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Thread: changeover

  1. #1
    Bad address email on file
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    Idea changeover

    can someone help me with the following please:

    would this changeover be acceptable:
    R: -4.00/-1.00x90
    L: -4.00/-1.00x90

    change over to replace a clients broken frame is 56-14
    new frame is 56-12.
    the shape of the new frame does not allow for any alteration of the decentration of the OCs. that is, they must be fitted on the new frame's GCD.

    Thanks.

  2. #2
    Underemployed Genius Jacqui's Avatar
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    You're createing a diopter of horizontal prism. I don't know about the patient, but my eyes wouldn't like it at all. Personally, I would try to convince the patient to buy new lenses.

  3. #3
    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by benice View Post
    can someone help me with the following please:

    would this changeover be acceptable:
    R: -4.00/-1.00x90
    L: -4.00/-1.00x90

    change over to replace a clients broken frame is 56-14
    new frame is 56-12.
    the shape of the new frame does not allow for any alteration of the decentration of the OCs. that is, they must be fitted on the new frame's GCD.

    Thanks.
    It might depend on the accepted tolerances for horizontal prism in your area. In the United States, ANSI Z80.1-2005 specifies...

    ......Power.........................Tolerance

    ≥ 0.00 D, ≤ ±2.75 D.......... ±0.67 Δ Total

    > ±2.75 D.......................±2.5 mm Total

    Each eye would have .5^ of base out prism induced, for a total of one prism diopter, with a positional error of 1mm per eye, for a total of 2mm. That's within tolerance for the power given in your example on the 180 merdian, so yes, it would be acceptable.
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



  4. #4
    Cape Codger OptiBoard Gold Supporter hcjilson's Avatar
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    But then again, there's always the "bridge stretcher".....doesn't work too well with metal, but plastic is a breeze! :)
    "Always laugh when you can. It is a cheap medicine"
    Lord Byron

    Take a photo tour of Cape Cod and the Islands!
    www.capecodphotoalbum.com

  5. #5
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    Actually most metals will increase a little if you flatten out the curves usually found in the bridge.
    Course it helps, if you do it neatly and uniformly.
    Chip

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