What can I do till I get glasses

Youre fine to use it indoors, just stay away from reflective objects. Lots of things carry the risk of physical injury or incapacitation including driving, guns, stoves, fireworks, motorcycles, swimming, dogs, etc... as long as you exercise due caution, you should be fine. What is the point of owning a laser if you cant enjoy the beauty of it? At 90mw, diffuse reflections even off of white surfaces are not harmful at normal distances one might encounter while inside. There are a lot of people here who would have you think differently, but the math doesnt lie. There simply is not enough energy reflected back to harm you. However, with close up burning, goggles would be the smart bet.

Class 4 lasers, however, pose a risk because the amount of energy reflected in any given direction can pass the threshold of safety within a certain distance.

People also grossly overstate the damage cause by lasers. Eye damage is no joke, but you will not go totally blind from a quick reflection or even a quick direct hit from a laser. Lasers cause small blind spots where the beam was focused onto your retina, destroying the cells that received the energy. This is definitely a serious matter, because the blind spot could happen in the center of your vision, severely disrupting it, but it will not cause ::boom:: instant black blindness as some would have you think.

Just enjoy your laser, and keep it away from anything that is shiny or living. Wear your goggles when there is a realistic risk of reflection or direct hit, and while burning. But, of course, this is my philosophy after weighing risks and benefits. Do whatever makes you comfortable.

FarewellToKings said:

People also grossly overstate the damage cause by lasers. Eye damage is no joke, but you will not go totally blind from a quick reflection or even a quick direct hit from a laser. Lasers cause small blind spots where the beam was focused onto your retina, destroying the cells that received the energy. This is definitely a serious matter, because the blind spot could happen in the center of your vision, severely disrupting it, but it will not cause ::boom:: instant black blindness as some would have you think.

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What exactly are you saying? That somehow partial permanent blindness is an acceptable situation compared to total blindness? That this does not warrant the same level of caution and protection?

Stop spreading such ignorant bullshit.

Bionic-Badger said:

What exactly are you saying? That somehow partial permanent blindness is an acceptable situation compared to total blindness? That this does not warrant the same level of caution and protection?

Stop spreading such ignorant bullshit.

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Youre calling my post ignorant because I am clarifying what actually happens with laser eye damage? Gtfo. Its important to know what really happens, and to clear up misinformation for people who know nothing of lasers. To tell them they are going to go totally blind at the smallest mishap is stupid and irresponsible. The best thing to do is educate.

I just want to come in here to say NEVER SHINE ON STREET SIGNS EVEN WITH 20-40mw LASERS. The reflection can come back rather focused. I almost got hit right in the eye by one and that was from 30 feet away or so.

FarewellToKings said:

Youre calling my post ignorant because I am clarifying what actually happens with laser eye damage? Gtfo. Its important to know what really happens, and to clear up misinformation for people who know nothing of lasers. To tell them they are going to go totally blind at the smallest mishap is stupid and irresponsible. The best thing to do is educate.

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You missed the point that eye damage is irreversible and will never be able to be fixed. Your eyes are very important in daily live, that's why safety is so much stressed. In most cases you won't be instantly blind (although a 0.4J shot to you blind spot does exactly that), damage in your central vision doesn't require much to take out chunks of the most sensitive and important part of the retina. It's a real danger, a simple stray beam of light may just be of high enough power to have a huge impact in your life. There are examples of this.

FarewellToKings said:

Youre calling my post ignorant because I am clarifying what actually happens with laser eye damage? Gtfo. Its important to know what really happens, and to clear up misinformation for people who know nothing of lasers. To tell them they are going to go totally blind at the smallest mishap is stupid and irresponsible. The best thing to do is educate.

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You are being stupid and irresponsible by creating a false sense of security in people about the dangers of lasers to the eyes. It's like telling people that, oh you don't have to be as cautious about falling off a 5-storey building compared to a 20-storey building; sure, you'll only have most of your bones shattered and possibly be paralyzed, but at least you're not dead. You're not educating; you're diluting the importance of safety around dangerous lasers.

