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You think lasers are a for fun?

AUTO XX

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Lasers are GREAT for your eyes!
I had mine done a week ago and I don't have to wear glasses anymore YAAY!
I also think that my 445 was stolen out of my truck, hope the dick blinds himself
:lasergun:
 



RyanElectro

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Lasers are GREAT for your eyes!
I had mine done a week ago and I don't have to wear glasses anymore YAAY!
I also think that my 445 was stolen out of my truck, hope the dick blinds himself
:lasergun:
haha, what percentage correction did you get? My mom got hers back in 2003 at 80% correction and 3 years later she had to wear reading glasses lol.

And I'm surprised someone would steal a laser, I would think most people would just mistake it as a flashlight haha
 

fixitiwill

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Ryanrenesis:
The damage done to my vision was done when I was looking at the spot that my lasers make. I figured that since the spots in my vision disappeared after a while (like the spots you get after looking at the sun) that they were just a temporary issue. I was wrong, but it wasn't really obvious until much later. Cumulative damage, it's a bitch!
 

AUTO XX

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Uh, I don't know the correction.
I was:
-2.75 right
-3.75 left
And a .5 diopter astigmatism in one eye (I think left)
I'm still having great fun with dry eye but when they are working properly (I cheated a bit in the eye exam and used drops) they are both 20/15.
Hopefully this going fuzzy nonsense quits in a week or so, makes it hard to see stuff when I'm milling.
The lathe now has a DRO (cheap off ebay ^_^) so I can go by measurements but the mill is full manual :(
 

RyanElectro

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Ryanrenesis:
The damage done to my vision was done when I was looking at the spot that my lasers make. I figured that since the spots in my vision disappeared after a while (like the spots you get after looking at the sun) that they were just a temporary issue. I was wrong, but it wasn't really obvious until much later. Cumulative damage, it's a bitch!
Oh my god, that is scary. You were using a 445nm laser at >1W over time with no goggles that's what damaged your eyes? Man, I'm going to make sure I always wear my goggles whenever I set the focus indoors damn.

Uh, I don't know the correction.
I was:
-2.75 right
-3.75 left
And a .5 diopter astigmatism in one eye (I think left)
I'm still having great fun with dry eye but when they are working properly (I cheated a bit in the eye exam and used drops) they are both 20/15.
Hopefully this going fuzzy nonsense quits in a week or so, makes it hard to see stuff when I'm milling.
The lathe now has a DRO (cheap off ebay ^_^) so I can go by measurements but the mill is full manual :(
Oh my mother had astigmatism too, but on both eyes. She was bedridden for like a week though I remember how much pain she went through in the healing process. I don't know if that has changed over the years lol
 

AUTO XX

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The day after surgery I was out in the sun all damn day!
I drove to get the check up, drove over to KFC (I never eat junk food), I was having fun making "flirty eyes" with a girl there (she left me her number but I have a gf) while she waited for her food to go, went to a nearby mall and browsed there for a couple hours, made a couple new friends, you know... Good stuff.
The next day I payed dearly :(
My eyes were VERY light sensitive, I wore swimming goggles all day because they were so dry, it was pretty annoying.
It got better after that but they go fuzzy if I'm on the computer or (like now) doing my taxes :rolleyes:
 

anuragwap

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This (scary) thread ruined any chance of buying 5+mW lasers for me, I'll rather stick with LEDs (that too w/o collimating optics)! Was planning to buy some Royal Blue Rebel ES, I have to think again after reading this thread.

As a newbie, I can't really see the point in buying high power lasers and then using goggles to reduce the brightness of the dot to a 5mW one! (except for burning stuffs and impressing other people)
 
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Tech_Junkie

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If you watch out where you point it, the beam of a high watt laser is extremely beautiful outside.
 

tsteele93

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This (scary) thread ruined any chance of buying 5+mW lasers for me, I'll rather stick with LEDs (that too w/o collimating optics)! Was planning to buy some Royal Blue Rebel ES, I have to think again after reading this thread.

As a newbie, I can't really see the point in buying high power lasers and then using goggles to reduce the brightness of the dot to a 5mW one! (except for burning stuffs and impressing other people)
That is true, the goggles pretty much take most of the fun out of a high power laser.

If you do a a search, there are some posts with Sony's safety specifications and the general idea is that DIFFUSE viewing of a dot under 500mW is going to be safe.

Looking at that data, combined with a couple of other facts - like how many members here admit to not using goggles properly, and the fact that you can buy 50mW lasers ALL DAY LONG on eBay and Amazon for less than $10 and I have to believe that 50mW is safer than it seems at first glance.

Considering all of that, I tend to see a 50mW laser as something you should be respectful of, but not have to wear goggles with all of the time.

I PERSONALLY think that line is maybe even somewhere higher between 50mW and 500mW.

For me, 500mW is where things get very serious and you will never see me indoors with a 500mW or greater without safety goggles.

