Patient with presbyopia / One Rx, Two frames.

[rinselberg]

For-Life... Vx Panamic now is light years better than the original, the V2, the infinity or the Comfort. Zeiss, Rodenstock, and Definity have nice designs. But, our clients like polaraized sun lenses and Crizal AR, and Transitions, and 1.67 index, etc. it's about product diversity as much as design. So, if you know the pt. wants polar suns, why fit them in a lens design that would be different in his regular glasses? it is just much better if they have the same design in all their glasses.

I have a tech question for the PRO's (or anyone else) to weigh in on. It is not a question with an exact, numerical or provable answer, but there may be some general answers. The patient wants two frames with PALs, one for general use and a second one as a spare or for occasional use, or for highway driving and sunwear use. If the indispensable objective is to avoid any stress or accommodation times when changing from one frame to the other, the obvious answer is to use the same frame model and size, the same lens brand and lens design (like Panamic), and the same lens material, or at least have the lens materials be as similar as possible, aside from tinting or polarization that would be used for visible light management (= sunglasses!). But the patient wants to use two different looking frames for cosmetic reasons or because (like me) they think that having two different looking frames will better satisfy their "consumer cravings".

I have an uneducated guess: That even small differences in frame dimensions and angles, curvatures of the lenses and the "faceform" factors (maybe that last term is redundant) are going to largely outweigh any diffences from one PAL to another. So that the patient who wants to have two different looking frames could get the same PAL or a different PAL from one frame to the other, and that it would not make much difference either way as far as the PALs.

I also have another uneducated guess: That empirical data based on customer feedback will have more to say about this question than predictive data based on scientific analyses of PAL designs. But as for you optical scientists, please do not hesitate to "wax theoretically".

Ronald Inselberg
eye patient / Rx lens user

[Chris Ryser]

if you give the patient the same PAL's in each frame, but watch out that you give him the same size (height) frame, even if they are different models. Also make sure you measure and apply the correct monocular PD.

[rinselberg]

I have an uneducated guess: That even small differences in frame dimensions and angles, curvatures of the lenses and the "faceform" factors (maybe that last term is redundant) are going to largely outweigh any diffences from one PAL to another. So that the patient who wants to have two different looking frames could get the same PAL or a different PAL from one frame to the other, and that it would not make much difference either way as far as the PALs.

I would like to restate that question from my thread starter to make it more understandable:

I have an uneducated guess: That even modest differences from one frame to the other in terms of the frame dimensions and angles, base curvatures and the "faceform" factors (maybe that last term is redundant) are likely to outweigh (as a determinant or driver of stress and/or readaption times when switching between the frames) any and all identities (or equalities) that are realized by having identical PALs (or as identical as possible, given that one of the PALs has to be compatible with whatever mirrors, tints or polarization are wanted for sun protection), from one frame to the other.

How's that? Clear enough? The same way that Donald Rumsfeld would have stated this question?

[drk]

That's a question worthy of a person in the profession. Good question.

I would say, generally, you are correct, and maybe my point is slightly more theoretical than practical, but if the goal is to minimize the difference between the two glasses, keeping the lens design the same will be one more factor towards that goal. I always try to do what the Ranger does, and I'm a Fanamic, too.

[Texas Ranger]

Actually, I think that the more you change the frame design, the more critical it becomes to maintain the same optics,i.e the same pal design. Example, before Varilux made the Comfort design available in polarized blanks, patients that demanded pal polarized sun lenses, but wore a Vx Comfort in their clear glasses, we'd put a KBCO lens in their sun lenses, with obvious dissatisfaction. the myopes "tolerated" the difference, just knowing that it had to be different, but the presbyopes were very upset at the difference...matching base curves and prism thinning are also major factors too. I do have many clients who have multiple pairs of glasses, and it is so important that 1) lenses design,2) base curves, 3) prism thinning, 4) monocular pds and seg hts. all match. the frame styles can all be quite varied, but not the optics...

[rinselberg]

I have an uneducated guess: That even modest differences from one frame to the other in terms of the frame dimensions and angles, base curvatures and the "faceform" factors (maybe that last term is redundant) are likely to outweigh (as a determinant or driver of stress and/or readaption times when switching between the frames) any and all identities (or equalities) that are realized by having identical PALs (or as identical as possible, given that one of the PALs has to be compatible with whatever mirrors, tints or polarization are wanted for sun protection), from one frame to the other.

