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Thread: EXACT Rx NVF

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    Master OptiBoarder tx11's Avatar
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    EXACT Rx NVF

    Which Near Variable Focus lens do YOU use when you want to dictate the EXACT Rx that will be in the lenses without some formula changing it?
    Last edited by tx11; 01-16-2018 at 12:26 PM.

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    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    I don't think you can.

    They're not designed to specify rx's that way.


    You can specify the upper portion of the lens but you still need to choose a fixed digression power between -.75 and -2.00.

    I've tried it a couple of times but it opened up the proverbial can-o-worms so I don't go there anymore. My go to fwiw is Shamir Computer and Workspace.

    I believe you can do that with something like the old standard computer progressives but that's not the same as a NVF.

    Someone can feel free to correct me if I'm wrong.

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    My Brain Hurts jpways's Avatar
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    I actually called Shamir Technical support last week asking if this was possible and the answer they gave me was that I would "always be chasing the add" in order to get the prescription I wanted.

    So (assuming the patient goes through with it) what I am going to do is use a Shamir Duo where I'm raising the seg height to raise the add up to the where intermediate would be on a progressive to counteract the 13mm drop between the MRP and the top of the 1-2mm transition zone (according to Shamir). I'm going to guess 7 mm to start but I won't be surprised if I have to raise it another 2-4mm. This patient is dead set against having a line.
    Last edited by jpways; 01-16-2018 at 01:33 PM.

  4. #4
    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by tx11 View Post
    Which Near Variable Focus lens do YOU use when you want to dictate the EXACT Rx that will be in the lenses without some formula changing it?
    I use standard multifocals and partition the add power as needed. For example, the Rx is Plano Sphere add +2.50 OU, with work distances that are 24" and 16" to the monitor and desktop respectively. Refract those distances, typically +1.50 and +2.50, ordering +1.50 Sphere add +1.00 OU. For PALs, choose choose a design that has a generous distance zone, especially when using 45" screens or dual/triple monitors.

    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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    Quote Originally Posted by Robert Martellaro View Post
    I use standard multifocals and partition the add power as needed. For example, the Rx is Plano Sphere add +2.50 OU, with work distances that are 24" and 16" to the monitor and desktop respectively. Refract those distances, typically +1.50 and +2.50, ordering +1.50 Sphere add +1.00 OU. For PALs, choose choose a design that has a generous distance zone, especially when using 45" screens or dual/triple monitors.

    Hope this helps,

    Robert Martellaro
    We do pretty much the same thing with our FastGrind software when calculating for Computer glasses. Our software asked for a screen distance that the patient would be comfortable sitting, NOT where they have to sit now, and then calculates the distance and add power from the original Rx entered, and our Addvantage plus PALs have 100% clear vision side to side. I usually recommend a short corridor. So far, so good for the past 5 years. easy peazy.

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