Where do they put the cylinder correction?

Discussion in 'Optometry Archives' started by Guest, Mar 18, 2006.

  1. Guest

    Guest Guest

    In this prescription for farsightedness:

    Sph = +1.75, Cyl = +1.25, Axis = 174

    How is the cylinder correction ground into the lens?
    I.e., is it in the shape of an X at the proper axis?
    Or is it ground all over the lens at the proper axis?

    And which way is that correction ground as viewed from the *front* of
    the lens rather than from the side the eye is on?

    I.e., does it slant uphill from lower left to upper right, or does is
    slant uphill from lower right to upper left?
    Guest, Mar 18, 2006
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  2. Guest

    Guest Guest

    Now I'm all mixed up :) I thought 174 degrees was almost horizontal,
    but you're saying it's almost vertical?

    Which way is straight up and down? I thought that was 90 degrees, and
    that horizontal was 180 degrees.

    Are you saying that the pointy ends of the football shaped part ground
    into it are near the top and bottom of the lens?
    Guest, Mar 18, 2006
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