I restate my restatement:

As a determinant or driver of stress and/or readaption times when switching from the wearing of one model of frame to another, even modest differences in frame dimensions and angles, base curvatures and "faceform" factors (that may be redundant) are likely to outweigh any and all optical identities (equalities) that could be realized by purposely selecting the same PAL design and the same or similar lens materials for both frames.

[drk]

If you state it that way: which is more of an issue, matching progressive designs or matching frame characteristics, I agree that frame characteristics have the potential greater impact, since there is such variation in frames, whereas lens designs are relatively less variable.

[For-Life]

I just want to say that since I was invovled in the quote I just want to make sure it was clear what I said and not to be taken out of context. My statement was refering to the differences between the popular "best" or high end progressives like the Sola One or the Varilux Panamic, not the difference between the Panamic and V2.

Saying that I do want to say that many times I have done one dress pair in the Panamic and the sunglass in the Super No Line, and have had no problems. Additionally, two years later I will repeat what I did the first time with the same customer. I do explain to the customer what I am doing and why I am doing it, and they are always quite happy. There are some patients that are very picky that any changes in the bc, lens type, or as you suggested, frame can make all of the difference in the world; however, those affected by it are, in my opinion, a very small percentage of the market.

[chip anderson]

Look I do this all the time and with the exception of one little old lady who complains of glare off her flat tops on one eye only, I have made the sunglasses in straight top, the clear glasses in progresssive, made the sunglasses in S-V with no concideration to base, brand, or anything other than seg.hts, useage, P.D.'s, and the usual things I would do if I were doing each job with no knowledge of the patient's previous glasses, or the auxillary pair.

No problems,

Don't try to make life rocket science when wood shop will do.

Chip

[Chris Ryser]

No problems,

Don't try to make life rocket science when wood shop will do.

Chip

I think I will not have to comment on Chip's remark because it makes all sense.

It looks like we should start a new thread discussing left or right handed screw drivers.:hammer: :hammer:

[rinselberg]

...There are some patients that are very picky that any changes in the bc, lens type, or as you suggested, frame can make all of the difference in the world; however, those affected by it are, in my opinion, a very small percentage of the market.

Thank you For-Life.

What is "bc" please?

[For-Life]

Sorry bc = base curve.

[mrba]

It has been my expirience that adaptation is a purely psychological thing. If you tell a patient they will have to work hard to get used to something different, then, they will work hard and be able to adapt with ease. If you don't tell them anything is different, again they will minimize the differences in their mind and adapt with ease. I have many patients in multiple lens desighns that notice nothing. One classic example that everyone expiriences is a different desighn for a polar PAL vs a clear. We do this all of the time without problem.


I must say, the baggage that people have from dispensing older PAL desighns, especially from the 80's never fails to blow me away.

I would say the biggest obstical hands down is always the psychology of the dispensor!

[For-Life]

It has been my expirience that adaptation is a purely psychological thing. If you tell a patient they will have to work hard to get used to something different, then, they will work hard and be able to adapt with ease. If you don't tell them anything is different, again they will minimize the differences in their mind and adapt with ease. I have many patients in multiple lens desighns that notice nothing. One classic example that everyone expiriences is a different desighn for a polar PAL vs a clear. We do this all of the time without problem.


I must say, the baggage that people have from dispensing older PAL desighns, especially from the 80's never fails to blow me away.

I would say the biggest obstical hands down is always the psychology of the dispensor!

I agree. This is why I put all new presbo's in PAL's, and how I figure out if a flat top or trifocal patient would be able to go into a PAL or not. If someone comes into my practice with a flat top and they say that they hate the line and they hate that they get no intermediate then I know that they will be motivated enough to have no problem going into a PAL. However, if someone has been wearing a flat top for 30 years and has no reason to go into a PAL they probably will not give it a chance and you will have a non-adapt. If they want to go into a PAL they will have no trouble, if they don't want to your in a lot of trouble.

[Clive Noble]

In my experience, it all depends on the patient and his/her tolerance level of acceptance.

We've had one recently in Clear Natural CR with AR, a second pair also Natural, no AR but 70% Full grey, similar size frame, same Base curve, same PDs but not able to wear the sun specs.......headaches. Maybe it's the lack of AR?

