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Thread: aspheric lenses

  1. #1
    Rising Star
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    Question aspheric lenses

    :hammer:

    I checked a lens today to see if it had an aspheric front surface
    the lens measure moved about 2 dioptres!
    It was a - 5.00ds
    The lens size was about 47
    Im sure normally it moves less than 1 dioptre
    I hope one of you guys can explain this

    Thanks

    Alan



    :cheers:

  2. #2
    Bad address email on file Susan Henault's Avatar
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    PLEASE don't be offended by my asking -- I just thought I would inquire and eliminate any obvious possibilities:

    Was this a progressive lens?

    If not, what is the lens manufacturer, brand name, material etc?

  3. #3
    Rising Star
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    Dear Susan

    Thanks for replying

    Lenses are plastic single vision
    centre subs 1 mm
    some sort of high index
    dont know who they are made by

    thanks

    Alan

  4. #4
    Rising Star
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    Hi patient came in again so I had another look

    I moved the lens measure over the front curve of the lens and got readings +2.00 to +5.50 approx
    back curve I got -6.00 to -10.00
    lens measure calibrated for 1.523
    some sort of bi aspheric?

    Reading in the focimeter is a straight forward -5.00

    Help

    Alan :hammer:

  5. #5
    Bad address email on file Rich R's Avatar
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    The lenses could be warped, especially if they are thin center.
    I don't think I've ever seen that much, may also be compounded by stress on the lens from being in the frame tight.
    Rich R.

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