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At what mW  do i need to wear goggles

ben74

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If i am careful with my laser then whats the highest mW i can go to before i need safety goggles.
 



Razako

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ben74 said:
If i am careful with my laser then whats the highest mW i can go to before i need safety goggles.
That's a hard question to answer. If you only point the laser up into the sky or at objects thousands of feet away you could even use a multi-watt green laser without worrying about goggles. If you are using the laser inside or in any place where direct reflections are a hazard then goggles are heavily recommended for anything >30mw.
 
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30mW is generally considered the end of the "safer" power of lasers. Like Razako said you'll need goggles for anything above that.
 

Zom-B

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When looking at the spot (eg when burning stuff) then multiple factors play a role; beam spot size, duration, color and ambient light.

{--} inaccurately formulated dangerous advice removed
 
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Re: At what mW  do i need to wear goggles

Zom-B said:
When looking at the spot (eg when burning stuff) then multiple factors play a role; beam spot size, duration, color and ambient light.
Another trick to lower the risk is to not look directly at the spot, but at various points around it. This keeps the spot moving on your retina so it doesn't stay in one place for a longer time.

For example (guesses from experience) in a semi-dark room, and using my trick:
240mW red is safe when focused to a sharp point, for 10-15 seconds
200mW blue-ray is safe when focused to a sharp point, for only a couple of seconds, because the color is much less bright and the iris does not shrink.

Sorry to say this, but this is probably the worst safety advice I've read here so far. Real safety cannot be achieved by tricks. And blu-ray is NOT more safer to the eyes because it is less bright.
 

daguin

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Zom-B said:
When looking at the spot (eg when burning stuff) then multiple factors play a role; beam spot size, duration, color and ambient light.
Another trick to lower the risk is to not look directly at the spot, but at various points around it. This keeps the spot moving on your retina so it doesn't stay in one place for a longer time.
For example (guesses from experience) in a semi-dark room, and using my trick:
240mW red is safe when focused to a sharp point, for 10-15 seconds
200mW blue-ray is safe when focused to a sharp point, for only a couple of seconds, because the color is much less bright and the iris does not shrink.

These ideas/recommendations are [highlight]NOT [/highlight]safe! Laser light takes [highlight]less than a second[/highlight] to burn the retina!!!!!!! Damage can happen before you can blink

Zom-B, at the powers you are playing with, you should be much more careful AND familiarize yourself with both the dangers of laser light and proper safety practices. A burn across your retina would be problematic. Blind spots would be a pain in the A**. An unlucky burn across your optic nerve would change the course of your life forever.

As Petrovski said, 405nm is NOT safer. If anything it is more dangerous. NOT because it is brighter, but because it appears dimmer. 200mW of green laser light LOOKS bright and dangerous, so you have the tendency to be more careful. 200mW of blu-ray laser light doesn't LOOK as bright, so the tendency is to relax your watchfulness.

You only get two chances!

Peace,
dave
 
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Re: At what mW  do i need to wear goggles

Not to mention 405nm light can have biological consequences beyond your normal worries of burning your retina. Skin cancer, cataract/glaucoma issues, etc. 405nm ain't deep UV or anything, but its still another added risk you gotta take into account when you work with such light (laser or otherwise).
 

Razako

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pseudonomen137 said:
Not to mention 405nm light can have biological consequences beyond your normal worries of burning your retina. Skin cancer, cataract/glaucoma issues, etc. 405nm ain't deep UV or anything, but its still another added risk you gotta take into account when you work with such light (laser or otherwise).
Are you sure about the skin cancer from 405nm part? 405nm isn't really what you would call hazardous short wavelength UV. Maybe if you left a strong blu-ray burning your skin for hours a day you might have problems, but otherwise it should be harmless. People don't get cancer from those cheap UV flashlights for revealing invisible ink/checking money and those are probably shorter wavelength than a blu-ray.
 

daguin

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Razako said:
[quote author=pseudonomen137 link=1217088543/0#6 date=1217185012]Not to mention 405nm light can have biological consequences beyond your normal worries of burning your retina. Skin cancer, cataract/glaucoma issues, etc. 405nm ain't deep UV or anything, but its still another added risk you gotta take into account when you work with such light (laser or otherwise).
Are you sure about the skin cancer from 405nm part? 405nm isn't really what you would call hazardous short wavelength UV. Maybe if you left a strong blu-ray burning your skin for hours a day you might have problems, but otherwise it should be harmless. People don't get cancer from those cheap UV flashlights for revealing invisible ink/checking money and those are probably shorter wavelength than a blu-ray.[/quote]


I thought we already had a "lasers will give you cancer" guy on the list. Maybe it was pseudonomen, but I don't think so.

