Lasers & Eyes

corpse108 · Oct 14, 2008

Hi. I have a couple of questions.

Where can I find Safety Glasses? I'm having a hard time locating a site that sells them.

I saw the formula to calculate the correct OD but how do I find out the reduction factor of the laser? Does the Class of the laser have anything to do with this?

Thanks,
Josh

daguin · Oct 14, 2008

corpse108 said:
Hi. I have a couple of questions.
Where can I find [highlight]Safety Glasses?[/highlight] I'm having a hard time locating a site that sells them.
I saw the formula to calculate the correct OD but how do I find out the reduction factor of the laser? Does the Class of the laser have anything to do with this?
Thanks,
Josh

Try searching "laser goggles" instead.

Peace,
dave

corpse108 · Oct 16, 2008

Okay so the reduction factor is how much laser light the goggles block? Now how do I figure out how much light the laser puts out and how strong of a factor it takes to block it? I read somewhere that if you can see the laser with the goggles they are not strong enough.

corpse108 · Oct 30, 2008

I found out. It is in the OD Post if anyone else is wondering and its very thorough.

Snytbaggen · Nov 20, 2008

A friend was here today and found my DX30 and started to play with it. I went upstairs and when I came down again he was shining it out of the window. I looked at the wall opposite of the window and didn't even know he was shining, since he was still in my room. I see a pretty large green blob floating around on the wall and barely had any time to react when BAM! right in my left eye. My eye seemed fine, however and I wasn't blinded or didn't see any spot. The hit was on the side of the eye, though, so is there any possibility that some damage occurred that I'm not aware of?

If my math serves me right, and if it's true that a reflection of a window is 5-10% of the original power I would have gotten around 1,5-3mW in my eye, spread out to a pretty large area. Is this correct?

lightfoot500 · Dec 2, 2008

Definitely a MUST Read!
this thread is very helpful, lucky i started out with a 5mw.
may i suggest the senior members put together a document on proper use of lasers as far as the eyes are concerned. i am a newbie here so i wouldnt be the one to do it.

Antracith · Dec 10, 2008

Ok, I read this thread for the first time today and I got really scared!

I Have been playing around alot with my 50 mW dx laser and my 270 mW red DIY laser and I have gotten reflections from mirrors straight into my eye several times already. I must have been lucky caus I have still not experienced any sight degradation.

Is green the most dangerous? I mean, is a green 50 mW worse than a red on 270 mW? Is there good glasses that can protect me good from both green, red and violet? I am really gonna get myself a pair of gogles now. As a matter of fact, I am blind on my left eye because of a sickness called coates disease so I really don't wanna hurt my other eye...

Great thread btw!

StrictlyBudget · Dec 10, 2008

Antracith said:
Ok, I read this thread for the first time today and I got really scared!

I Have been playing around alot with my 50 mW dx laser and my 270 mW red DIY laser and I have gotten reflections from mirrors straight into my eye several times already. I must have been lucky caus I have still not experienced any sight degradation.

Is green the most dangerous? I mean, is a green 50 mW worse than a red on 270 mW? Is there good glasses that can protect me good from both green, red and violet? I am really gonna get myself a pair of gogles now. As a matter of fact, I am blind on my left eye because of a sickness called coates disease so I really don't wanna hurt my other eye...

Great thread btw!

all i can say is, you're not responsbile enough to handle a laser pointer. come on! the first time you got hit in your eyes, you should have been running to your computer to order a laser goggle. :-/

i think the more visible the laser is, like Green, the more the damage will be on the retina (the part that gives you colour vision). it might also damage the other components of your eye like the cornea. for an invisible laser, it might damage all the components of your eye but it won't damage your retina. also, it is harder to notice the damage in your vision unless you go for a check up for the case of an invisible laser. am i right?

FrothyChimp · Dec 10, 2008

Any high enough power of any visible wavelength and near UV as well as near IR will damage your retina the same. All these wavelengths will be focused by the cornea and lens onto the retina. So mW for mW or W for W you do the same damage. There is no preference based on wavelength.

The UV region and mid-IR and far-IR is another story. UV will cataract your lens never making it to the retina. Mid-IR will show signs of retinal damage and corneal/lens damage whereas far-IR will damage the cornea and lens exclusively.

Cyparagon · Dec 10, 2008

Your retina is red. Therefore, more red is required to burn it than green.

FrothyChimp · Dec 10, 2008

Not true. The retina is clear. The red coloring comes from the blood vessels in the choroid layer below the retina. So, the laser light always passes through the retina doing whatever damage is to be done before passing to the vasculature.

StrictlyBudget · Dec 10, 2008

FrothyChimp said:
Any high enough power of any visible wavelength and near UV as well as near IR will damage your retina the same. All these wavelengths will be focused by the cornea and lens onto the retina. So mW for mW or W for W you do the same damage. There is no preference based on wavelength.

