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How Does the Retina Work?

  1. Aug 31, 2011 #1
    I'm wondering how it's possible for vertebrates like us to see so well, or at all, if our photoreceptors are actually pointed away from the light focused on the retina. I would assume that the light would just pass right by the photoreceptors and we wouldn't be able to see much except for the presence or absence of light.

    The fact that photoreceptors are pointed away from the light seems like it wouldn't allow for good vision similar to how you can't see the sun if your head is turned away from it. Yet it works for us and many other vertebrates with even better vision but the same design. How?
  2. jcsd
  3. Aug 31, 2011 #2


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    Part of the answer seems to be that some of the glial cells in front of the retina act like fiber optic cables to channel the light from the retina to the photoreceptor cells. See the following paper:

    Franze et al. (2007) Müller cells are living optical fibers in the vertebrate retina. Proc Natl Acad Sci USA 104(20): 8287. doi:10.1073/pnas.0611180104, PMC:1895942

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