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Thread: This is amazing

  1. #11
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    I've never experienced flash burns from a welding arc, but I've met several people that have. (Back in my Navy days, especially when we were in the shipyard...) They explained it as akin to having hot sand in your eyes and not being able to flush it out. (Burning, plus a scratch-like pain that won't go away.)

    Doesn't sound like fun. (I understand it's basically a sunburn for your eye, caused by the UV of the arc... Right?) And they all said that the pain lasted for several days, though it didn't really hurt when they were being exposed to the arc in the first place.

    Either way, I've always shielded my eyes around welders after talking with those folks.

    Adam

  2. #12
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    I have seen this page before and wondered about how much bs it was spouting. He does make the point that he is stupid, which we all know is true - why would anyone look deliberately into a laser just to prove the point?
    I myself had a burst of 80-100mW of 532 at a range of about 6 inches. My reflexes shut my eye and turned my head away pretty sharpish but I did recieve eye damage. As it happens his image marked 'Destructive (permanent) injury' very closely resembles what I saw. It wasn't painful as such and I could see a shadow there for about 48 hours but my eye recovered to a degree so I no longer see a shadow. What I do see when I am looking at a straight line is a distortion of the line - so if i look at ruled lines on a page for example I see one line above and to the left of my centre of vision which will have a sort of dip in it - like its not straight. I take this as being mybrain compensating for the missing "pixels". The damage is to my left eye and does not bother me or inhibit me in any way - most of the time I forget its even there. The aftereffects I suffer/suffered do not resemble what he dipicts at all. For me it wasn't colours being changed and fuzzed but just the shadow like his 'destructive injury' fading gradually over a couple of days.
    I guess the effects will be different for different people and it will depend on where it hits - I guess if it hits where the optic nerve exits then it will be goodnight vienna for that eye.

    But then I remembered that the experiment above was repeated a few years laser with *green* DPSS pointers
    My understanding of this is that the eye is more likely to be damaged by green light than red, as green is readily absorbed by the red blood cells we have and I'm sure there are plenty knocking around in the vessels at the back of the eye. If you shine a red pointer at your hand it will make your hand glow red but a much more powerful green won't be seen - or hardly seen - that is until it burns right through and exits the other side

    An interesting point I read once - possibly on Sams FAQ was that many permanently laser damaged eyes have a spiral burnt onto the retina when examined, which is caused by the eye searching trying to work out what the light is and where the source is & Im guessing that this is with reference to ir. Dunno if thats true. Also People who are blinded by high power YAG lasers apparently report seeing a bright flash of green light before it all goes dark as the Vitreous humor of your eye acts as a non linear element and frequency doubles the 1064 into 532.

    Rob

  3. #13
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    I have 15+ years of laser exp ranging from .5mw to 40+ watts of yag and still see fine, been hit more times than i can remember.
    The only thing i can think of is maybe his cheap laser pointer didn't have a ir filter and some of the damage was caused by ir.

    I do have a friend that just glanced out of the corner of his eye at the reflection from a ultra fast femtosecond pulse laser and it took him years to get his vision back to normal. Poor guy was in japan at the time on a service call, he said it was scary being away from the firmilar, at japanese opthamologists trying to figure out haw bad the damage was.

    I guess the moral of this story is do not stare in to ANY power of laser on purpose!!! DUH !1!!

    Chad

  4. #14
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    Yes, I agree. 15mW really should not be sufficient to cause this kind of damage so quickly. But in the UK, they have seen a lot of cheap Chinese laser pointers with no IR filter. Also, although the pointer was rated (supposedly) at 15mW, it may have been putting out dramatically more. I have seen cheap DPSS lasers go down, AND UP in laser power...

    Best regards,

    William Benner

  5. #15
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    Quote Originally Posted by Pangolin
    ...in the UK, they have seen a lot of cheap Chinese laser pointers with no IR filter.
    It gets worse. People are taking 100 mW greens of dubious heritage, removing the IR filter, selling them as multi-hundred milliwatt lasers, in some cases labelling them with vague 'safety' stickers blurring the distinction between class 3 and 4 deliberately to make people think they're getting 2000 mW or more!

    I don't know who exactly is doing what, there are now a few people at it on eBay. One sold for 500, cost me a wasted listing or two because I won't sell a laser dishonestly, so the mug punters are flocking to where they think they'll get more power. I protested openly on my listings to draw attention to this, and one seller says he wants to meet me to 'discuss why I'm not happy with what he is doing'. I won't name him, unless he makes good by force on what appears to be a direct threat to me. There are dangerous lunatics out there! These people would sell the dumb joyboys several hundred milliwatts of IR and suggest that they use these things to scan audiences in small clubs, just to get a bit of loot.

    To me it's the same as selling replica firearms on eBay, then telling (and advising) buyers how to ream them out to take real bullets. It's the single most dangerous threat our interest in lasers has faced so far. eBay come down like a ton of bricks on a laser pointer of over 5 mW. Can you imagine what they will do to restrict our trading opportunities if this gets out of hand? It would go beyond eBay, governments would legislate ruthlessly to stamp it out, at our great expense. We have to stop it ourselves, if we can.

  6. #16
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    What a frickin' idiot.

    If we go by the last post date, at least he hasn't done anything with lasers in the last year and a half.

    OMG! I was reading the account again (had to blog about this moron) and he actually hit himself in the eye with the laser THREE times! What a maroon. (you gotta be old to get that reference)

  7. #17
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    "What a maroon. (you gotta be old to get that reference)"[/quote]

    The Three Stooges, right?

  8. #18
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    This is pretty sad if its true... I have a "hole" in my vision though, in fact we all do. There are a couple of ways to find it and with a laser it is very easy. And for most people it is in exactly the same spot. Most of you folks may already know about this, but if not, try this:
    -Place a sheet of paper on the wall with a large black dot.
    -Stand about 3 feet away from the wall.
    -Stare directly at the black dot with your left eye closed
    -Use a laser pointer and point it at the black dot, slowly move the pointer to the right while continuing to stare at the black dot
    -When the laser pointer is roughly a foot to the right of the black dot, it will appear to go away.

    While continuing to stare at the black dot, you can move the pointer around the "hole" and see that it is fairly large! I learned this quite a few years ago when I worked at a museum, if I remember correctly, it is where the optic nerve comes together and carries its signal to the brain, with the right eye, it is to the right of your center of vision and with the left eye it is to the left of the center of vision.

    David

  9. #19
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    I dont belive 15mW can do so much damage...
    I got my 400mW red into the eye ops:
    And I still notice a white spot on my eye..
    I never notice it on a regular day, but if I look at a white computer screen and flash my eyes.
    Then I can se the spot....


    I have another question, can the "doctor" scan the eyes to find out if it`s burned ???
    (like the dentist scan the tooth)

    :P

  10. #20
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    I think a lot of us have had an "incident" or two. I just have a lot of "floaters" in my vision. I dont know if its laser related or not. I bet a good opthomologist could look with that thingy that they use at the retina and be able to tell if there is damage or not.

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