Class 4 Laser Safety

Hey guys,

I am fairly new to lasers and am still learning about how to be safe with them.

At my college I am working with a team on a project where we are using a Class 4 laser.

My teammates think that the reflection from a Class 4 is not dangerous, however I disagree from what I have read and feel very uncomfortable with their actions.

Today, they were testing the laser and there were a few moments where I saw the reflected beam for nothing more than a second or two. This in and of itself raises concern.

How do I know if there is any damage to my eye from the reflected beam?

I'm not sure if it was a matte surface or a reflective surface. I didn't stare at it to find out.

Any help and insight is greatly appreciated. I care about my eyes and I don't want dummies at school ruining them.

Thanks again

Where was the professor/instructor during all this? I would imagine a safety officer would need to be present when a dangerous laser is to be used by students.

Only a doctor can tell if there is damage done after the fact. We can only tell you if there is damage if it is blatantly obvious. If you see afterimages or color bleaching or spots or blurry sections or wave sections or anything else liek that go see a doctor, major damage has been done. only the first two symptoms I listed will heal and they may take quite some time.

There's plenty of posts and threads about laser safety on the forum, heck I wrote one that got stickied. Do some reading and shield your eyes from idiots with lasers.

Depends on wavelength too. What type of laser was it?

To give an accurate answer the laser type, power and surfaces involed are important.

Was the laser between 400 and 700nm?
Yes

Did you see a very bright flash and after images?
Yes

Do you still have weird parts in your vision?
Yes:

Damage has been done, go see an eye doctor immediately

Click to expand...

No:

I'd say just to be sure check with an eye doctor. Hold the college responsible for the costs if they haven't given safety instruction. If they did hold you teammates responsible, they should know better in any case.

Click to expand...

Click to expand...

No:

You're fine, if you're hit with a class 4 visible laser you see more than just a dot that dissapears quite fast.

Click to expand...

Click to expand...

No:

There is no way to be sure what happened. I'd say just to be sure check with an eye doctor. Hold the college responsible for the costs if they haven't given safety instruction. If they did hold you teammates responsible, they should know better in any case.

Click to expand...

A LOT depends on the material the laser was shining on, if it was a white piece of paper there is most likely no damage at all. Shiny surfaces are definitely very dangerous.

In any case, class 4 lasers demand a LOT of respect, report this to the college immediately as this is unacceptable behaviour.

Good news guys,

I just visited the eye doctor and he took images of my retinas to verify that there was no damage.

Lucky for me the eye doctor verified and assured that I have no damage in either eye.

My teammates are not very smart and I need to have a serious chat with them. Apparently the one member on our team who is in charge of the Class 4 laser doesn't believe that diffuse or reflection of the beam can cause harm.

To make things even more scary, he is using reflective tape to try and make the laser more detectable by a photo diode. This is what raised a lot of my concern since he was using reflective tape!

After I was exposed a few times I immediately developed a headache. Thus, I went to the eye doctor out of concern for my own eyes!

Again, I am happy to say I'm in the clear according to the eye doctor. Thank goodness too! This is scary stuff guys.

I really hope I don't have to deal with something like this again. In fact it scares me people can even own these kind of lasers. It should be illegal for idiots to operate these kind of lasers.

As for the wavelength in nm... I'm not sure. I just know it's a 1000 mW laser and was being used to shine at reflective tape.

To be honest I'm scared to be around my team now... My teammates didn't seem to believe there was danger either. I'm afraid they will do it again!

Forestman said:

They should be against the law!

Click to expand...

:barf:

Forestman said:

In fact it scares me idiots can even own these kind of lasers. They (idiots) should be against the law!

Click to expand...

Fixed for you.

Anything can be dangerous in the hands of an idiot. No reason to make lasers illegal, just make sure idiots can't get their hands on them is all.

Forestman said:

Good news guys,

I just visited the eye doctor and he took images of my retinas to verify that there was no damage.

Lucky for me the eye doctor verified and assured that I have no damage in either eye.