As tech junkie says, OUTDOORS with proper respect and care, you,can responsibly use greater than 500mW lasers goggles.

I don't want you to be casual about lasers, but I hate to see you scared of even some of the lower power (50-150mW) lasers that most of us here use responsibly but casually with respect, but not with FEAR.

Feel free to start with 5mW - a green 5mW is plenty bright, but keep your mind open to growing within the hobby.
 

nsptxxfh

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Hello everyone.

From a strictly physical/biological point of view, any continuous beam in the visible spectrum that enters your eye with more than a few mW of power will cause direct thermal injury in less than 1 second. The extend of the injury will of course depend on multiple factors (power, wavelength, exposure duration, etc.) so it can be difficult to pinpoint a specific power. I would not hesitate to call this "settled science".

Photochemical injury can also occur with diffuse beam (more dangerous at shorter wavelengths). The calculations are pretty simple, but one does need to have a copy of the relevant safety standard, a scientific calculator and an idea of the likely exposure conditions.

The calculations made with the standards (Z136.1 and IEC 60825-1) are based on real experiments (done on animals, adjusted for humans) and I would tend to trust them. That's why I would recommend goggles for class 3B and class 4 lasers.

Now, in practice, the probability or the extent of an injury could be reduced. For example, if exposure conditions make it so that the entire power a specific laser beam will not enter you eye (or that the exposure is really short if the beam is moving). It's also possible that a small injury could go unnoticed (the brain does do wonders). Theses factors probably contribute to the impressions that lasers are safer than the warnings seem to indicate. I think that relying on luck to protect you is not a good idea.

I should point out that I may have a different perspective in this "debate" because I do not use laser as a hobby but for my work. I personally think that my work should not physically harm me, but I admit that the level of risk that one is willing to accept could be higher in the case of a hobby. Although I would personally not recommend taking risks with your eyes. They will not heal following an injury.

Best regards
 

tsteele93

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Hello everyone.

From a strictly physical/biological point of view, any continuous beam in the visible spectrum that enters your eye with more than a few mW of power will cause direct thermal injury in less than 1 second. The extend of the injury will of course depend on multiple factors (power, wavelength, exposure duration, etc.) so it can be difficult to pinpoint a specific power. I would not hesitate to call this "settled science".

Photochemical injury can also occur with diffuse beam (more dangerous at shorter wavelengths). The calculations are pretty simple, but one does need to have a copy of the relevant safety standard, a scientific calculator and an idea of the likely exposure conditions.

The calculations made with the standards (Z136.1 and IEC 60825-1) are based on real experiments (done on animals, adjusted for humans) and I would tend to trust them. That's why I would recommend goggles for class 3B and class 4 lasers.

Now, in practice, the probability or the extent of an injury could be reduced. For example, if exposure conditions make it so that the entire power a specific laser beam will not enter you eye (or that the exposure is really short if the beam is moving). It's also possible that a small injury could go unnoticed (the brain does do wonders). Theses factors probably contribute to the impressions that lasers are safer than the warnings seem to indicate. I think that relying on luck to protect you is not a good idea.

I should point out that I may have a different perspective in this "debate" because I do not use laser as a hobby but for my work. I personally think that my work should not physically harm me, but I admit that the level of risk that one is willing to accept could be higher in the case of a hobby. Although I would personally not recommend taking risks with your eyes. They will not heal following an injury.

Best regards
First, let me address your closing statement.

Eyes DO heal after an injury. It depends on the type and level of injury how well they will heal.

Rapid Healing of Laser Eye Injuries with Light Emitting Diode Technology

That is an interesting document that suggests that near-ir light may accelerate the healing.

There are other documents that show methods being studied to accelerate healing with growth hormone therapy.

Accelerated Healing of Laser-Injured Rabbit Retina by Basic Fibroblast Growth Factor

Furthermore, we know that a great deal of the lasers markets as <5mW are actually well into the 50mW (and higher, especially violet) range and there has not been a huge influx of laser-related eye injury, then you have to assume the FDA built in a safety factor of probably 10.

Here is a very good article on laser injuries...

So far, the reports have been scattered and anecdotal...

"At the American Academy of Ophthalmology, a spokeswoman said the group was unaware of any increase in eye injuries caused by lasers. But doctors interviewed for this article said they were shocked by the easy availability of high-powered lasers."

There is no doubt you should be using goggles for high wattage lasers. But I strongly suspect there isn't a person on here using goggles for a 50mW laser and most members are careful, but without goggles when shining higher wattage lasers outdoors for viewing beams or stargazing.

Using goggles on a 50mW beam would make it virtually invisible.

I'm not sure where the real-world line should be drawn. We all recommend goggles to anyone getting a >5mW laser for legal issues and to try and stress the importance of laser safety, but very few members really practice safety to the fullest extent.

