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Why is the human retina so large?

  1. Apr 2, 2015 #1

    fluidistic

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    Apparently the retina of humans covers about 65% of the surface of the interior of our eyes.
    But most light is focused around the fovea centralis and if it isn't focused around there, we lose resolution. I understand that at night it's better not to focus too close to the fovea centralis but still, I see no way that light somehow ever reaches maybe 40% or 50% of cone and rod cells.
    Am I missing something? Why do we have a so large retina?
     
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  3. Apr 2, 2015 #2

    mfb

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    Is it? The light from the center of our field of view, sure. The light from other directions is not.
    We lose resolution, but it is still sufficient to see moving things - and in general, something that moves is very interesting and you don't want to miss it.
     
  4. Apr 2, 2015 #3

    fluidistic

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    That explains everything, thanks. I just tested with my finger and I all makes sense now, I guess almost all or all cones indeed get light.
     
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