Eyeglasses and prescription question

Discussion in 'Glasses' started by lasik advocate with flap melt, Sep 12, 2003.

  1. My son's prescription is plano, +2.25 x90
    His eyeglasses instructions say +2.25, -2.25 axis 180.

    I thought when they rotate the prescription to make eyeglasses that
    it's a 180 degree rotation, not a 90 degree rotation. Wouldn't the
    axis still be at 90 instead of 180? Did they make a mistake or am I
    missing something?

    My son's only 5 so it's hard to tell if his vision is better or worse.
    He says the glasses make his vision better, but I want to be sure. .
    ..
     
    lasik advocate with flap melt, Sep 12, 2003
    #1
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  2. lasik advocate with flap melt

    Dr. Leukoma Guest

    (lasik advocate with flap melt) wrote in
    No. The axis is rotated 90 degrees. 180 makes no sense, since it winds up
    being the same. The notation is based on a 180 degree convention, not 360
    degrees.

    DrG
     
    Dr. Leukoma, Sep 13, 2003
    #2
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  3. So 90 degrees one way and 180 degrees the other way are the same
    location? I thought it would be 180 degrees different, not 90
    degrees? Would you mind explaining?
     
    lasik advocate with flap melt, Sep 13, 2003
    #3
  4. lasik advocate with flap melt

    drfrank21 Guest

    If you rotated 180 deg you'd be back to the original rx! The transposition
    of the rx'es you stated are correct- just in different forms (plus cylinder
    converted to minus cylinder).

    frank
     
    drfrank21, Sep 13, 2003
    #4
  5. Thank you all for the explanation.

    I don't want to take any chances knowing what I know now. I Appreciate it.
     
    lasik advocate with flap melt, Sep 13, 2003
    #5
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