Are we getting carried away?

[scriptfiller]

Digital lenses accurate to within 1/100th of a diopter...

I just had my Essilor rep in today pitching the new Physio Enhanced, supposedly it takes into consideration a given pupil diameter to optimize light transmittance...

Free-form this free-form that, thousands of free-form flavors...

I haven't matured yet to need PAL's yet but is there really, I MEAN REALLY, a noticeable difference between standard surfaced, digital surfaced and free-form produced PAL's. It seems that the industry is getting a little carried away.

[Now I See]

Someone (a rep) told me to think about music and how it has gone from records, to 8-tracks, to cassette tapes, then to CD's....still the same music, just a different delivery. ;)

**sigh** I wish I knew the answer to your question, the best advise I got when posing the same type of question was to remember that a progressive is still a progressive no matter how you cut it. :)

[Robert Martellaro]

Digital lenses accurate to within 1/100th of a diopter...

Not important.

I just had my Essilor rep in today pitching the new Physio Enhanced, supposedly it takes into consideration a given pupil diameter to optimize light transmittance...

The Physio is already enhanced for large pupils. If I feel it's necessary to try the new version I'll do so. If I can see a difference I'll let you know.

Free-form this free-form that, thousands of free-form flavors...

Where's the meat!

I haven't matured yet to need PAL's yet but is there really, I MEAN REALLY, a noticeable difference between standard surfaced, digital surfaced and free-form produced PAL's.

In some situations, yes. The lens I'm presently wearing uses this technology, and is giving me visual performance that has been unequaled by any other PAL design that I've tried.

That said, I would concentrate on getting the most appropriate design in front of your clients's eyes as possible, free-form/pow optimized or not. For some, that wil mean getting the distance zone as wide and as free of aberrations as possible, and still has a short enough corridor that minimzes posturing for those with Adds over +2.00. Others may do better with a very soft design and a longer corridor.

Sounds like you need a guinea pig.

It seems that the industry is getting a little carried away.

There's a strong push for market share. There are many advantages to eliminating semi-finished PALs from the loop. Prices will decline. The future is now.

[rbaker]

Digital lenses accurate to within 1/100th of a diopter...

I just had my Essilor rep in today pitching the new Physio Enhanced, supposedly it takes into consideration a given pupil diameter to optimize light transmittance...

Free-form this free-form that, thousands of free-form flavors...

I haven't matured yet to need PAL's yet but is there really, I MEAN REALLY, a noticeable difference between standard surfaced, digital surfaced and free-form produced PAL's. It seems that the industry is getting a little carried away.

It's the same as we used to do in the third grade school yard. My Wilie is bigger than your Willy! It's ad-speak to impress the uneducated. You have to try to distinguish your produce over all others even it it entails building a huge pile of horse pucky (as Col. Sherman T. Potter would say.)

There is an engineering concept called "appropriateness of scale" whch states that it is not necessary to increase the atomicity of a measurement system beyond the scale that is requires to complete the process. In plain English this is why carpenters do not use micrometers to frame a house.

[finefocus]

It's the same as we used to do in the third grade school yard. My Wilie is bigger than your Willy! It's ad-speak to impress the uneducated. You have to try to distinguish your produce over all others even it it entails building a huge pile of horse pucky (as Col. Sherman T. Potter would say.)

There is an engineering concept called "appropriateness of scale" whch states that it is not necessary to increase the atomicity of a measurement system beyond the scale that is requires to complete the process. In plain English this is why carpenters do not use micrometers to frame a house.

(1) Also, the doctrine of significant figures - no point in generating an answer accurate to 5 decimal points if the data was accurate to 2 decimals. An Rx written in 8th diopter steps is pushing it; 100th diopter steps are beyond the pale.

(2) I noticed a big difference with freeform PAL's, but not in what I saw; it's what I didn't see. Less of the usual side effects of PAL's, peripheral blur, small sweet spots, swimmy lower outside corners, etc.

[AWTECH]

Digital lenses accurate to within 1/100th of a diopter...