The bottom line is: with Class IIIb lasers the smallest mishap can result in permanent blindness. Whether this is partial or total does not matter; neither is desirable, and both should be avoided in all cases.

I can see where both of you are coming from, I agree with farewelltokings in that no, a 15mW laser mishap isn't going to make your eye explode
BB has a good point though, kids don't seem to understand that the damage is cumulative, it is better to think a laser will blow your eyeball up than it is to say; "Yeah, if you are careful, you should be fine"
When I was young, LiPo batteries were first coming out and the manual read like they had nitroglycerin in them.
I didn't know any better but didn't want my house to explode so I took them back and bought Nimh batts instead.
Saying these lasers are dangerous is like saying all LiPo batteries are too.
Accidents happen every day but handled properly both are generally harmless.

I'd add license plates to the group of street signs as well. I tested them with my 1mW red a few years ago.

AUTO XX said:

I can see where both of you are coming from, I agree with farewelltokings in that no, a 15mW laser mishap isn't going to make your eye explode
BB has a good point though, kids don't seem to understand that the damage is cumulative, it is better to think a laser will blow your eyeball up than it is to say; "Yeah, if you are careful, you should be fine"
When I was young, LiPo batteries were first coming out and the manual read like they had nitroglycerin in them.
I didn't know any better but didn't want my house to explode so I took them back and bought Nimh batts instead.
Saying these lasers are dangerous is like saying all LiPo batteries are too.
Accidents happen every day but handled properly both are generally harmless.

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Your anecdotal analogy is flawed. There is a major difference between the zealous warning signs on a LiPo battery and those on a Class 3b laser. While you are able to mistreat a LiPo battery for some time before they explode or cause some other malfunction, you get no such grace period with your eyes. The warning signs on a LiPo battery are more like the Class 3r/a (< 5mW) laser pointers warnings, where if you maintain longer term exposure, then permanent damage may occur. Yeah, you have some time on those. That's why they're laser pointers and legally safe for public use.

No such condition exists with Class 3b lasers. Such lasers are powerful enough that the speed of your blink reflex is not enough to protect your eyes. That means a sweep across your eye can cause damage. There are so many gradations of laser power at lower levels because the amount of laser light to cause permanent eye damage is very low. In fact, Class 2 lasers are supposed to be the "laser pointer" power level (~2mW), but reds looked so weak that the limits were pushed. Ever think about that? 5mW isn't much power, and yet is the threshold between safe and unsafe power levels.

Unfortunately, people seem to not understand what these classifications imply and rather take the stupid path of "LOL! My laser is just 10mW, only 5mW above the limit. That's nothing." Then you get hit in the eye and realize just how much brighter the laser looks up close. Then you have a nice little blurry region in your eye that you notice under certain conditions. No, not a big hole, but it's there, and a permanent fixture on your eye.

How powerful is the beam of a 100mw ~4km far? Is that still dangerous to the eye (on the receiving end). Could I try with a mate if the beam is visible? (I can see the dot that far.)

The light will be spread out over such wide a "dot" that the amount of light that hits the eye will be below the safety limit.
I doubt he will be able to see the beam, but the "dot" should look pretty cool.
It will be a large illuminated area with sharp edges.

With a 1mrad divergence (pertty low) it will be a 4 meter area. It definately won't have sharp edges though.

Will I be able to see a faint dot of the laser or nothing at all with the googles? I saw some youtube videos and it seems to be blocking it completely. All red safety goggles work like that or some are better than others?

Mine are ~O.D. 4 and they let me see the dot quite well.
I can honestly say it is easier to best focus the laser with goggles, even a red laser over 20' away is difficult without 'em.
The dot appears orange with my 445 (blue) but that depends on the type of glasses you get.

Is it a lab style laser that you used a home made driver for? Because if that is the case, just drive it with less current until you get the glasses

You may find these links useful.

Divergence Calculator - Safe Lasers - Laser safety information, tools, and free warning labels.

Hazard Distance Calculator - Safe Lasers - Laser safety information, tools, and free warning labels.