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  1. Darryl's ashtray analogy is a very user friendly...

    Darryl's ashtray analogy is a very user friendly visualization of how and why unwanted cylinder is distributed in different ways with PALs.
    ...
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    They stood half a million people on their heads,...

    They stood half a million people on their heads, shifting the earth's axis ever so slightly.

    Here's the full drum solo and outro (audio only).

    https://www.youtube.com/watch?v=7dTH32ClRwI
    ...
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    The mires should be clear and sharp, making sure...

    The mires should be clear and sharp, making sure that the lens is clean and that the instrument is calibrated and focused (I usually didn't have access to a radiuscope, instead using a keratometer)....
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    1) Lowest density, lightest weight, ophthalmic...

    1) Lowest density, lightest weight, ophthalmic lens available.
    2) The only ophthalmic lens that doesn't chip or crack.

    Need more proof?

    Low chromatic aberration, high strength, available in...
  5. The chart above is for HOAs. The way I read it,...

    The chart above is for HOAs. The way I read it, it's only the 2nd and 4th order aberrations that are affected by panto tilt. That's good because spherical aberration is generally not a problem for...
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    Tia, Check medical history. If it happens w/o...

    Tia,

    Check medical history. If it happens w/o eyeglasses see a GP or ENT doc. Otherwise PAL design, probably too hard/fast/strong. Will probably do some or most extended close tasks w/o...
  7. The slightly soft acuities, a somewhat unusual...

    The slightly soft acuities, a somewhat unusual add for their age (unless they have pseudophakic eyes), the .12 distance power cut, and the PAL design change might mean something. Did you get the...
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    The Band - The Weight 1970 Where are the young...

    The Band - The Weight 1970

    Where are the young composers?


    https://www.youtube.com/watch?v=N79OAlMi2nI
  9. Welcome to Optiboard. Thanks for including a...

    Welcome to Optiboard. Thanks for including a fairly thorough history. Including the client age, acuities, and pupil heights would help us tremendously for a proper troubleshoot.

    The red flag that...
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    We can get Zeiss PALs in the US. I looked at...

    We can get Zeiss PALs in the US.

    I looked at Rodenstock frames a few weeks ago. They were contemporary in appearance, and sensibly engineered. I didn't ask if their lens division is re-entering...
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    There are only two ophthalmic lens materials that...

    There are only two ophthalmic lens materials that have an Abbe value in the mid/high 50's, crown glass (59v) and hard resin cr39 (58v). If it is cr39, the refractive index and density should be...
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    No dumb questions, just dumb answers. ...

    No dumb questions, just dumb answers.

    Moreover, you make us think about what else yoked prism can do, bad or good. For example, it changes our perception, enough that we might not want to use it...
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    Jimi Hendrix - Foxy Lady 1968 Aw shucks, foxy...

    Jimi Hendrix - Foxy Lady 1968

    Aw shucks, foxy lady!


    https://www.youtube.com/watch?v=_PVjcIO4MT4
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    Two prism diopters worth, equal to about .6mm of...

    Two prism diopters worth, equal to about .6mm of displacement.

    Frame shape is a different issue, and primarily for variable corridors only. PALs designs might use one, both, or neither...
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    A short eyewear wearing history, resulting in...

    A short eyewear wearing history, resulting in greater sensitivity to magnification and narrowed fields of vision, compared to emmetropes and especially myopes, and less motivation due to good...
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    Most have a very short eyeglasses wearing history...

    Most have a very short eyeglasses wearing history and hate eyeglasses. Watch out for displaced aggression.

    Hone your skills.

    Demonstrate the alternatives (SVDO/SVNO, segmented multifocals,...
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    That might not be aspheric, and it has to be, or...

    That might not be aspheric, and it has to be, or the near and peripheral vision will be poor. Short of CLs, the best spectacle lens for acuity will be the Essilor Super Modular. Keep the decentration...
  18. Keep in mind that the difference in thickness due...

    Keep in mind that the difference in thickness due only to refractive index between 1.60 and 1.67 is only ((1.60 - 1.00) / (1.67 - 1.00) = 0.90) 10% thinner.

    As stated, it's semi-finished, meaning...
  19. About 3% to 5% more (compared to front aspherics)...

    About 3% to 5% more (compared to front aspherics) according to D. Meister's Optical Analysis program. A tad more for high minus (>8 D), without lenticulation.

    Puck, semi-finished, same animal....
  20. The biggest concern I have with this Rx is...

    The biggest concern I have with this Rx is positioning the vertical OCs to minimize vertical prism imbalance due to anisometropia.

    Due to budget constraints that you described, and the above...
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    The Specials - Too Much Too Young 1980 My...

    The Specials - Too Much Too Young 1980

    My neighborhood is packed with young married couples and their children.

    They could be having fun.


    https://www.youtube.com/watch?v=bwkPePoS23E
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    Optical24/7's ABOM topic was on Hemianopia. ...

    Optical24/7's ABOM topic was on Hemianopia.

    Hope this helps,

    Robert Martellaro
  23. I've been listening to politicians so much lately...

    I've been listening to politicians so much lately that I'm beginning talk like them.
  24. A significant decrease the wrap angle after...

    A significant decrease the wrap angle after insertion, possibly due to flat BCs, should increase the temple spread angle (outwards). The opposite is true for steeper BCs, which I see much more...
  25. Not the same. Yup. All powers would have...

    Not the same.

    Yup.

    All powers would have flatter BCs. We'll probably have better results if we aphericize the meatiest curve, that is, the ocular curve for minus, and the BC for plus. But it's...
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