I just had my Essilor rep in today pitching the new Physio Enhanced, supposedly it takes into consideration a given pupil diameter to optimize light transmittance...

Free-form this free-form that, thousands of free-form flavors...

I haven't matured yet to need PAL's yet but is there really, I MEAN REALLY, a noticeable difference between standard surfaced, digital surfaced and free-form produced PAL's. It seems that the industry is getting a little carried away.

Do you recommend AR? Did you 10 years ago? The trend is toward more AR and the US is far behind Europe in percentage of AR sales. Even farther behind Japan.

Now Freeform which is newer than AR comes along and the trend is the same Japan as a percentage of jobs is way ahead, Europe is not quite as high, but much higher than the US. (All Freeform is not the same)

Less distortion is possible, Thinner lenses are possible, better overall performance. If the price for traditional vs. freeform was the same there would be no question.

[k12311997]

Do you recommend AR? Did you 10 years ago? The trend is toward more AR and the US is far behind Europe in percentage of AR sales. Even farther behind Japan.

Now Freeform which is newer than AR comes along and the trend is the same Japan as a percentage of jobs is way ahead, Europe is not quite as high, but much higher than the US. (All Freeform is not the same)

Less distortion is possible, Thinner lenses are possible, better overall performance. If the price for traditional vs. freeform was the same there would be no question.

In Europe and Japan glasses are fashion in America they are a medical device:hammer:. In Europe and Japan who needs free form for thinner lenses I've seen glasses from overseas with a .5 ct.

[AWTECH]

In Europe and Japan glasses are fashion in America they are a medical device:hammer:. In Europe and Japan who needs free form for thinner lenses I've seen glasses from overseas with a .5 ct.

Everyone is entitled to their opinion but I personally don't think in the US they are a medical device only, no more than they are in Japan and Europe.

As for Thinner lenses just by being 0.5mm CT is not always a good solution such a thin lens can be too flexible. In many cases especially with a PAL a good design freeform will be thinner. In most cases the optical performance will be superior due to managing power error and off axis astigmatism.

I think the Freeform Train has Left the Station

Like I said, if the same scipt could be had in conventional PAL or good design freeform why would you use traditional?

[k12311997]

that remark was public percption, not my opinion.

[AWTECH]

that remark was public percption, not my opinion.

If I understand what you are saying is that in America vs Europe and Japan we seem to be price is everything vs the ability to balance the true value. I often find myself looking at those low price ads on a product I know little about, then I catch myself and say what is the value of the purchase to me at the price offered.

[OCP]

Digital lenses accurate to within 1/100th of a diopter...

I just had my Essilor rep in today pitching the new Physio Enhanced, supposedly it takes into consideration a given pupil diameter to optimize light transmittance...

Free-form this free-form that, thousands of free-form flavors...

I haven't matured yet to need PAL's yet but is there really, I MEAN REALLY, a noticeable difference between standard surfaced, digital surfaced and free-form produced PAL's. It seems that the industry is getting a little carried away.

There IS actually a noticeable difference from conventional pals and freeforms, but as most of you know here, I agree that the industry are going way to far with all these trivial measures. "Pupil diameter". Come on. I´m sure Essilor could tell us a long prevarications of why this is important, and some will eat this history with skin and hair, but this has gone to far in my opinion.

Mike.

[Uilleann]

I'm certainly interested to learn more about what this lens claims it may do for my patients. And I'll happily put it to the test in the real world and see if there is an appreciable difference for my practice. Technology is advancing, and ophthalmic optics are not immune to advances as well. Ten years ago, I was quite content with my old 24" tube TV and VHS tape movies. Now, the 52" LED/LCD 1080P display makes my Blu-ray copy of the BBC documentary Planet Earth look frighteningly realistic and sharp. The difference is certainly a 'wow' type experience.

Will our humble little lenses ever deliver such an easily seen difference in the future? Who knows. But there is one certainly - the only guaranteed way to fail, is never to try. Give the new tech a shot. Educate yourself as much as you can - always ask lots of good questions (like this thread). You will be wiser for the knowledge and experience of it all...and may very well have an exceptional lens offering available at the end of the day.