I guess each person has to decide what they are comfortable with. I hear of members who carry around 2 watt blue lasers on a daily basis. I wouldn't be comfortable with that. I am comfortable with a 200mW green used cautiously and I almost always have my 50mW green with me because at a relatively safe wattage, it still has a pretty good wow factor.
 
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nsptxxfh

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tsteele93 :

The eyes can heal in some circumstances. But that is probably the case only when cells are not destroyed by the laser (inflammation, bleeding, etc.) In other words, the disruption around the blind spot might go away, but the fried cells will still be dead. (To be clear, I agree with you that most low power laser injuries will not necessarily result in catastrophic eye injury and that some of the initial "damage" will go away in the following weeks/months.)

As you say, green lasers without appropriate filters can have a much higher power than what is advertised or visible. In theory, selling a laser as a 5 mW but with a higher power is illegal. All commercial lasers are required by the FDA to have the MAXIMUM power displayed, regardless of the wavelength (although the wavelengths should also be displayed).

That fact that there are few reported injuries does not mean that they do not happen. The scientific papers rarely report laser eye injuries anymore (because there's nothing new to say about it). (For example, there where more than 10 laser eye injuries in my university in the last 10-15 years. None of them were the subject of papers, not even articles in the local press.)

I would think that the absence of injury reports comes more from the fact that people probably don't want to talk about those (maybe minor) injuries and the fact that, as other people mentioned already, it is probably well known that you need to manipulate high powered lasers with respect (greater than 5 mW).

The safety factor is 10 for most maximum permissible exposure (MPE) calculations in the standards. For example, a 532 nm, continuous laser has a MPE that corresponds to a 1 mW of power entering the eye for 1/4 of a second. Meaning that around 10 mW of power into the eye for 1/4 s will result in an injury visible upon medical examination in around 50% of the exposures. A lower power will reduce the probability of injury and higher power will guaranty it. The limit of 5 mW (for class 3A-3R) lasers is there for that reason : a direct -accidental- hit with the full power of a laser in the 1-5 mW range might not cause an injury. So for professional use ("educated about the possible consequences of exposure"), eye protection might not be necessary (depending, of course, on what you actually do with the laser).

That being said. It's not because are exposed to the direct beam of a 50 mW laser that more than 5-10 mW will enter you eye and cause an injury. The beam diameter might be to big to let all of its power into you eye, the beam might not stay in one point on your retina long enough to cause injury, etc.

Safety glasses have to be selected for each laser depending on its power and wavelength. The purpose is to reduce the power below the MPE (about 1 mW if we use the CW 532 nm example again). If you use OD 3 glasses for a 50 mW laser, you will, as you say, be disappointed by the brightness. (You could also be disappointed even with the correct glasses, since you can't have both 100% safety and high power at the same time.)

I agreed with what I think is the basic message of your post : you have to be careful about how you use your laser, and that each person has to decide what level of risk they want to take. My point was that, from a strictly physical/biological point of view, the limit of what is or isn't dangerous is clearly known. You have to be aware of those limits when you make the decision to not wear safety glasses.

Finally, as I said before, I use laser in my work and would never work without glasses for class 3B or class 4 lasers. I will also wear glasses for class 3A/3R, depend of the application. Now, using lasers for fun is another thing entirely (part of the pleasure, I imagine, comes from the high power).

P.S. The potential for chronic injury (following multiple, long exposure to the diffuse reflection (spot) of a high power class 3B or class 4 laser, for example), as the OP pointed out, should not be neglected. (And the examples of calculations I gave are not valid in those cases.) It is particularly dangerous because it's more likely to affect the macula of both eyes and the damage is cumulative.
 
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Seoul_lasers

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Its not rocket science, own the right glasses and wear them when you need to.

I rarely use glasses because im always in the open when i use my laser, kinda hard to reflect off of something when im pointing down from flat roofs .

I dont use my laser inside, does nothing for me, i get to work at night or early mornings whenever i want to, so im on empty commercial / industrial sites by myself alot in the a.m.
Own glasses or leave, maybe
Use glasses all the time or leave, just stupid
You can still flash blind yourself off of scattered laser light from smoke. IT might be diffused enough not to cause permanent eye damage, but it's still risky. Also, when using the higher powered blue wavelength pointers, they pose an addition blue-light hazard that can trigger damage to the retina. Using glasses around these Should be a NO-BRAINER.
 

LSRFAQ

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Fixitiwill,

Thank you for having the sheer courage or "balls" to come forward and tell your story. It needs to be heard!



Steve
 

fixitiwill

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You get to the main point of my post with the following statement nsptxxfh:
The potential for chronic injury (following multiple, long exposure to the diffuse reflection (spot) of a high power class 3B or class 4 laser, for example), as the OP pointed out, should not be neglected. (And the examples of calculations I gave are not valid in those cases.) It is particularly dangerous because it's more likely to affect the macula of both eyes and the damage is cumulative.
I don't think too many people dispute the fact that direct laser exposure can cause damage. It is the diffuse and specular reflections that are a bit more subtle.
 




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