Another one in Gradal Top, clear with Carat SET on a 4 base, smallish frame, recently made a large 'wrap-round' 8 base Sola XL with dark tints....... absolutely delighted, the comment I got was "Why did I pay the extra for the Zeiss? The cheaper Sola's do the same job!!

Go figure, but as has already been stated, the important points are Base Curves, Mono PDs, and similar Equithin Prism

[Andrew Weiss]

I wear several different progressives: a Rodenstock Life 2 Colormatic (1.52) in a Silhouette semi-rimless; a Rodenstock XS 1.6 in a Kenneth Cole semi-rimless; a Zeiss Short-I 1.6 in a Grant metal; a Nikon i13 1.67 in another Grant metal; and (most recently) a Nikon OnLine 1.67 in a Vanni zyl. All of the frame dimensions are different. Only two sets of lenses are made by the same manufacturers and therefore should have similar front-surface characteristics. I have no problem adapting from one to the other; the longest adjustment time is switching to the Nikon, and I suspect that's in part due to the 1.67 material, not just the PAL design.

On the other hand, we have a patient in our office for whom we just redid a Zeiss Top. His new glasses are identical in virtually all respects to the old ones -- same power, same PAL, same lens material, same PDs, same height relative to pupil, similar vertex and panto, same prism thinning, same lens thickness, similar frame dimensions -- but he didn't see as well out of them as he does out of his old ones! Our office tends to get more than our share of sensitive patients, and for those folks, ANY change is problemmatic, whether it's frame dimensions, progressive design, lens material, base curve, PDs, heights, etc. etc.

We can say that this is psychological, but it's not something that we can cure. Those patients with greater sensitivity will always be less tolerant of variation.

So I can't come up with a general answer to this question. My best answer would be, "it depends . . ."

[Texas Ranger]

of course this is good discussion, and since i've pretty much just fit one or two different pals for the last 25 years, it's pretty easy for me to think that pts have probelms when they switch from one pal design to another, because sometimes that also requires a base curve changem i.e. even going from a Vx Comfort to a Vx Panamic can be a base curve problem. the question is, why change them? and run the risk of them being "sensitive". They do need to be warned in advance if there is going to be something potentially different in an alternate pair of lenses. Those folks that come in wearing a Kodak pal that's fit 5-6 mm above the pupil for 2 years, and had a "hard time adjusting" to them, are not my normal pt. I could probably fit those folks with any pal design, and estimate the pds and seg hts and they'd be fine, but unfortunately, my clients are engineers, airline pilots, etc; picky people...they expect the very best, and expect that they should see the same with all of their glasses; I figure that the fellow whose regular rx is a Zeiss pal on a 4 bc, and got a SNL on an 8bc, and is happy, is not the normal pt. probably had a high priority for those wrap SGs? I am bnot in the group that thinks "it's all in their heads"...like the lady that went back and forth between 3 MDs, who all just wanted to blame her visiual discomfort on the lenses, finally found another doc, and found that she had had a retinal stroke in the bothersome eye that 3 MDs couldn't find; pretty amazing. she isn't much happier other than she know what her problem is and can watch other aspects of her overall health...the problem wasn't psychological, it was physiological, wasn't optical either. peoples vision problem are not always about the phoropter and the pal design...

[Andrew Weiss]

TR, I don't want to give the impression that I change people out of one type of progressive to another regularly or easily. I will also keep patients in what they've been wearing, although this becomes challenging when they've been wearing, say, a VIP and want a frame which gives, at best, an 18mm fitting height. I try to steer patients who have been wearing progressives for some time away from frames that will not accomidate their lenses at the suggested fitting height. The same is true of lens materials: we still have some patients whom we keep in glass at their request.

We also have a fair number of engineers and other professionals in our patient base. They want the best, sure. Sometimes they're not wearing "the best", but I won't change them into something else unless either (a) they complain about their progressive and I see that a change in lens design will likely solve their problem, or (b) they are certain they want a frame with a shorter fitting height, in which case I explain, in whatever detail the patient can understand, the differences between their old progressives and the new ones I'm suggesting, and let them choose. Sometimes the patient chooses to change the progressive, sometimes they look for a different frame.