Best!! :cheers::cheers::cheers:

[lind2020]

The U.S is behind foriegn countries in anti-reflective percentage because in the U.S. you have to pay for it.

Apples -vs- Apples please...


p.s. Perhaps obama's now defunct (or soon to be) plan may give U.S. residents free a/r also....

[AWTECH]

The U.S is behind foriegn countries in anti-reflective percentage because in the U.S. you have to pay for it.

Apples -vs- Apples please...


p.s. Perhaps obama's now defunct (or soon to be) plan may give U.S. residents free a/r also....

What countries do you not have to pay for it? There is no manufacturer producing AR for free. I know some countries have different government insurance plans and insurance is different from country to country but usage is still much higher in European countries where the patients pay than it is here.

The bigger difference has to do with the facilities that manufacture lenses. In Japan for example the majority probably 90% are manufactured by about 6 different lens manufactures. They don't have independent labs or in office labs like we do here and in each of these factories they invested in AR equipment and pushed the products as a complete package.

Here in the US in house quick delivery was determined to be more important than sending a lens surfaced at an in office facility out for AR.

Another factor was the first AR usage in the US was a failure due to the UV hard coating used almost exclusively in the US that was not very compatible with AR, so the AR got blamed as bad when it was the hard coating that the AR would not bond to.

[Pete Hanlin]

Someone (a rep) told me to think about music and how it has gone from records, to 8-tracks, to cassette tapes, then to CD's....still the same music, just a different delivery.
I'm glad our consultants were paying attention to my presentation at our recent National Sales Meeting! :)

The point was this: The content of the MUSIC is a lot more important than the format used to deliver it. When I hear practitioners say they only want to dispense "digitally surfaced designs" it just doesn't make any sense to me. Its like walking into a music store and saying "Hey, sell me some CDs!" without any regard for what's ON the CD! I'd rather listen to Billy Joel on a cassette tape than New Kids on the Block on a CD. I'd rather watch Star Wars on a VHS than Cabin Boy on DVD. Sure, DVDs and CDs make good music a bit clearer (though some would argue records actually sound better), but it doesn't matter what format you play it on, the New Kids will never match Billy Joel (IMHO)... Point is, traditionally surfaced PALs outperform digitally surfaced PALs when the design in the traditional lens is better (and there are independently conducted clinical studies which back this statement up).

To the original point... I agree that moving from 0.06 to 0.01D accuracy is "negligible" in terms of measurable benefit to the wearer. Just think about it- when does an examination end? When the patient can't tell a difference between lens 8 and 9 (or 9 and 10, etc...). Those lenses are usually 0.25D apart, and the wearer cannot tell a difference! How is that wearer supposed to notice a difference between a lenses that are 0.05D apart? Increased accuracy isn't a bad thing, of course- and perhaps we will be able to refract closer to the "ideal Rx," but in the end it comes down to a measurable benefit for the wearer. Digital surfacing- by itself- does not make a PAL "better." A good design makes a PAL better.

Which brings us to Varilux Physio Enhanced. We have some very encouraging clinical data which demonstrates a significant preference for Varilux Physio Enhanced (vs. Varilux Physio), so I'm pretty optimistic your patients will be impressed with the lenses (which is the end goal of us all).

[YrahG]

(and there are independently conducted clinical studies which back this statement up)......................................................... .........................................
Which brings us to Varilux Physio Enhanced. We have some very encouraging clinical data which demonstrates a significant preference for Varilux Physio Enhanced (vs. Varilux Physio), so I'm pretty optimistic your patients will be impressed with the lenses (which is the end goal of us all).

You mentioned independent clinical studies in the begining and in the end you are mentioning clinical studies again, are these Physio Enhanced studies independent as well?

[Pete Hanlin]

Are these Physio Enhanced studies independent as well?
Yes, they are. In the interest of full disclosure, I'll try to describe what I mean by independent (and leave it up to the reader to decide if the term is accurate).

