Table of Dk values for Silicon Hydrogels

Discussion in 'Optometry Archives' started by MS, Nov 10, 2007.

  1. MS

    MS Guest

    Recently, in another thread, I asked about such a table.

    I just found one, so I'll post the link here, in case anyone else is looking
    for such a table:

    If the figures on the chart are correct, I find one thing I find a little

    The chart shows both Acuvue Oasys and O2 Optix as having higher Dk values
    than Purevision. Yet neither are approved for 30 days wear, as is

    Biofinity has the second highest dK, second only to Night&Day. Yet they are
    currently approved in the US only for daily wear. (I believe they have been
    approved for 30 days wear in other countries, however, and will probably
    eventually have that approval in the US.) (Why does such approval always
    take longer in the US?)

    I wonder though, why Oasys and O2 were not submitted for 30 day approval?
    (Or, if they were submitted, why not approved?)

    According to the chart, Advance only has a dK of 60, much lower than the
    others. I'm surprised that a si-hy lens would have such a low dK. (And
    surprised that my eye doc would tell me (see thread about toric si-hys) that
    the Advance has a higher dK than Purevision, and is approved for 30 day
    MS, Nov 10, 2007
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  2. MS

    Mike Ruskai Guest

    There's more to extended wear than oxygen permeability. The Acuvue
    lenses both tend to collect deposits more than the PureVision and N&D

    Your OD's confusion about Acuvue Advance is just an excellent example
    of why you shouldn't assume a professional knows everything about his
    or her profession. Informing yourself is always a good idea.
    Mike Ruskai, Nov 10, 2007
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