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A fun trick to see the vasculature of your eye!

  1. Dec 23, 2011 #1
    In this video, the narrator explains why you aren't normally able to see the network of blood vessels in front of your eye, and a neat trick to actually see it. I thought it was really cool.

    http://www.youtube.com/watch?v=L_W-IXqoxHA&t=3m8s
     
  2. jcsd
  3. Dec 23, 2011 #2

    Ivan Seeking

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    Haha, very cool. Ever since college I've been using the finger pinhole technique as a lens when I can't quite see something, but didn't know about this one.
     
  4. Dec 23, 2011 #3
    Isaac Newton experimented with his own eyes to the point where he could have been blinded.

    He would take a narrow dowel and probe near the back of his eye to produce black spots (seemingly opposite to where he was prodding). Part of his "Opticks" research?

    I believe all of us have done this to some degree.
     
  5. Dec 23, 2011 #4
    Wowzer! Very neat! Very easy to do!
     
  6. Dec 23, 2011 #5

    Ivan Seeking

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    Snorting high voltage, yes, but never a poke in the eye. That's nuts!
     
  7. Dec 23, 2011 #6

    Borek

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    Whoa, it works!
     
  8. Dec 23, 2011 #7

    fluidistic

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    Trying for 5 minutes on different surfaces (white paper, white wall, white board) under a lightbulb, I see nothing special. :/
     
  9. Dec 23, 2011 #8
    I think it works best if you have all the other light blocked out so you're only seeing through a tiny hole. I made the hole in an old hockey ticket, about 1mm in diameter. Try the white background on a computer screen.
     
  10. Dec 23, 2011 #9

    Q_Goest

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    Not working for me either... guess I'm not normal. <sigh>
     
  11. Dec 23, 2011 #10

    fluidistic

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    How is it supposed to look like? Like eye floaters? If so, since I suffer from myodesopsia this might explain why I don't notice anything.
     
  12. Dec 23, 2011 #11

    Ivan Seeking

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    I see a faint pattern of squiggly lines around the center of my field of vision. It is subtle but clearly there.
     
  13. Dec 23, 2011 #12

    DaveC426913

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    The trick is to
    1] aim at a bright source. I'm using a fluorescent ceiling panel.
    2] make your movements smaller than the size of the pinhole. So, my pinhole is 1mm, I'm making my movements <1mm.

    What isn't clarified is how far from your eye you hold the card, but I'm doing about 3".
     
  14. Dec 23, 2011 #13

    DaveC426913

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    Kinda like eye floaters but squiggly lines.
     
  15. Dec 23, 2011 #14
    I would call the image I see a "diffraction pattern."
     
  16. Dec 23, 2011 #15

    fluidistic

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    I'm seeing something, I guess it must be it. I use my hands and 1x0.3 cm wide opening approximately. I move the aperture probably a bit more than its size. When I use smaller apertures I see the same thing but light has less intensity due to diffraction I think so a huge aperture works fine. Even a 1x1 cm aperture work although better around the edges.
    I wish the brain would stop to "see" eye floaters too.
     
  17. Dec 23, 2011 #16
    Wow that's awesome. I did it and I could see a textured relief-like image very clearly - you can even kind of follow the pattern by turning your head a little so the light is coming in at slightly different angles.
     
  18. Dec 23, 2011 #17

    wukunlin

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    doesn't work for me, I think to too severely astigmatic and myopic
     
  19. Dec 23, 2011 #18

    Evo

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    This explains what I've been seeing. It looks like a rosette where only the wavy tips of the open rose are traced in a light gray. I see that every day.
     
  20. Dec 24, 2011 #19

    Borek

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    I think it shouldn't matter, it is not about where the light is getting focused.
     
  21. Dec 24, 2011 #20

    Chi Meson

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    Oh wow, that is awesome. I don't know if it is because I am very farsighted, or if that doesn't matter, but I immediately see the entire network of vessels. ; I could draw a complete map if I needed to.
     
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