When we conduct a clinical study, we contract with Schools of Optometry and/or other organizations which test ophthalmic products. Essilor funds the study, and reviews the study protocols- but the organization conducting the clinical procures the lenses and conducts the study.

When I say "reviews the protocols," I mean we ensure the testing is being conducted in a double-blind, randomized environment, with a population which is representative of the population as a whole (for most tests, sometimes we want to test a specific population- for example on polarization, we may want to specifically test pseudophakes). We have had outside organizations review our clinical testing protocols as well, which has resulted in further independent certification of the protocols.

"Double-blind" means neither the subject nor the examiner knows the identity of each product being tested (two pair of identical eyewear- the only difference is one has a small dot in the inside of the hinge... there is an assistant that knows which lens is which for recording purposes, but s/he does not interact with the subject). "Randomized" means the order in which the products is varied (further removing the possibility of the subject/examiner knowing which product is which, and also removing "order bias" from the subject).

Once the study is conducted, the organization provides an analysis of the results to Essilor. In the vast majority of cases, we grant permission for the organization to publish articles or posters on their findings- in many cases, I create "posters" which summarize the results. In other cases, the study may have been comparing developmental products (in which case, the results are sent back to Essilor R&D, which conducts even more tests than we do as part of the lens design process).

Conducting a clinical study is an expensive endeavor. For example, to remove as many variables as possible, we have to make sure all of the lenses a.) are made of the same material, and b.) have the same or similar AR treatment. The only material most competitors have in common is 1.67, so we usually end up ordering 80 pair of 1.67 w/AR PALs for the subjects. Usually you shoot for 40 or so subjects- knowing you need at least 30 subjects to acheive statistically significant findings (p-value of <0.05), and some subjects will "drop out" (for one reason or another, they will either not show for the visits or have a condition which excludes them from participation- such as an eye condition). Then the subjects have to be examined, fit with identical frames, and scheduled for the evaluations.

Anyway, when clinical tests are conducted between products in this environment, we are often able to acheive statistically significant results (i.e., one product is DEFINITELY favored over another- either globally or in certain aspects). Other times, we find there is very little difference in the performance of two products.

If I'm less than overwhelmed with some of the FBS digital products on the market, its because I've had them tested against traditional designs and have found that DESIGN has a much larger impact on product performance than the PROCESS used to make the lens. There are several FBS designs which do not perform as well as traditionally processed designs. Of course, I focus mostly on Varilux products- but I would suspect traditional Zeiss & Hoya lenses would also perform better than some of the "FBS designs" on the market today.

Main point to all this is as follows- the claimed "benefits" of FBS processing (keyhole effect, greater accuracy, and supposed reduction of peripheral distortion) do not appear to make an impact on the actual vision of real human subjects (which is what it all comes down to). For example, during a comparison of an FBS design to Varilux Comfort, a majority of subjects found Varilux Comfort to be wider in every zone compared to the FBS design (not to a level of statistical significance, but by a clear majority). I'm saying this- if you take a traditional design and move it to the back surface, you will not find a difference in the performance of the design in a clinically controlled environment. For all the hype about "full-back surface" benefits, they just don't pan out in real life (which is what I suspect practitioners will discover as they dispense more and more of these lenses).

Sorry for the length, but my involvement in the testing process over the past few years has really shed a lot of light on what makes a PAL "tick." I know digital surfacing sounds really cool- but its just another way to make a lens. That's not to say digital surfacing can't be used to create certain design elements which have significant impact (example, when Varilux 360 products are compared to non-360 products, we can measure improvements in performance with the 360 products), but digital surfacing alone just doesn't seem to make much difference in how a PAL performs.

[YrahG]

Are these Physio Enhanced studies independent as well?
Yes, they are. In the interest of full disclosure, I'll try to describe what I mean by independent (and leave it up to the reader to decide if the term is accurate).

