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Thread: Which PAL is better and why

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    Which PAL is better and why

    Cast molded front PAL with a "digitally enhanced" back-side surface or a fully free-form (design+RX) on a spherical SV blank.

    No necessarily interested in discussing Camber technology.

    Looking to become less ignorant on the subject, thanks in advance for any input.
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    I prefer Free Form; Shamir In Touch or Autograph III compensated, Zeiss Individual 2 compensated. Full Rx on the ocular surface of the lens means a more direct access to the Rx. I never liked the dual add designs. Aspheric front for an atoric design.
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    Exactly the point Scriptfiller!! You got it! We devolped Camber to somewhat "mimic" the natural curve of a progressive lens which curves naturally as the power changes! E Mail me at drips@youngeroptics.com and I will fix you up with a free pair of Drivewear!

    ps. A front side progressive with a properly designed backside design is indeed a very good lens!

  4. #4
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    Rx and lens design determine what is best, but they have to match the use of the lens, also.

    A Zeiss Individual 2 will out WOW anybody more than anything else (if fit properly and worn in various lighting conditions). You MUST understand that "digital" means nothing in terms of performance. A lens is only as good as the math behind it, and that math is patented.

    However, when someone just needs something to use in the garage in their safety frame and doesn't want to spend a ton of money and wants something safe, Zeiss Individual 2 is over kill.

    An increase in performance (reduction of unwanted astig) of a bad lens design still makes a bad lens design. You want a lens that adapts to your patient, not a product that your patient has to "learn to wear."

    I hope that helps!

    P.S. A direct answer to your question is that full free-form technology CAN out perform any molded product, partially molded or otherwise.

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    Also I have read that its not a perfect alignment if there is a corridor on the front, then you go to add it to the back and can be off at time a lill due to mounting, and it compromises the whole deal. Free form does it all at once. Hope I am saying that correct.

    I need to try one of those cambers... just love the idea behind it.

  6. #6
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    Quote Originally Posted by ThatOneGuy View Post
    Rx and lens design determine what is best, but they have to match the use of the lens, also.

    A Zeiss Individual 2 will out WOW anybody more than anything else (if fit properly and worn in various lighting conditions). You MUST understand that "digital" means nothing in terms of performance. A lens is only as good as the math behind it, and that math is patented.

    However, when someone just needs something to use in the garage in their safety frame and doesn't want to spend a ton of money and wants something safe, Zeiss Individual 2 is over kill.

    An increase in performance (reduction of unwanted astig) of a bad lens design still makes a bad lens design. You want a lens that adapts to your patient, not a product that your patient has to "learn to wear."

    I hope that helps!

    P.S. A direct answer to your question is that full free-form technology CAN out perform any molded product, partially molded or otherwise.
    I'm going to disagree a little on the wow factor of a single lens used for all applications.

    There are two main advantages, from a dispenser and patient standpoint about a digitally processed lens.
    One is accuracy, with any molded progressive, you have a very complex lens geometry that is being molded to a tolerance which is a lot larger than what a digital generator can achieve.
    Also, most molded progressives are processed by conventional surfacing, which also has a tolerance a lot larger than a digital generator.

    The second is, for myopic patients, it brings the add closer to the eye with less pantoscopic frame tilt, creating a better F number per say.
    By having the full complex surface on the rear, you also eliminate the transition areas of diverging and converging surfaces relative to the front and rear surfaces.


    Quote Originally Posted by Slim View Post
    Also I have read that its not a perfect alignment if there is a corridor on the front, then you go to add it to the back and can be off at time a lill due to mounting, and it compromises the whole deal. Free form does it all at once. Hope I am saying that correct.

    I need to try one of those cambers... just love the idea behind it.
    If you've ever finished blocked a lens, you know it's not easy to get things perfectly aligned. Surface blocking a front side molded PAL is just a difficult.
    By putting the complex surface on the rear, surface blocking becomes almost as easy as finish blocking a plano FSV lens.


    The great thing about the camber lens, from a lab/optics standpoint, aside from hitting ideal base curve for every section of the lens.

