 CFR 1040.11-J
Two, If I have masking on to prevent it from going where I don't want it
Three, If its constructed soundly enough that I'm sure it wont rip apart.
Four, If I have a way to quickly terminate the beam
Five , If I have my room secured from entry by others
six, If I'm sure of my target screen..

well, maybe yes if 1-6 are met.

Keep in mind I had to do laser safety for 20 university grad students.. I've seen what can go wrong in even a "safe" inspected environment, not to mention the laser show world...

So I try to practice what I preach..

Some Laser show safety rules in pictures, well at least the public viewing side of it:

Datailed Laser Safety - Safety Archives - www.LaserFX.com

Steve
 
D

Deleted member 8382

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Well, so let's all agree on this so we can end the discussion.

"Although the risk exists, it's so low that under this conditions and assuming no lame things are going to be done with it I wouldn't buy goggles for this"

Sorry if my posts seemed to mean anything else ;)
 
Benm

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Traveller said:
Ben, I can't believe I'm reading this from you, with all your experience... :tsk:

LIGHT TRAVELS [much] FASTER THAN YOUR REFLEXES, PERIOD.
Click to expand...

Obviously that is not what i meant:

The blink reflex is largely triggered by the apparent brightness of a light source. This has nothing to do with the speed of light, only with the speed in which thermal damage is done.

If i were to shine 1 mW lasers into your eye, you would simply blink faster with a 532 compared to a 660nm laser (dont even go to 780/808) because it appears that much brighter, causing a painful sensation.

There are two mechanisms of pain from exposure to light: The primary one is optical overload, which also occurs when you move from a dark room to brightly lit environments. Daylight can feel painful to the eye after being in a dark area, even though it poses no danger in sense of actual power. Still, this sensation will cause you to shut your eyes, or a good deal of pain when you cannot afford to (like looking into the sun after a turn when driving just before sunset).

The other mechanism of pain is actual thermal damage, literally getting your retina 'fried' by the sheer power in the light. This effect will occur even with invisible wavelengths, but by the time it does, it is far to late to close your eyes since the damage has been done.

Interestingly, the first mechanism is sensitive to conditioning. Playing around with a laser on a bright sunlit day can be more dangerous than doing so in a dimly lit environment. The problem is that your eyes adapt to the brightness of the environment, and will percieve a certain power level of light as less intense at that time.

This effect is somewhat counteracted by pupil contraction: in bright conditions your pupils will contract to accomodate the intensity. This would allow less laser light into your eye when exposed, minimizing damage. Keep in mind though: pupil contraction is only a short term mechanism, and your pupils will expand to normal size when the retinal sensitivy adjusts in normal daylight conditions.
 
L

LSRFAQ

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Hallucynogenyc said:
Well, so let's all agree on this so we can end the discussion.

"Although the risk exists, it's so low that under this conditions and assuming no lame things are going to be done with it I wouldn't buy goggles for this"



NO, I'm not going to agree..

CAUTION< RANT MODE IS ARMED< AND ACTIVE. FOX ONE! RANT MODE...

Here is the issue. Retinal burns seem to be a Badge of Honor on this board. To quote one of my friends, being critical of this thread, "OH, I took Eleventy billion Milliwatts in the eye and I cant see any damage so it must be safe...". That friend worked on submarine nuclear reactors, his sole job was to sample the whole sub every day, looking for exposure leaks. On a daily basis, he "interfaced" with the primary coolant loop, ie THE HOT SIDE of the reactor.. Interfaced means somehow 'tap into" the coolant loop. I think he knows what he's talking about when it comes time to "DO SAFETY".

THE CORRECT PATH IS A ZERO SOCIAL TOLERANCE FOR ANY EYE DAMAGE AND ANY POSSIBLE CAUSE OF EYE DAMAGE.

For USAians, familiar with the public service ads on TV, Here is the new version: "ONLY YOU CAN PREVENT RETINA FIRES".

No one here has looked at cumulative damage. No one here admits that you can have damage and not know about it.

NO ONE HERE MENTIONS IRRADIANCE, ITS ALWAYS POWER. WELL,,,,, POWER IS ONLY HALF OF IT! POWER PER UNIT AREA IS THE CRITICAL FACTOR..

You most possibly would not know if you had damage in the peripheral vision, until the truck hits you, and God tells you at your Judgement Day!!!...

REP and saving ones rep from mistakes seems more important then bothering to look up the safety issues. Your culture chases away those who do try to help you....