When we conduct a clinical study, we contract with Schools of Optometry and/or other organizations which test ophthalmic products. Essilor funds the study, and reviews the study protocols- but the organization conducting the clinical procures the lenses and conducts the study.

When I say "reviews the protocols," I mean we ensure the testing is being conducted in a double-blind, randomized environment, with a population which is representative of the population as a whole (for most tests, sometimes we want to test a specific population- for example on polarization, we may want to specifically test pseudophakes). We have had outside organizations review our clinical testing protocols as well, which has resulted in further independent certification of the protocols.

"Double-blind" means neither the subject nor the examiner knows the identity of each product being tested (two pair of identical eyewear- the only difference is one has a small dot in the inside of the hinge... there is an assistant that knows which lens is which for recording purposes, but s/he does not interact with the subject). "Randomized" means the order in which the products is varied (further removing the possibility of the subject/examiner knowing which product is which, and also removing "order bias" from the subject).

Once the study is conducted, the organization provides an analysis of the results to Essilor. In the vast majority of cases, we grant permission for the organization to publish articles or posters on their findings- in many cases, I create "posters" which summarize the results. In other cases, the study may have been comparing developmental products (in which case, the results are sent back to Essilor R&D, which conducts even more tests than we do as part of the lens design process).

Conducting a clinical study is an expensive endeavor. For example, to remove as many variables as possible, we have to make sure all of the lenses a.) are made of the same material, and b.) have the same or similar AR treatment. The only material most competitors have in common is 1.67, so we usually end up ordering 80 pair of 1.67 w/AR PALs for the subjects. Usually you shoot for 40 or so subjects- knowing you need at least 30 subjects to acheive statistically significant findings (p-value of <0.05), and some subjects will "drop out" (for one reason or another, they will either not show for the visits or have a condition which excludes them from participation- such as an eye condition). Then the subjects have to be examined, fit with identical frames, and scheduled for the evaluations.

Anyway, when clinical tests are conducted between products in this environment, we are often able to acheive statistically significant results (i.e., one product is DEFINITELY favored over another- either globally or in certain aspects). Other times, we find there is very little difference in the performance of two products.

If I'm less than overwhelmed with some of the FBS digital products on the market, its because I've had them tested against traditional designs and have found that DESIGN has a much larger impact on product performance than the PROCESS used to make the lens. There are several FBS designs which do not perform as well as traditionally processed designs. Of course, I focus mostly on Varilux products- but I would suspect traditional Zeiss & Hoya lenses would also perform better than some of the "FBS designs" on the market today.

Main point to all this is as follows- the claimed "benefits" of FBS processing (keyhole effect, greater accuracy, and supposed reduction of peripheral distortion) do not appear to make an impact on the actual vision of real human subjects (which is what it all comes down to). For example, during a comparison of an FBS design to Varilux Comfort, a majority of subjects found Varilux Comfort to be wider in every zone compared to the FBS design (not to a level of statistical significance, but by a clear majority). I'm saying this- if you take a traditional design and move it to the back surface, you will not find a difference in the performance of the design in a clinically controlled environment. For all the hype about "full-back surface" benefits, they just don't pan out in real life (which is what I suspect practitioners will discover as they dispense more and more of these lenses).

Sorry for the length, but my involvement in the testing process over the past few years has really shed a lot of light on what makes a PAL "tick." I know digital surfacing sounds really cool- but its just another way to make a lens. That's not to say digital surfacing can't be used to create certain design elements which have significant impact (example, when Varilux 360 products are compared to non-360 products, we can measure improvements in performance with the 360 products), but digital surfacing alone just doesn't seem to make much difference in how a PAL performs.

Interesting points, thank you for sheding some light on your companies studies, I am a bit wiser today.