My teammates are not very smart and I need to have a serious chat with them. Apparently the one member on our team who is in charge of the Class 4 laser doesn't believe that diffuse or reflection of the beam can cause harm.

To make things even more scary, he is using reflective tape to try and make the laser more detectable by a photo diode. This is what raised a lot of my concern since he was using reflective tape!

After I was exposed a few times I immediately developed a headache. Thus, I went to the eye doctor out of concern for my own eyes!

Again, I am happy to say I'm in the clear according to the eye doctor. Thank goodness too! This is scary stuff guys.

I really hope I don't have to deal with something like this again. In fact it scares me people can even own these kind of lasers. They should be against the law!

As for the wavelength in nm... I'm not sure. I just know it's a 1000 mW laser and was being used to shine at reflective tape.

To be honest I'm scared to be around my team now... My teammates didn't seem to believe there was danger either. I'm afraid they will do it again!

Click to expand...

Good to hear you are ok! Class 4 is 500mW (for CW lasers) and beyond, that's the highest class.

My advice: wear appropriate laser safety eyewear, that should protect you in case of a direct hit. Be REALLY careful when working with such a powerful laser, even a direct reflection of a photodiode could burn stuff and certainly burn a retina. That AND laser safety eyewear of course. The college should be able to provide them. Here in the Netherlands any class 3b laser (and thus certainly a class 4) should be behind a door with warning lights and some sort of lock or interlock system.

The other option is not to be in the same room as the laser. I wouldn't take chances with a powerful laser. If you really want to have fun you can report the college to the regulating agencies, it sounds like the college isn't take care of the safety of the students.

Ya, I agree with Bluefan. But personally I would just buy my own pair of safety glasses and encourage my class mates to buy some as well.

For the origional poster.. Where is your prof and the laser safety officer? The call is NOT made by your group mates, its made by the Prof and the LSO, or a postdoc. Occupational safety and health is their perview. The fact that you had to come on line to seek advice worries me. I've made a career of working with industral and university lasers, as well as laser shows. Something is wrong if you were not briefed correctly prior to entry of the laser lab.


Join Linked-In, find the laser safety professionals group. Ask questions.
This is not for everyone, as most hobby laser questions can be answered here. At a college, odds are, this it is a pulsed laser that is well beyound the scope of this site. The linked in group can answer detailed questions about fast pulsed lasers.

The only way to find out if a laser exposure is dangerous is to measure. There is no guessing, and even if it is outside the range of corneal transmission, that just means the cornea gets damaged instead of the reina.

Try to find one of the more recent laser safety books by Dr. David Sliney.



Steve

geekypyro21 said:

Ya, I agree with Bluefan. But personally I would just buy my own pair of safety glasses and encourage my class mates to buy some as well.

Click to expand...

If he works in a workplace or educational environment, is the responsibility of his employer to buy protective gear. It sets a slippery slope to expect a student to pay for a 400$ pair of OSHA approved goggles.

Steve

What country is he in? Maybe they don't have any rules, laws or guidelines at the school he is attending. You need to find out more info on the laser and get some goggles to protect yourself. They might even have them available at your school. You need to talk to your professor about your concerns and if he doesn't deal with it satisfactorily go to the dean.

I want to thank you all for your information and replying.

I have one more question concerning the Class 4 Laser.

It has the ability to turn down the power, which was done to do a short presentation with the project it was being integrated with. The power was turned down to about 50 mW and was being shined onto a surface that diffused the laser beam.

So my question is, can the 50 mW laser cause retinal damage from a diffuse reflection?

Thanks again for the help!

From a diffuse reflection, no.

InfinitusEquitas said:

From a diffuse reflection, no.

Click to expand...

Wow thanks for the quick reply!

Glad to know all is well then. There were a lot of eyes looking at it.

Just out of curiosity, what power would be required to cause danger with diffused reflection?

Impossible to answer that question. It would depend on the material the the laser beam is terminating on.

Personally I haven't been able to get either of my LPM's to register a diffuse reflection off of common household stuff that's matte from further than a few inches with a ~1.5W laser. (Obviously not a very scientific test.)