    Is, because its still horizontally spherical, you have no transition areas of converging and diverging curves, front to rear surface relative.
    It also makes it a little easier to surface block, there by increasing processing accuracy.

    Hope that helps a little.

  7. #7
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    Quote Originally Posted by ml43 View Post
    I'm going to disagree a little on the wow factor of a single lens used for all applications.
    The emphasis is that the one product will wow more consistently than any other one product.

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    Quote Originally Posted by ThatOneGuy View Post
    The emphasis is that the one product will wow more consistently than any other one product.
    Thats actually exactly what I am going to disagree with a little.

    There is no single design that is optimized for every single persons needs.

    Even with the individual 2's custom parameters, there are still other designs that will be beter based on a wide variety of variables.

  9. #9
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    Quote Originally Posted by ml43 View Post
    Thats actually exactly what I am going to disagree with a little.

    There is no single design that is optimized for every single persons needs.

    Even with the individual 2's custom parameters, there are still other designs that will be beter based on a wide variety of variables.
    Which variables that the Individual 2 doesn't account for?

  10. #10
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    Quote Originally Posted by scriptfiller View Post
    Cast molded front PAL with a "digitally enhanced" back-side surface or a fully free-form (design+RX) on a spherical SV blank.
    Which PAL is better and why? Either design can be good or bad, but at their best (advanced software derived from wearer trials, ophthalmic optical/differential geometric science, fully optimized/ customized for the Rx and fitting parameters), a back-side PAL will provide the intended progressive design over a wider range prescriptions and fitting values.

    Note: Zeiss owns the patent for back-side PALs on a rotationally symmetric front-side. If you put all of the add on the front, spilt the add from to back, or use a single vision aspheric front-side, you won't have to pay a royalty fee.

    http://www.opticampus.com/files/optics_of_free-form_lenses.pdf
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  11. #11
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    Quote Originally Posted by Robert Martellaro View Post
    Note: Zeiss owns the patent for back-side PALs on a rotationally symmetric front-side. If you put all of the add on the front, spilt the add from to back, or use a single vision aspheric front-side, you won't have to pay a royalty fee.

    http://www.opticampus.com/files/optics_of_free-form_lenses.pdf
    Right. If memory is serving, then Hoya owns the split add concept and Seiko owns the aspheric SV. I haven't looked to see if Camber falls under Seiko or Hoya, or if they were able to make a big enough difference to negate either obligation.

    Regardless, any time you have a molded front PAL of any amount, you are limited in the range of customization available with a given rx, so backside is always going to be more capable of being better, though molded has potential to do well if rx and wearer habits are perfect.

  12. #12
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    Quote Originally Posted by ThatOneGuy View Post
    Right. If memory is serving, then Hoya owns the split add concept and Seiko owns the aspheric SV. I haven't looked to see if Camber falls under Seiko or Hoya, or if they were able to make a big enough difference to negate either obligation.
    WRT back-side PALs, there are cross licensing agreements between Zeiss and Seiko. Hoya licensed the technology about the same time that Signet Armorlite (Essilor) lost a patent infringement suit vs Zeiss.

    http://www.visionmonday.com/latest-n...ologies-36417/
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  13. #13
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    Quote Originally Posted by ThatOneGuy View Post
    Which variables that the Individual 2 doesn't account for?
    Patient intended use, ideal base curve for every rx along the lens/corridor, base curve compensation when specified

    Remember, the individual 2 only comes in 3 or so designs, and all have the same corridor shape(area's of high astigmatism)

    If you compared the individual 2 to something like a Surmount, or a Superior. It's not better, it's just different.
    Same could be said for the camber, in the various designs it comes in.

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    Quote Originally Posted by Paul Smith LDO View Post
    I prefer Free Form; Shamir In Touch or Autograph III compensated, Zeiss Individual 2 compensated. Full Rx on the ocular surface of the lens means a more direct access to the Rx. I never liked the dual add designs. Aspheric front for an atoric design.
    Not exactly related to the OP's original question - but how do you present the benefits of the In Touch as opposed to the Auto III? How do you explain it to the client?

