Locating New Lenses In The Frame Question ?

Discussion in 'Optometry Archives' started by Bob, Sep 2, 2010.

  1. Bob

    Bob Guest


    Was wondering about this a bit.
    Had a "discussion" with my Optician re.

    When new lenses are put into the frame, is the center of curvature of
    the lens supposed to be directly in line with the eyeball's center (I
    guess thru the middle of the Iris ?) ?

    Or, as he said, the geometric center of the lens, in the vertical
    dimension, is just put 1/2 way vertically in the frame ?
    The horix. apparently he felt should be in line with the eye's center;
    only the vertical that
    we disagreed about.

    I might not be all that clear in phrasing this.
    So, if not, could someone please explain how the lens' optic center is
    determined, and how it should be
    located and placed in the frame ?

    Much thanks,
    Bob, Sep 2, 2010
    1. Advertisements

  2. Bob

    Mark A Guest

    If the optical center of the lens is 1/2 vertically in the frame, then it
    will usually be near the center of the pupil. However, for most frames the
    fitting height (where the optical center of the lens is placed in the frame)
    is a little above the center of the frame.

    A lens is never put 1/2 way the distance in either direction without first
    measuring. It depends on the frame and how it sits on your face. This is
    measured by first fitting the frame on your face and adjusting the nose pads
    and temples, etc (with the temporary plastic lens in the frame). Then with
    you looking straight ahead, the optician observes where your pupil is on the
    temporary lens and they mark it with a pen and then measure the fitting
    height. Pupil distance is measured without wearing the frame and is the
    distance from the center of your nose to the pupil..
    Mark A, Sep 2, 2010
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.