effect of unwanted prism in glasses?

Discussion in 'Glasses' started by Yorkie Bar, May 31, 2006.

  1. Yorkie Bar

    Yorkie Bar Guest

    Hi,

    I recently got new glasses. Only trouble was, when I put them on, I saw
    double. Two people, two of everything etc. After investigation by the
    optician, she said it was because there was 'prism' in my old glasses and
    none in my new ones.



    The only trouble was, nobody in the past had told me I needed prism and it
    wasn't picked up in the examination I had for this current pair. The
    optician said it was possible that the people who made my glasses five years
    ago put prism in 'accidentally' and that my eyes are now 'used to prism',
    meaning I now need it regardless of whether I originally did or not.



    Does anyone know (or could hazard a guess) as to what would happen to
    'normal' eyes after looking through prism glasses for five years?



    I have read that needing prism means you have a condition like 'lazy eye' -
    but I certainly don't have any obvious signs of my eyes going in different
    directions, so I'm a bit confused.



    Thank you in advance for any ideas!

    cheers,
    yorkie bar
     
    Yorkie Bar, May 31, 2006
    #1
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  2. Yorkie Bar

    CatmanX Guest

    it depends on the prism induced. If it were vertical prosm, I would
    expect you would have noticed it immediately you got the original
    glasses, so I will assume it is horizontal prism. This is often induced
    when the lens fitter is lazy and doesn't decentre the lenses (common in
    Asia). Myopes cope very happily with the base in prosm induced, so they
    don't have to converge as much, but they hate it when they get their
    next pair and they are made correctly and have to converge again.

    You will adapt to it over time, but it can be an issue for a while.
     
    CatmanX, May 31, 2006
    #2
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  3. Yorkie Bar

    acemanvx Guest

    do you see double without glasses? If nothing is wrong with your eyes,
    give it time, youll soon get used to your new glasses and wont see
    double anymore
     
    acemanvx, May 31, 2006
    #3
  4. Yorkie Bar

    Neil Brooks Guest

    Thank God for your follow up, Ace.

    Without it, the original poster would have had to take the word of an
    actual eye doctor.
     
    Neil Brooks, May 31, 2006
    #4
  5. Did you wear the new ones for a while? If the doubleness went away
    after a few minutes/hours, you may not have needed it. If it didn't,
    you do need it. If you didn't try them more than 10 seconds, all bets
    are off.
    No guess at all. Normal binocularity adapts readily to prism in most
    cases, both horizontal and vertical, and in surprising amounts. Takes a
    while, but does happen for normals. People who need prism don't adapt
    as well to erroneous prisms. A normal who so adapts to an inadvertent
    prism will take about as long to "unadapt" as the initial adaptation took.
    Most binocular imbalances are not so great as to cause an obvious eye turns.

    w.stacy, o.d.
     
    William Stacy, Jun 1, 2006
    #5
  6. Yorkie Bar

    acemanvx Guest


    except for the fact im not a doctor. The doctors know what to do, one
    of them mentioned trying to unadapt to the prisms you dont need.
     
    acemanvx, Jun 1, 2006
    #6
  7. Yorkie Bar

    LarryDoc Guest

    And you felt compelled to write what was already written
    because..................

    Find the off switch already. You have no value, no purpose here. The
    fact that you don't get that is proof enough that you don't.
     
    LarryDoc, Jun 1, 2006
    #7
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