    Or do you? And if not - which do you choose for what types of RX's/needs? Thx

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    Quote Originally Posted by Tallboy View Post
    Not exactly related to the OP's original question - but how do you present the benefits of the In Touch as opposed to the Auto III? How do you explain it to the client?

    Or do you? And if not - which do you choose for what types of RX's/needs? Thx
    I use the In Touch as my everyday work horse, for those patients of mine who work at a desk and are using a lap top or a smaller monitor and have never worn a FF design. For my patients who have been wearing a FF and are requiring > 2.50 ADD I have been putting them into the AUTO III. For those patients who have had some issues with Shamir products in the past or who just want a little sharper vision I will put them into the Individual 2.
    I have been a big fan of Shamir for about 12 years, I really love the In Touch but the Individual 2 is a stellar lens and I been very pleased with it's performance.
    Cheers
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    A long-shot here, so, Auto III better than Varilux S?

    I was thinking a mash-up between a cast mold front and embellishing it with a pseudo freeform backside treatment is asking for trouble and/or expense?
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    Quote Originally Posted by scriptfiller View Post
    A long-shot here, so, Auto III better than Varilux S?

    I was thinking a mash-up between a cast mold front and embellishing it with a pseudo freeform backside treatment is asking for trouble and/or expense?
    An increased "keyhole" with the Free Form when compared to the dual design and the Auto III is a compensated design. The other thing to consider is what the patient is currently wearing and how well are they doing with it. Switching the design may require a period of adaptation, if the patient has several pairs it may be prudent to keep them a similar design or collect all their glasses until the make the adjustment.
    I didn't attend the funeral, but I sent a nice letter saying I approved of it. Mark Twain

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    Remember to take POW measurements for Individual 2 and other free Form backside PALS or you totally miss the benefit of their design. We've seen a few remakes simply because of this neglect and default Panto , for example, was way off from the actual Panto.

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    Quote Originally Posted by ml43 View Post
    Patient intended use, ideal base curve for every rx along the lens/corridor, base curve compensation when specified

    Remember, the individual 2 only comes in 3 or so designs, and all have the same corridor shape(area's of high astigmatism)

    If you compared the individual 2 to something like a Surmount, or a Superior. It's not better, it's just different.
    Same could be said for the camber, in the various designs it comes in.
    I'm afraid you are misinformed.

    Patient intended use: The Individual 2 comes in three designs. They are the 2, 2i, and 2n. Which design you use is selected based on the patient's intended use.

    Ideal BC along the corridor: While this is technically accurate that the Individual 2 is not a Camber lens, it is also only one issue in the myriad issues that exist in progressive lens design.

    Base Curve Compensation: I'm not sure what you are getting at specifically, here, but the Individual is available in a wrap, and you can specify BC within particular ranges based on Rx.

    Individual 2 only in 3 designs: That is simply false. Individual 2 is an algorithm that changes the lens design (not the compensation for a lens design) based on the given parameters of Rx, frame size/shape, near/dist PD, pupil size, POW, near object distance. Further more, the 2i and 2n allow for modifications of that algorithm to account for intended use. Said another way, the Individual 2 is not a lens design, so much as it is a lens design philosophy that is then implemented in the individual creation of a lens.

    Comparing products: In the age of molded progressive lenses, you are exactly correct that some lenses work better for people than others. However, the Individual 2 is not molded, nor is it a design. It is an algorithm that can adjust based on the specific variables you are describing, creating (as they said in their little video when the Individual came out) a lens as unique as you.

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    Quote Originally Posted by ThatOneGuy View Post
    I'm afraid you are misinformed.

    Patient intended use: The Individual 2 comes in three designs. They are the 2, 2i, and 2n. Which design you use is selected based on the patient's intended use.

    Ideal BC along the corridor: While this is technically accurate that the Individual 2 is not a Camber lens, it is also only one issue in the myriad issues that exist in progressive lens design.

    Base Curve Compensation: I'm not sure what you are getting at specifically, here, but the Individual is available in a wrap, and you can specify BC within particular ranges based on Rx.