With the FBS I think you are both right and wrong here. I don't even necessarily think you are wrong more so than leaving key information out. FBS PALs as you point out are not in and of themselves better because they have been moved to the back surface. By having the design surfaced (notice I did not say back, front, or both) the software has the ability to design it on the fly rather than just make assumptions about many of the variables. The 3rd quarter I am hearing you will be releasing the Drx line of your companies designs, rather than unlock the potential of designing the PAL on the fly your company is going to surface the design on the back unchanged and is positioning it as a inferior product to the Enhanced. I am uspet that your company has taken a stance to position great technology as a parlor trick to bash the competition. I think until the Varilux line incorporates custom variable in the design of the lens (front, back, or both) it will always have a disadvantage to fully customized designs. I would like to see the Drx take advantage of the ability to customize the design.

Also on a side note the few studies of your companies that I have seen include pateints that were previous PAL wearers, since Varilux has the market share when it comes to PALs how do you ensure that the patient doesn't go from an older Varlux design to a newer improved version which would be a more natural adaption then lets say switching PALs from one manufacturer to another?

[Pete Hanlin]

YrahG,
Thanks for the thoughtful responses/objections.

By having the design surfaced (notice I did not say back, front, or both) the software has the ability to design it on the fly rather than just make assumptions about many of the variables.
Actually, this is a frequently misunderstood aspect of "FBS" digital surfacing. Most FBS lenses are not "designed on the fly" as you suggest. In most of the FBS lenses currently on the market, a design file is selected from which the lens is generated. Yes, the distance power is "added in" to the design file, but it is not "designed on the fly." Rather, there is a collection of pre-determined files from which a design is selected (which is really not that different from selecting a base curve and ADD in the form of a progressive blank). Zeiss Individual is an example of a FBS lens that is "designed on the fly" to a degree. Position of wear is taken into account, and you can measure the impact on design from lens to lens. This cannot be said of some of the other lenses on the market claiming position of wear customization.

Of course, the claim is asphericity/atoricity is used to "eliminate peripheral distortion." Unfortunately, a.) not all FBS lenses truly feature atoricity to reduce marginal astigmatism & power error, and b.) even if you do incorporate this rather easily calculated feature, its not going to impact "peripheral distortion" to a great degree (reducing marginal astigmatism isn't a bad thing, but it doesn't necessarily reduce distortion).

The 3rd quarter I am hearing you will be releasing the Drx line of your companies designs, rather than unlock the potential of designing the PAL on the fly your company is going to surface the design on the back unchanged and is positioning it as a inferior product to the Enhanced. I am uspet that your company has taken a stance to position great technology as a parlor trick to bash the competition.
Essilor's message on digital surfacing has remained rather constant- it adds nothing to the design on its own. As such, we do not plan to follow the path of some other manufacturers when it comes to making exaggerated claims on the performance of an FBS formatted product. The "parlor trick" is found in the claims of some FBS manufacturers who claim 20-30% (and more) gains in "width" when the design is moved the back. The "parlor trick" is leading practitioners and consumers to believe they will have "6x increased resolution" with digitally surfaced lenses (based solely on the theoretical 0.01D accuracy of DS vs. the 0.06D accuracy of traditional generating). The "parlor trick" is claiming that a lens is "designed on the fly" just because the surface is stored in a computer instead of on a mold.

Varilux offers several design features which are applied using digital surfacing. We have had 360 Optimized products on the market for some time, and we are launching Varilux Physio Enhanced next week which will feature customized wavefront correction. These products have been tested and we know they provide real benefits over the traditionally surfaced versions of the designs. Digital surfacing is a great thing- but (to the original point of this thread) the market has certainly gotten "carried away" with the supposed "benefits" of digital surfacing in and of itself.

Also on a side note the few studies of your companies that I have seen include pateints that were previous PAL wearers, since Varilux has the market share when it comes to PALs how do you ensure that the patient doesn't go from an older Varlux design to a newer improved version which would be a more natural adaption then lets say switching PALs from one manufacturer to another?
Excellent question- and a valid point. Which is why part of the initial subject interview process is to ascertain what design they are currently wearing. In many studies, we specifically ensure the subjects are not currently wearing either of the designs being tested. In some studies, there is a "washout" pair (which is a "control" design which is neither of the lenses being evaluated) which is worn for a period of time prior to the subject's visit.

