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Thread: How do you block a Plano D28?

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    How do you block a Plano D28?

    Just as the the title says for edging the lens.

    I spent about 30 minutes moving the lens around the lensometer trying to find OC and could not for the life of me understand why the cross lines didn’t move.

    Durrr.

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    Quote Originally Posted by jakemoore View Post
    Just as the the title says for edging the lens.

    I spent about 30 minutes moving the lens around the lensometer trying to find OC and could not for the life of me understand why the cross lines didn’t move.

    Durrr.
    If you are really a Ophthalmologist I suggest you hire an optician. This is really basic 101

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    Master OptiBoarder optical24/7's Avatar
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    Don, OMD's get zero training in lens fabrication. Plus, Dr. Moore has been here for 10 years...

    Hi Doc. All lined bifocals and trifocals are layed out by the seg using the near PD as reference. The surfacing lab would grind the decentration between near and far. Also, keep in mind a plano power has no prismatic effect unless the lab ground it in on purpose or by accident. With your above lens, just use the NPD as reference and layout the lenses seg accordingly along with whatever drop or raise from datum. Upon verification note that the segs measure to the NPD and that you don't have a prismatic error in the distance area more than 1/3 D.

    I hope this helps.

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    Quote Originally Posted by Don Gilman View Post
    I suggest you hire an optician.
    Somebody keeps getting opticians in my office pregnant so:

    If:
    1) you like hot wind

    2) can write instructions in crayon for your colleagues

    3) don't mind pumping out glasses at medicaid rates

    I will hire you today!
    Last edited by jakemoore; 05-22-2020 at 02:41 PM.

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    Quote Originally Posted by optical24/7 View Post
    Don, OMD's get zero training in lens fabrication...

    ...I hope this helps.
    Thank you for understanding! We are actually trained to avoid any knowledge of lens fabrication. It makes it much easier to avoid embarrassment and deflect blame when a patient gets mad. It's quite hard to shake the old habits.

    Don might be able to hear the gears in my brain grinding all the way up in Cincinnati as I try to parse your instructions. I'm pretty sure when I get a chance to put my hands on it again I will be able to work though it with this advise.

    The ancient texts I have refer to using the distance MRP/OC which I obviously cannot find on this plano lens. Will we get better results if we always do a near reference point?

    Thanks again.

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    Quote Originally Posted by jakemoore View Post
    Somebody keeps getting opticians in my office pregnant so:

    If:
    1) you like hot wind

    2) can write instructions in crayon for your colleagues

    3) don't mind pumping out glasses at medicaid rates

    I will hire you today!
    Would I be able to feed my family, pay a mortgage on a nice home and have money left over for vacation and toys if I let you hire me ?


    If I started selling 2500.00 single pairs of hi tech progressives and combo 4000.00 plus pairs of multi lifestyle/ work style pairs would I get a very respectable bonus ?

    Would you pay my licensing fees if they are needed there ?

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    Master OptiBoarder optical24/7's Avatar
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    Yes Doc, almost always use your near reference point ( the seg) when laying out (blocking) any FT lens. Once again, if your lab surfaced your FT correctly, they put the Distance OC out from the near segs OC 1.5 -2 mm usually to account for convergence at near. Let me give an example;

    Frame PD (A measurement + DBL (distance between lenses) minus near PD/2 = decentration of each SEG.

    Exp;

    frame 52/18 = FPD of 70
    Pt's PD = 63/60
    seg height 15

    Frame B measurement = 34/2 = 17 (datum)

    70 - 60 = 10/2 = 5mm17 - 15 = 2mm

    So you'd layout the seg 5 in and 2 down. If your lab ground the right amount of decentration (1.5 in ou) your distance PD will be correct also.

    Once again, on your plano lens, There is no power so there is no prismatic effect . You can move the lens all around in the lensometer, but the "OC" is not gonna move. With your plano in dist. all you need to worry about is unwanted ground in prism. But the seg does have power, therefore, you need to get your NPD correct.

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    Quote Originally Posted by jakemoore View Post
    Somebody keeps getting opticians in my office pregnant so:

    If:
    1) you like hot wind



    3) don't mind pumping out glasses at medicaid rates

    I will hire you today!
    If I wasn't a geezer I would take you up on it and you'd have no fear of me getting pregnant or visa versa and if I had a half day to hunt and peck with one finger I would have give you the same answer as Optical 24/7

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    Quote Originally Posted by Don Gilman View Post
    If I wasn't a geezer I would take you up on it and you'd have no fear of me getting pregnant or visa versa and if I had a half day to hunt and peck with one finger I would have give you the same answer as Optical 24/7
    but if he hired me, he wouldn’t need an answer because I would have already edged and mounted the lenses, maintained the edger, trained the staff ....

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    Quote Originally Posted by jakemoore View Post
    Just as the the title says for edging the lens.

    I spent about 30 minutes moving the lens around the lensometer trying to find OC and could not for the life of me understand why the cross lines didn’t move.

    Durrr.
    You did find the OC. It's sometimes said that a plano lens has no OC, but really a plano lens has an infinite number of OC's.

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    Master OptiBoarder AngeHamm's Avatar
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    Check your edger manual. Lined multifocals are nearly always edged using the near PD and seg height, and your edger probably has a setting for exactly this. Our Santinelli, for example, simply has us choose the "BF" setting and bblock the lens up with the seg 5 in and 5 down.
    I'm Andrew Hamm and I approve this message.

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