Many people here assume because someone, some place, in the world can do something (audience scanning) you can make simple assumptions and go out and do it with no gear, no precautions, and no training. Your so interested in "freedom" to play with dangerous things that the majority of you do NOT do your homework... You allow guesses and mis-statements of fact to flourish... In this system, in a analogy, 95% of you here would defend some one's so called "RIGHT" to attempt to fly a 747 New York to London, with PAX, having never had flight training... Wake UP, Freedom is NOT FREE, You have to earn it.

EARNING IT means doing the math and taking the time to do it right, and spend the money, if needed , to do it safely. (ref: Home made safety glasses threads) Earning it means starting small and working your way up. In the 1980s and early 90s, high power for a hobbyist was 5 mW of hene. 100 mW was 3000$. It was easier then to educate potential buyers of hazards. Now, 200 mW is a first buy. The regulations and societies rules have NOT coped with the technological change!


LASER POINTER FORUMS NEEDS TO DEVELOP A "CULTURE OF LASER SAFETY" ON THIS BOARD!

YOU NEED TO CENSOR AND SANCTION THOSE WHO STATE THINGS WITH REGARDS TO SAFETY, WHEN THOSE STATEMENTS ARE WRONG!

I could easily give you the means for MPE determination, but I'd very scared people here do NOT have the discipline to use it to learn from, but would try viewing laser light.

FROM NOW ON HERE, THE CORRECT ANSWER ON HOW MUCH DIRECT LASER LIGHT CAN ENTER THE EYE SAFELY IS ZERO!

THE CORRECT ANSWER ON HOW MUCH INDIRECT REFLECTION IS SAFE, IS "IT MUST BE MEASURED, IT DEPENDS ON MANY VARIABLES"

The late A. C. Clark's 3rd LAW said " Any sufficiently advanced technology is indistinguishable from magic."

The problem is, the hazardous magic "wand" is now available for less then 100$. BUT ALMOST NO ONE HERE GOES TO HOGWARTS BEFORE THEY GET THE WAND!

PLEASE WORK TO END THE IDLE< ILL INFORMED< MERE SPECULATION< THAT OCCURS ON SAFETY HERE!

TIME, POWER, AREA, IRRADIANCE, CUMULATIVE EXPOSURE, WAVELENGTH, DIVERGENCE, BEAM QUALITY, SECONDARY HAZARDS,
REPETITION RATE, PULSE LENGTH, DISTANCE, BEAM PATH, OPTICALLY AIDED VIEWING, MENTAL STATE, THEY ALL MATTER!!!


FOR THOSE OF YOU WHO DO TRY, THANK YOU!! FOR THE REST OF YOU, JFC!, PLEASE MAKE A SERIOUS, PEER REVIEWED, FACT CHECKED, SAFETY STICKY!!


END RANT....

Steve
Click to expand...
 
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mfo

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LSRFAQ said:
Hallucynogenyc said:
Well, so let's all agree on this so we can end the discussion.

"Although the risk exists, it's so low that under this conditions and assuming no lame things are going to be done with it I wouldn't buy goggles for this"



NO, I'm not going to agree..

CAUTION< RANT MODE IS ARMED< AND ACTIVE. FOX ONE! RANT MODE...

Here is the issue. Retinal burns seem to be a Badge of Honor on this board. To quote one of my friends, being critical of this thread, "OH, I took eleventy billion Milliwatts in the eye and I cant see any damage so it must be safe...". That friend worked on submarine nuclear reactors, his sole job was to sample the whole sub every day, looking for exposure leaks. He knows what safety means and how to do it...

No one here has looked at cumulative damage. No one here admits that you can have damage and not know about it.

You most possibly would not know if you had damage in the peripheral vision, until the truck hits you, and God tells you at your judgement...

REP and saving ones rep from mistakes seems more important then bothering to look up the safety issues.

Many people here assume because someone, some place, in the world can do something (audience scanning) you can make simple assumptions and go out and do it with no gear, no precautions, and no training. Your so interested in "freedom" to play with dangerous things that the majority of you do NOT do your homework... You allow guesses and mis-statements of fact to flourish... In this system, 95% of you here would defend some ones right to attempt to fly a 747 New York to London, having never had flight training...



YOU GUYS NEED TO DEVELOP A CULTURE OF LASER SAFETY ON THIS BOARD!

YOU NEED TO CENSOR AND SANCTION THOSE WHO STATE THINGS WITH REGARDS TO SAFETY, WHEN THOSE STATEMENTS ARE WRONG!

I could easily give you the means for MPE determination, but I'd very scared people here do NOT have the discipline to use it to learn from, but would try viewing laser light.

