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Thread: PAL recommendations for a hyperope needed

  1. #1
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    Lightbulb PAL recommendations for a hyperope needed

    I would appreciate your PAL recommendations for a moderate plus Rx:
    (R) +5.25 / -1.75 x 90 / add 1.75
    (L) +3.75 / -1.00 x 83 / add 1.75
    The lenses will be going in a full-size frame with a B-height of 35+ mm, so a short corridor design is not needed.

    Which lenses use split designs and are NOT totally backside surfaced?
    Which lenses have you had great adaptation success with for plus Rx patients?
    Which lenses in a plus Rx have the widest corridor in distance, intermediate and reading?

    Prescription powers above +3.00 D represent a small percentage of lens sales, so PAL designs tend to be myope-biased. But a hyperopic patient put in the wrong lens design makes for an unhappy patient, optician, and lab. Our PT had been in Nikon SeeMax PALs with great success, but experienced adaptation problems when Nikon switched to a more backsided design in 2010. [Earlier SeeMax lenses had a very complex front surface geometry (think “fun house mirror” curvature), while the new-style Seemax lenses appear to have a factory-molded spherical front.] A change in Abbe value may have also contributed to non-adaptation--the last lenses dispensed used 1.67 index material to cut weight through thickness reduction (prior lenses were 1.60).

    This forum has widely scattered and some outdated recommendations for plus Rx PALs. It would be nice to keep a thread updated with current lens choice recommendations as new products are introduced or old ones redesigned.
    Last edited by Prince Nez; 01-23-2013 at 11:57 PM.

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    Except to correct or add to a few statements, I'll speak in generalities only- it seems likely that you are the client, which, on this forum, forbids me from providing medical or technical advice.

    The old-style SeeMax lens had a very complex front surface geometry (think “fun house mirror” curvature)
    Yes, the progressive optics are on the front of the lens.

    used 1.67 index material to cut weight (prior lenses were 1.60)
    The weight will be the same. Moreover, if the 1.60 refractive index lens was Finalite, it would have been be lighter in weight than 1.67!

    Do not concentrate on lens brand, manufacturer, or progressive design. Find an experienced, advanced or master level optician. They'll be able to explain what can, and can not be done. They will realistically manage expectations, and get it right the first time.
    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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    Biting tongue...
    Last edited by Prince Nez; 01-25-2013 at 02:13 PM.

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    Respectfully submitted...

    Except to correct or add to a few statements, I'll speak in generalities only- it seems likely that you are the client, which, on this forum, forbids me from providing medical or technical advice.
    Thanks for your gracious reply. Actually, I'm a vendor, and my customer is a very capable optician. But I may be biased -- he sells our products. He's also very busy because he is so good, and has not been able to research what lenses would work best for his PT in the frames we picked out. I offered to help because its good business and good Karma. I posted my questions to Optiboard based on the collegiality and professionalism of the responses I had previously read.

    Yes, the progressive optics are on the front of the lens.
    Not always. That was the point of my post. Darryl Meister explained HERE in 20/20 Magazine that common free-form progressive lenses are available in three different configurations, and the progressive optics may NOT be on the front of the lens. 
"Back-surface lenses employ a factory-molded spherical front and a free-form-surfaced progressive back surface that has been combined with the prescription curves; the progressive optics are directly surfaced. Enhanced semi-finished lenses employ a factory-molded progressive surface on the front and free-form surfaced prescription curves that have been optically optimized on the back; the progressive optics are factory-molded. Dual-surface lenses employ a factory-molded progressive surface with a portion of the total addition power on the front and a free-form surfaced progressive surface with the remaining addition power that has been combined with the prescription curves on the back; the progressive optics are split between both lens surfaces."


    The weight will be the same. Moreover, if the 1.60 refractive index lens was Finalite, it would have been be lighter in weight than 1.67!
    Maybe, maybe not. The overall weight of the finished eyewear depends in part on the index of the material selected in concert with the particular mounting system used. Higher index material will generally weigh more than lower index material. Higher index plastic is more dense, and that density (weight per volume) is often higher than a lower index plastic, such as in the example between 1.60 Finalite vs. 1.67. Ideally, any weight gained using a higher index plastic will be offset by the overall reduction in lens thickness.

    A better example is how my customer's PT ended up with drill-throughs made out of 1.60 vs. Trivex. The dispenser used heavier 1.60 on this plus Rx, but then had to order non-optimized thicker blanks that would withstand the added stress of corner drilled temple holes. Think about that... Had the lenses been made in Trivex, there would have been no need to "reinforce" the corners by ordering thicker blanks because the Trivex would have been slightly thicker, but more importantly, a lot stronger and probably about 1/2 the weight. Instead, the PT ended up with heavy lenses that kept sliding down her nose (aka, not acceptable position of wear).

    Quote Originally Posted by Robert Martellaro View Post
    Do not concentrate on lens brand, manufacturer, or progressive design.
    Other posts in this forum have discussed the advantage if not necessity of using split PAL designs with hyperopes. In fact, HERE, you said "There are sound optical reasons to put the progressive optics on the front, especially for moderate to high plus." And HERE you said "A max power of +7.75 limits our choices significantly, especially if we use higher Abbe materials. I used to have a handful of clients with this type of Rx; the best results were when I used 1.60 refractive index Varilux Comfort (+8.37 true base curve) and Rodenstock's 1.60 Multigressiv. Those clients have passed, but for those with somewhat high plus, I'll use the Physio 1.60, and Hoya's MyStyle/InStyle 1.60/1.70, or 1.74 Zeiss Individual when thickness reduction is a priority."

    Hard to argue that it is unnecessary to concentrate on lends brand, manufacturer, or progressive design with plus patients when you do it yourself.

    Find an experienced, advanced or master level optician. They'll be able to explain what can, and can not be done. They will realistically manage expectations, and get it right the first time.
    Two dispensers didn't "get it right the first time" for my customer's PT. The real power of Optiboard is when colleagues choose to share information, all benefit.

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    Thanks to those who took the time to PM with suggestions.
    Last edited by Prince Nez; 01-25-2013 at 02:19 PM. Reason: duplicate in moderation

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    Quote Originally Posted by Prince Nez View Post
    Thanks to those who took the time to PM with suggestions.
    The Seiko Surmount works very well in the powers you indicate... its one of only 2 corridors that are individually optomize for each RX right now (Individual 2, is the other. Kodak Unique was, but I am unable to verify if that quality survived the redesign). Myopes and Hyperopes converge very differently because the effective prism created by the distance RX is very different. Most manufactures (about 98%) design corridors for myopes only, because there are far more of them. Only the Seiko and Individual 2 will realign the corridor calculating the needs of the individual RX at each point. The end result is that the eyes will have better binocular symmetry throughout the add, they simply will be better aligned and work together.

    We have not finished tesing the newer Individual 2 in enough Rx's for me to say its better in your power, but in theory in very high pluses, the Individual 2 begins to move some of the add to the front to keep the back from getting too flat. In theory the beneift would be seen aroud a +6, so you are close, but I can't verify at which powers Zeiss begins to move the add, and how much of it they move with the new design. Darryl Meister would be the person with those details. The Individual is a T-Shaped power design with a distance emphasis, where the Surmount is Barrel shaped with an Intermediate emphasis, so the lifestyle needs of your pat. may determine the best choice.

    It should be noted that both lenses require the Near mono PD for full advantage.

    Let us know what you decide, and how it works.
    Last edited by sharpstick777; 01-31-2013 at 11:54 AM.

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