    Individual 2 only in 3 designs: That is simply false. Individual 2 is an algorithm that changes the lens design (not the compensation for a lens design) based on the given parameters of Rx, frame size/shape, near/dist PD, pupil size, POW, near object distance. Further more, the 2i and 2n allow for modifications of that algorithm to account for intended use. Said another way, the Individual 2 is not a lens design, so much as it is a lens design philosophy that is then implemented in the individual creation of a lens.

    Comparing products: In the age of molded progressive lenses, you are exactly correct that some lenses work better for people than others. However, the Individual 2 is not molded, nor is it a design. It is an algorithm that can adjust based on the specific variables you are describing, creating (as they said in their little video when the Individual came out) a lens as unique as you.
    My statements are not based on information that is being handed to me, but by lens modeling software and a little calculus/differential geometry
    for the most part, decently basic geometric optics.

    Like I stated before, the individual 2 does come in different designs, but they all have very similar areas of high astigmatism.
    None of which can model something like a camber or a surmount.

    base curve compensation is a variant on the conic constant to achieve the same performance given non ideal base curves, in general, zeiss designs don't handle this as well as say, Shamir or IOT.

    I believe you and I are comparing two different things.


    What I am saying, is there is an infinite amount of ways to blend two complex surfaces/radius's of curvature.
    All variations will have unintended astigmatism and/or discontinuity.
    To say that one "design/algorithm/lens" does this better for every single person,
    than any other of the infinite amount of other possibilities is what I am disagreeing with.


    Hope that makes sense

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    Quote Originally Posted by ml43 View Post
    My statements are not based on information that is being handed to me, but by lens modeling software and a little calculus/differential geometry
    for the most part, decently basic geometric optics.

    Like I stated before, the individual 2 does come in different designs, but they all have very similar areas of high astigmatism.
    None of which can model something like a camber or a surmount.

    base curve compensation is a variant on the conic constant to achieve the same performance given non ideal base curves, in general, zeiss designs don't handle this as well as say, Shamir or IOT.

    I believe you and I are comparing two different things.


    What I am saying, is there is an infinite amount of ways to blend two complex surfaces/radius's of curvature.
    All variations will have unintended astigmatism and/or discontinuity.
    To say that one "design/algorithm/lens" does this better for every single person,
    than any other of the infinite amount of other possibilities is what I am disagreeing with.


    Hope that makes sense
    I'm understanding your argument, just disagreeing with it.

    What I disagree with is the idea that the strength of astigmatic error is as relevant as the placement of that error.

    Zeiss patented what they marketed as "Horizontal Symmetry," some time ago. As I understand it, that patent expired recently at which point Essilor came to market with what they called "Nanoptics." The concept is to basically allow both eyes to see the same amount of distortion so that the brain can ultimately adapt so the patient perceives little to no distortion.

    Zeiss technologies all focus on the ability to accurately focus light at a desired point. It is why people love their optics when it comes to camera lenses, rifle scopes, microscopes, etc. That is a very different perspective from what I see any of the other manufacturers doing. Shamir went the route of simply offering a massive amount of lens designs under the banner of one brand (Autograph III, Autograph Fashion, etc.). Hoya went the route of producing massive quantities of lens blanks to get closer to providing better optics under the guise of choice. Essilor has gone the route of branding, enhancing, rebranding, enhancing, rebranding. IOT seems to have borrowed from Hoya's concepts of molded fronts with split powers and provided a weird shaped blank in order to avoid patent disputes.

    I don't dispute that IOT or Hoya can provide a wider field of view compared to a standard Individual 2 in the intermediate or near, I just liken it to a D35 vs D28. 99.99% of patients don't need or desire a D35 because the D28 provides adequate width for where they actually look.

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    Quote Originally Posted by scriptfiller View Post
    A long-shot here, so, Auto III better than Varilux S?

    I was thinking a mash-up between a cast mold front and embellishing it with a pseudo freeform backside treatment is asking for trouble and/or expense?
    I have great success with Varilux lenses. Not the S though, I have MUCH more success with the Auto III than most other lenses, and most certainly more success with the AutoIII than over the S.

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    Thanks to all who contributed!
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