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Thread: Is my math right?

  1. #1
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    Question Back Curve math check

    Hi. I'm working on a project, please check my math.

    What is overall power if the intent were to make a spherical lens with the ideal back curve for equidistance to eye as it moves.

    Back Curve -6 (equidistant for eye as it moves)
    Index 1.74
    Base Curve (Front Curve) .50 (on box)

    Power = (Back Curve + Front Curve) * (.74/.53)
    = (-6+.5) ( .74/.53)
    = 7.68

    {another way to ask my question, when one says the ideal spherical back curve is -6D, is that -6 based on a 1.53 index, and should be adjusted based on the index. If so, I think my math is correct??}
    Last edited by ravenclaw; 03-04-2018 at 12:03 PM. Reason: clearer question

  2. #2
    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by ravenclaw View Post
    Hi. I'm working on a project, please check my math.

    What is overall power if the intent were to make a spherical lens with the ideal back curve for equidistance to eye as it moves.

    Back Curve -6 (equidistant for eye as it moves)
    Index 1.74
    Base Curve (Front Curve) .50 (on box)

    Power = (Back Curve + Front Curve) * (.74/.53)
    = (-6+.5) ( .74/.53)
    = 7.68

    {another way to ask my question, when one says the ideal spherical back curve is -6D, is that -6 based on a 1.53 index, and should be adjusted based on the index. If so, I think my math is correct??}
    Welcome to Optiboard ravenclaw. The math is ok if the thickness is zero. However, the premise that a -6.00D back curve would keep the vertex distance the same as the eye rotates behind the ocular surface is incorrect, with the correct value approximately -16.00D (see Contour Optics/Sola Enigma.

    Hope this helps,

    Robert Martellaro
    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.



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