Peace,
dave

P.S. If you kick off your shoes, you'll probably find that typing/talking about lasers will make your feet stink as well
 
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Zom-B said:
When looking at the spot (eg when burning stuff) then multiple factors play a role; beam spot size, duration, color and ambient light.
Another trick to lower the risk is to not look directly at the spot, but at various points around it. This keeps the spot moving on your retina so it doesn't stay in one place for a longer time.

For example (guesses from experience) in a semi-dark room, and using my trick:
240mW red is safe when focused to a sharp point, for 10-15 seconds
200mW blue-ray is safe when focused to a sharp point, for only a couple of seconds, because the color is much less bright and the iris does not shrink.


When you get 200mW or red focused to the point of little white flashes, it can be dangerous. The flashes are quick and often and can leave your eyes damaged from the light. I know if i try to burn something with my DX 200 red after like 5 sec of burning in the dark im left with a nice little bur spot right in the center of my optical acuity. Hense forth i have stopped using my laser.
 
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Federal Laser Product Performance Standards, considers 0.385mW. to be the MAXIMUM AMOUNT of LASER LIGHT that should be ALLOWED into your EYES! :eek: This information was collected from 3 different sources;#1-CDRH (CENTER FOR DEVICES & RADIOLOGICAL DEVICES, #2-ANSI (AMERICAN NATIONAL STANDARDS INSTITUTE, & #3-OSHA (OCCUPATIONAL SAFETY & HEALTH ADMINISTRATION :eek: I thought that this was important enough to post so EVERYONE would be aware of how SMALL of an amount of laser radiation has the POTENTIAL to do damage to your precious eyesight! So, PLEASE, for your own peace of mind, PROTECT YOUR PRECIOUS EYES! You only have two, & there ain't no more! phoenix77/rob :cool:
 

Razako

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phoenix77 said:
Federal Laser Product Performance Standards, considers 0.385mW. to be the MAXIMUM AMOUNT of LASER LIGHT that should be ALLOWED into your EYES! :eek: This information was collected from 3 different sources;#1-CDRH (CENTER FOR DEVICES & RADIOLOGICAL DEVICES, #2-ANSI (AMERICAN NATIONAL STANDARDS INSTITUTE, & #3-OSHA (OCCUPATIONAL SAFETY & HEALTH ADMINISTRATION :eek: I thought that this was important enough to post so EVERYONE would be aware of how SMALL of an amount of laser radiation has the POTENTIAL to do damage to your precious eyesight! So, PLEASE, for your own peace of mind, PROTECT YOUR PRECIOUS EYES! You only have two, & there ain't no more! phoenix77/rob :cool:
I think that's maximum amount that you can safely look into for a prolonged period of time without damaging your eyes. For a brief accidental exposure 5mw is considered safe because your blink reflex will protect save your eyes in time.
 
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5mW passed over the eye wont do any damage, but if it was held in the same spot in the same part of your eye it would cause some pretty bad damage.(hypothetical, and it would have to be for like hours...)
 
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Laser protection is determined based on exposure time. 5mW is considered "safe" for exposures of 0.25 seconds which is the blink reflex. Prolonged exposure to 5mW is dangerous without eyewear. You will damage your eyes looking into a 5mW laser if you do not allow your eyelids to close. When you figure exposure, the calculation is determined by four time periods: 0.25sec, 10sec, 600sec, and 30000sec. These times correspond to: blink reflex, accidental exposure (relating to eye motion in the near infra red), diffuse exposure during activities such as alignment, and finally full working day for those who work with lasers during working hours. The levels you can be exposed to and the OD rating of glasses varies based on your exposure time and intensity.

