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Hypermetropian eye question

  1. Apr 17, 2008 #1

    fluidistic

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    My question is : Why do hypermetropian people not see reversed?
    According to wikipedia and many other sources, the light from a non reversed object arrives at the retina in the same sens, that is, non reversed. As we know, when interpreting images, the brain reverse the sens of the image on the retina. Therefore the brain "see" reversed.
    So I am asking to people that knows, or hypermetropian people : If you put a correcting glass in front of an hypermetropian eye and take the glass off, the brain should see in the right side and then reversed? Another example can be on a hypermetropian person. Put a correcting glass on only one eye : the person should see reversed from this eye and not reversed on the other eye.
    But as far as I know, there is nobody that see reversed... So it must be an explication that I don't know. Does someone know more about the subject?
    Thanks in advance.
     
  2. jcsd
  3. Apr 9, 2009 #2

    fluidistic

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    Sorry to bump this old thread but I would really like to know the answer to this question.
    I reformulate it since I didn't know English as I do today even if it's still poor.
    Here I go : According to what I've been taught in High School and according to wikipedia :http://en.wikipedia.org/wiki/File:Hypermetropia.svg, the light coming from an object and passing through the eyes of hyperopian people don't have time to get inversed (by the lens) so that it hit the retina in the same orientation as the object is.
    But when the brain convert the electric signal (or whatever it is) given by the retina through the optic nerve, it inverse the orientation of the one the object hit the retina.
    For example in people that don't suffer any eye anomaly or people that suffer from myopia, the light of any object that pass through their eyes ends in a reversed orientation on the retina. So that the brain inverse it once again and this makes a "right" image.
    Hence people suffering from hyperopia should see reversed.
    But as far as I know, they don't. So what's going on? Are all the informations of wikipedia and all that I learned about hyperopia wrong? Or is there another explanation?
    If my question is not well explained, please let me know and I'll try to correct it.
     
  4. Apr 9, 2009 #3
    Hyper[metr]opia (long sightedness) merely blurs the light reaching the retina, it does not change the fact that the image there is inverted.

    Nonetheless, the brain would simply adjust automatically within a few days, as proven by an experiment that gave people special mirror-glasses to flip everything they see. (Google for it.)
     
    Last edited: Apr 9, 2009
  5. Apr 9, 2009 #4

    fluidistic

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    Thank you very much cesiumfrog. I'll google the information you gave me.
    I've been rude to wikipedia by saying that all the information they provide on hyperopia is wrong, but at least their picture about how the light behave in a hyperopian eye is erroneous since it should show the light focusing before hitting the retina so that the image on the retina is reverted.
    Quoting wikipedia :
    Thus according to them the image on the retina is not reverted as you said, so they're also wrong on that.
    EDIT: I just googled hyperopia and all I read was in wikipedia's favor. So in fact the light doesn't focus in the eye but would focus behind the retina if it could and it reach the retina in a non-reversed orientation. The conclusion is that they see reversed.
    The problem I have with this is that when they use correcting glasses, they should notice that their vision get inverted instantly.
    By the way I didn't find the mirror-glasses experiment in google. (it redirect me on this page and the other pages don't seem to talk about it).
    EDIT 2 : I just found this site : http://www.stlukes-eye.com/Conditions/Hyperopia.asp, which shows that the image is reversed on the retina, explaining everything. (Hyperopic eyes don't see reversed!).
    I just don't understand why the image is not reversed when on the retina.
     
    Last edited: Apr 9, 2009
  6. Apr 9, 2009 #5
    You're misunderstanding ray-diagrams. This is very common. Unfortunately, many of the ray-diagrams that you see seem to be drawn by artists who don't really understand ray-optics themselves.
     
    Last edited: Apr 9, 2009
  7. Apr 9, 2009 #6

    fluidistic

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    In a year I should be studying optics in Physics, so I'm sure I'll understand really what's going on.
    But for now I can say I'm very happy to know that the image of an object is reversed on the retina even for a hyperopic eye. It solves a question I had for 7 years.
    Thank you so much.
     
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