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Thread: My eyes got the thumbs up today:)

  1. #1
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    Default My eyes got the thumbs up today:)

    As the title says, I was a bit concerned after getting a scan in the eye from a cheap Chinese laser at a club - believe me it hurt! Problem was the beam was only split 2 ways at 1 point in sound to light mode whilst it scanned and was a pencil beam not a fan, so I copped exactly 50% power! Believe the laser was somewhere between 30-100mw so I probably had between a 15-50mw exposure.

    Anyway, I had to go for an eyesight check today so I told the optician and got them to check the retina and back of the affected eye - no signs of any damage and no signs of any burns.

    Best thing was, after correction I had better than 6:6 vision! I could read the line below no problem.

    Result.

  2. #2
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    I had similar tests done last month. I saw an optometrist and then two ophthalmic surgeons just to be sure. They found a little spec of debris in my left eye, but that's it. (I had previously thought this was, perhaps, related to laser exposure)

    I'm still not 100% convinced I'm in the clear, but then again, the senior surgeon I spoke with seamed really confident and he *does* work with lasers himself.

    -Jonathan

  3. #3
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    That's great news from both of you! I've seen platinum's laser. It's really scary! Stay safe!

    James.

  4. #4
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    Quote Originally Posted by RGBLaserFan View Post
    Problem was the beam was only split 2 ways at 1 point in sound to light mode whilst it scanned and was a pencil beam not a fan, so I copped exactly 50% power! Believe the laser was somewhere between 30-100mw so I probably had between a 15-50mw exposure.
    O.K., so, you say the beam was split two ways... "so I copped exactly 50% power!"

    Think about this statement carefully, let's assume the laser is giving out a stable 100mW as it hits the scanners. There were two beams being emitted from the aperture, Beam A and beam B. This translates to the scanners being in Position 1 for beam A and position 2 for beam B (you don't see light between the two beams because of the laser being blanked). Your laser is giving out 100mW, so when the beam hits the scanner at position 1 it is giving out 100mW and when the scanner moves to position 2 it's also giving out 100mW. Therefore Beam A must be 100mW and beam B must be 100mW.

    What you see are two beams because of the speed of the scanners and the blanking, but the reality is there is 100mW in each of those beams.

    I have to confess to being the worlds worst teacher, so that's probably as clear as mud

    Cheers

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  5. #5
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    it made perfect sense jem

    and good point just cause there were a 2 lines does not mean the power was cut in hald but its true that with the more lines you do or bigger graphics not all the dots will have the same amount of power on them but with something as small as 2 dots they will most likely be full power
    -Josh

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    Well could be Jem, I'm no expert on laser technicalities. All I do know is that it was a single aperture laser with a blue case, I'm pretty sure it was a SHINP unit. It looked to me like a split beam but given the speed at which light travels its equally possible that each beam was being drawn alternately but so fast that the eye couldn't discern the difference.

    As it caught me only in the corner of the eye it could have even been the heat hitting the white of the eyeball that I felt as the retina has no pain receptors and this did hurt for almost 1/2 hour afterwards. I definately got some light in the eye though as I was temporarily dazzled and definately had an aversion response! That said, no one complained ut then again this effect only seemed to happen once. Most of the scans were fans or multi wider nbeams which seemed to cause no problems.

  7. #7
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    Cool

    Quote Originally Posted by Jem View Post
    O.K., so, you say the beam was split two ways... "so I copped exactly 50% power!" <snip>
    What you see are two beams because of the speed of the scanners and the blanking, but the reality is there is 100mW in each of those beams.
    Or, to explain it another way, there is a difference between *average* intensity and instantaneous (or per-exposure) intensity.

    *Both* need to be taken into account when calculating the MPE, and the per-exposure intensity is usually the limiting factor.

    Adam

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    Very eloquently put Adam. I understand the principles but have difficulty expressing them. As I said, i'm the world's worst teacher

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  9. #9
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    Though usually with cheap chinese lasers, when they are blanked too fast they dont come up to full intensity. Also you have to consider the fog or haze it was going through, that takes ALOT of power from the total output. If you have a fog machine, when you shoot out some smoke, try shining your laser right where it comes out, the dot on the other side will be quite dim, if visible at all!

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