So in reality, there is no "safe" level for exposure but the responsible person makes every attempt to mitigate any potential exposure with appropriate eyewear. Generally for the hobbyist the 0.25 sec and the 10 sec exposure limits should be followed. When I recommend a pair of protective lenses the OD is based on attenuation to <5mW for a direct exposure allowing the blink reflex to mitigate the 5mW exposure. The lenses are designed for 10 sec direct exposure. Frankly, I think 5mW exposure is too high but hobbyists vapor lock if they cannot see the beam.

ANSI Z136 is the standard if you are interested in exposure limits and is what is enforced by OSHA.

And here you guys thought you were in a hobby where you were free, when in reality you are knee deep in a multitude of laws and regulations.
 

Zom-B

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daguin said:
[quote author=Zom-B link=1217088543/0#3 date=1217103881]When looking at the spot (eg when burning stuff) then multiple factors play a role; beam spot size, duration, color and ambient light.
Another trick to lower the risk is to not look directly at the spot, but at various points around it. This keeps the spot moving on your retina so it doesn't stay in one place for a longer time.
For example (guesses from experience) in a semi-dark room, and using my trick:
240mW red is safe when focused to a sharp point, for 10-15 seconds
200mW blue-ray is safe when focused to a sharp point, for only a couple of seconds, because the color is much less bright and the iris does not shrink.

These ideas/recommendations are [highlight]NOT [/highlight]safe! Laser light takes [highlight]less than a second[/highlight] to burn the retina!!!!!!! Damage can happen before you can blink

Zom-B, at the powers you are playing with, you should be much more careful AND familiarize yourself with both the dangers of laser light and proper safety practices. A burn across your retina would be problematic. Blind spots would be a pain in the A**. An unlucky burn across your optic nerve would change the course of your life forever.

As Petrovski said, 405nm is NOT safer. If anything it is more dangerous. NOT because it is brighter, but because it appears dimmer. 200mW of green laser light LOOKS bright and dangerous, so you have the tendency to be more careful. 200mW of blu-ray laser light doesn't LOOK as bright, so the tendency is to relax your watchfulness.

You only get two chances!

Peace,
dave[/quote]
I think you (petrovsky, daguin) are misinterpreting my advice. I indirectly said UV is MORE dangerous because it is dimmer and not the other way around, by stating that only less seconds exposure is still safe. By being focused to a tiny point, in mean, that you shine the laser at something burnable and look at THAT, not looking INTO the laser of course. And indeed, real safety cannot be achieved by tricks, but these tricks do improve the safety (and never reduce) in absence of 'real' safety (eg. goggles). I have thoroughly studied laser safety precautions in the past so I think I know what I'm talking about. Just to name one other safety precaution, never wear reflective jewelry when operating lasers.
 

daguin

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Zom-B said:
I think you (petrovsky, daguin) are misinterpreting my advice. I indirectly said UV is MORE dangerous because it is dimmer and not the other way around, by stating that only less seconds exposure is still safe. By being focused to a tiny point, in mean, that you shine the laser at something burnable and look at THAT, not looking INTO the laser of course. And indeed, real safety cannot be achieved by tricks, but these tricks do improve the safety (and never reduce) in absence of 'real' safety (eg. goggles). I have thoroughly studied laser safety precautions in the past so I think I know what I'm talking about. Just to name one other safety precaution, never wear reflective jewelry when operating lasers.

I think you need to re-read your post with a more critical eye. In my field, we speak of the "message outcome." Your intentions are not as important as the message created in the minds of the audience. Your post leaves the audience, especially young, naive, broke members of the audience with the impression that they can protect themselves from eye damage by by "moving their eyes around" and making decisions about "brightness' in a dark room. If you truly believe these things, you are in for trouble. If you do not, then you need to retract this so that the naive will not believe that this is a way to protect their eyesight.

You have focused on the difference in statements about 405nm. These statements were extensions on safety. You avoid the more important aspect that your recommendations on how to protect your eyes, without laser goggles, are wrong and dangerous. The audience is left with permission NOT to spend their money on laser goggles.

If you truly believe that you can "protect" your eyes from 180mW of 405nm light by "not focusing on the dot", you are slowly destroying your eyesight. A catastrophic burn of the optic nerve is NOT the only eye damage inherent in laser light. Blind spots that gradually destroy your eyesight are a real and present danger. All moving your eye around does is spread out the damage and increase the chance that the optic nerve will be hit.

Peace,
dave
 




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