The UV region and mid-IR and far-IR is another story. UV will cataract your lens never making it to the retina. Mid-IR will show signs of retinal damage and corneal/lens damage whereas far-IR will damage the cornea and lens exclusively.

that was what i was trying to say. visible and invisible lasers do different damages. thanks for clearing it up.

suiraM · Dec 25, 2008

lightfoot500 said:
may i suggest the senior members put together a document on proper use of lasers as far as the eyes are concerned. i am a newbie here so i wouldnt be the one to do it.

I'm not a senior member, but I can make such a document. Here it is:

Never expose an eye to direct or reflected laser light. Never expose an eye to diffuse light from a powerful laser. Wear protective goggles for the laser type and power you are using; it's not a question of being able to afford them, as the laser is purchased with the money left over from buying the goggles. No exceptions, excuses, rationalizations or justifications. Make sure you know where windows, mirrors and reflective surfaces are, and be aware of the entire path of the beam until it reaches a matte surface. Don't use a laser around anyone who either disagrees with this policy, or is unfamiliar with it. There is no such thing as a harmless prank when lasers are involved. Let exactly the same people use your laser as you would let screw your girlfriend without a condom. You may not notice laser damage, so leave it to the eye doctor decide if your eyes are okay; seek one out after any accidental exposure.

Pretty simple, huh?

As for the guy who had several accidental exposures, the correct course of action is to go to an eye doctor, explain that accidental exposure to a laser has occured, and then get both a visual field test and a slit lamp examination. Also, pay close attention to your reading speed, both eyes and each eye by itself. Even if you don't notice any damage, that doesn't mean damage hasn't occured. A laser is focused to a tiny spot on the retina, and the brain will try to compensate for it, just like it does with the blind spot in front of the optic nerve. Hence, a dead area in your field of vision may not be obvious. A slit lamp examination will usually reveal any spots that have been damaged. OCT is better, but not readily available.

And I concur with the idea that putting down the laser for good is a good idea. Even a 5mW red is going to look pretty literally like "the light of a thousand suns" when you get it in your eye, at least within its spectral range, so the common sense response would be to avoid repeating that, and the intelligent response would be to get a pair of goggles as well. Since neither has occured, it's safe to say that responsible handling of a green laser or a higher powered red... is probably beyond you.

dvdg101 · Dec 25, 2008

corpse108 said:
Hi. I have a couple of questions.

Where can I find Safety Glasses? I'm having a hard time locating a site that sells them.

I saw the formula to calculate the correct OD but how do I find out the reduction factor of the laser? Does the Class of the laser have anything to do with this?

Thanks,
Josh

http://www.letmegooglethatforyou.com/?q=laser+goggles

Xer0 · Jan 22, 2009

Oh Caligvla... thank god its all alright now, good to hear that your eyes will heal !

This remebers me of the time i was young, my first laser was such a red Souvenir-Shop Keychain thing, i played around at holliday on Mallorca. And so stupid i was about safety, i some times had look into the beam directly. Luckily it not damaged my eyes, at least i think so, i never had any complications after.
had even an eye check last year and remember to been slit-scanned and the doc said everything allright.

Im into Bluray just since Dec 08, my first >10mW Laser. The first time i just played with it and shined around the room, having set the current just-above-threshold. i was curious what it can more, so i turned up the driver for some second and back again, afraid of the radiation. repeated this some times. then the first attemp to burn something, allthough i self said to me when buying, that i dont want to burn things. but i had such a fear of damagin my eyes, so i did it so: 1. reduced the current under threshold 2. focussed the faint dot as small as possible and alignet the "testing object" 3. put the box of my mulitmetre (just griped the nearest rectangular thing laying around) sideways to beam direction to shield me up and only then 4. powered up the driver and enjoyed the smoke rising up ;D i think i had very great luck too because not far away thete was aluminium foil of my chocolate santa so if i would hit it the reflections may have come very very evil.

next day i had fear of having damaged my eyes by looking at the dot on the wall 5ft away
...but it was just my almost daily eye dryness due to my old out-of-focus CRT im using
(yes i know how to fix this, but i not wanna do it myself, there are f*k'n 25kV inside

)

So what i wanted to say... :

I will get Googles at first before building my Scanner this year !!!

And @ Cali: Just the question, you arent using a crt screen, arent you?
Just cuz i feel the same "haze" simptome often after using my PC long...

micallen · Jan 27, 2009

So what would be a safe distance to view the dot on a white wall - good rule of thumb?? Talking specifically about a 50 mw greenie.

Also, I bought it from LED Shoppe. Does anyone know if they have an IR filter?

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