FROM NOW ON HERE, THE CORRECT ANSWER ON HOW MUCH DIRECT LASER LIGHT CAN ENTER THE EYE SAFELY IS ZERO!

THE CORRECT ANSWER ON HOW MUCH INDIRECT REFLECTION IS SAFE, IS "IT MUST BE MEASURED IF ABOVE 5 mW"

The late A. C. Clark's 3rd LAW said " Any sufficiently advanced technology is indistinguishable from magic."

The problem is, the hazardous magic "wand" is now available for less then 100$. BUT ALMOST NO ONE GOES TO HOGWARTS BEFORE THEY GET THE WAND!

PLEASE WORK TO END THE IDLE< ILL INFORMED< MERE SPECULATION< THAT OCCURS ON SAFETY HERE!

END RANT....

Steve
Click to expand...

Well said Steve. The difference between you and I is I'm tired of trying to explain that to people.
Click to expand...
 
photonaholic

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Mr. googfan needs more rep, I just can't give it to him again yet... - rep that is.

This kid is so full of himself it stinks.

Nuff said.!!

goog.gif
 
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Jaseth

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Thank you Steve, I have a feeling I will give people a link to your post an awful lot of times in the future.
It had to be said and you said it with authority :beer:

Seb
 
Benm

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LSRFAQ said:
Hallucynogenyc said:
FROM NOW ON HERE, THE CORRECT ANSWER ON HOW MUCH DIRECT LASER LIGHT CAN ENTER THE EYE SAFELY IS ZERO!

THE CORRECT ANSWER ON HOW MUCH INDIRECT REFLECTION IS SAFE, IS "IT MUST BE MEASURED, IT DEPENDS ON MANY VARIABLES"
Click to expand...

There is just no scientific basis for making both these claims. Either one of the must be incorrect, or you should somehow explain how light magically changes to a less dangerous type of radiation when it reflects off of something (glossy or matte for that matter).

If you determine any safety limit on how much light of a given wavelength can enter the eye without risk (or with acceptable risk), there is no difference whatsoever on -how- that light enters your eye... directly from the laser, bouncing off a mirror, or a bright dot on the wall accross the room. It is the quantity that matters, not the delivery route.
Click to expand...
 
Meatball

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LSRFAQ,

Its very refreshing to hear such authoritative, and straight up information again. You are very knowledgeable, and I only wish I could read this kind of information on the forum more often. We used to have more people here kind of like you, and I wish they hadn't left, so I'm glad that you share the things you do. Thank you!

-Tyler
 
L

LSRFAQ

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If you determine any safety limit on how much light of a given wavelength can enter the eye without risk (or with acceptable risk), there is no difference whatsoever on -how- that light enters your eye... directly from the laser, bouncing off a mirror, or a bright dot on the wall accross the room. It is the quantity that matters, not the delivery route.[/QUOTE]
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Ok, from your point of view, we should therefore, under circumstances where the majority of end users have no instruments, depend on product claims made by unscrupulous manufacturers? Thus telling end users that they are safe to do a given action with that "untested" product... ??

In other words, a Auto de Fey of sorts? (Act of Faith)

If you don't have hard numbers, practice says zero exposure to a direct beam..

ANSI 136 says NO exposure...

21 CFR 1040 says below class IIIA on my variance for staff and class II for performers and class I for my audience..

Good Practices says you avoid a direct beam and use the least power possible.

So unless you have measured numbers, the exposure is zero, zip, nada..

In nations where it its legal, audience scanning requires measurements of each effect and a evaluation of cumulative exposure.
And in Germany, usually a TUV inspection as well as a safety course.

Science may say light is light... But safety practices say you must evaluate the hazard on a case by case basis...

So, if you have NO means to evaluate the hazard,you teach people to avoid the hazard..

A case in point, it is commonly cited here that diffuse reflections from 3B (visible powers below 500 mW ) are safe. Well, that is POWER, not Irradiance. So until you measure the irradiance, you cannot tell someone that a 500 mW beam from a unknown surface 6 inches from the eye is safe. I've seen it many times here, diffuse reflection posts mentioning power without distance.
While there is a scale to measure "gloss", there is no easy way to relate that to scatter..

So again, safety practice says "ZERO" irradiation allowed, until you measure.

The idea is to get people to move that beam to long distances from the eye.
Generalizations and Guesses cause hazards.

Yep, I may be approaching this from the "zero tolerance" attitude, but unless you have measurements and experience, there is NO other place to start.


Again, I have to stress Irradiance, NOT power...

Steve
 
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