Long story short, in my experience FBS lenses do not outperform traditionally generated designs on actual humans. I can understand why that upsets some people, but it just happens to be a statement of fact. If you want to believe DS lenses are "designed on the fly," feel free to believe that- but it doesn't appear to improve the performance of the lens on people- which I'm guessing is the main objective in the end.

[Now I See]

Pete~

I'll give you an example of a recent exchange I had with a patient...

The pt was wearing Comfort CR39 w/o ARC. I put him in a "digital" lens, CR39 w/ ARC (not a 360), pt had many complaints, so I switched him to a "better" design (still not a 360), pt had complaints, just not as many as the first time. Frustrated with the whole experience, I remade them again...back to his original comfort CR39 w/ ARC. He hasn't picked these up yet, but I wonder if, I would have had so much trouble if I had put him in the Comfort 360, since he was already "used to" the Comfort design??

[Pete Hanlin]

Hello Heather,
As with all troubleshoots, there are so many factors involved it is hard to say why a patient fails to adapt to a particular lens. Most PAL designs (traditional and digitally surfaced) are pretty good. That said, there are one or two FBS PAL designs in particular where I can imagine a Varilux Comfort wearer might notice a significant difference in various areas of performance! On the other hand, perhaps the FBS design was okay, but the processing wasn't quite right (its harder to verify conformity of each lens in a DS process vs. a traditional surfacing process, but that's another discussion). I'm not trying to toss either the design or the process "under the bus," I'm just saying there's a lot of potential causes. Then there's the patient him/herself! Who hasn't fit a patient with the same design, same Rx, same fitting parameters... only to hear "It just doesn't seem quite the same!"

Regarding Varliux Comfort 360, if the patient was already in Varilux Comfort, Varilux Comfort 360 should be an easy fit- because it is an optimized version of Varilux Comfort.

The 360 Optimization calculates an irregularly atoric back surface which is applied using digital surfacing. "Irregularly atoric" means it uses atoricity to match the distance Rx to the progression on a point-by-point basis. Hypothetically speaking- on a given lens the program knows that at point x=-3.1mm y=2.3mm from the PRP, the front progressive surface produces a power of +0.04 -0.18 x 002. Let's say the prescribed distance power is -1.25 -0.50 x 090. The calculation considers the power existing on the front and creates a curvature at the corresponding point on the back surface which will produce the prescribed distance power without altering the design of the progression (the design of a PAL is altered by distance power in traditional and FBS PALs).

Best regards,
Pete

[YrahG]

YrahG,
Thanks for the thoughtful responses/objections.

By having the design surfaced (notice I did not say back, front, or both) the software has the ability to design it on the fly rather than just make assumptions about many of the variables.
Actually, this is a frequently misunderstood aspect of "FBS" digital surfacing. Most FBS lenses are not "designed on the fly" as you suggest. In most of the FBS lenses currently on the market, a design file is selected from which the lens is generated. Yes, the distance power is "added in" to the design file, but it is not "designed on the fly." Rather, there is a collection of pre-determined files from which a design is selected (which is really not that different from selecting a base curve and ADD in the form of a progressive blank). Zeiss Individual is an example of a FBS lens that is "designed on the fly" to a degree. Position of wear is taken into account, and you can measure the impact on design from lens to lens. This cannot be said of some of the other lenses on the market claiming position of wear customization.

Of course, the claim is asphericity/atoricity is used to "eliminate peripheral distortion." Unfortunately, a.) not all FBS lenses truly feature atoricity to reduce marginal astigmatism & power error, and b.) even if you do incorporate this rather easily calculated feature, its not going to impact "peripheral distortion" to a great degree (reducing marginal astigmatism isn't a bad thing, but it doesn't necessarily reduce distortion).

The 3rd quarter I am hearing you will be releasing the Drx line of your companies designs, rather than unlock the potential of designing the PAL on the fly your company is going to surface the design on the back unchanged and is positioning it as a inferior product to the Enhanced. I am uspet that your company has taken a stance to position great technology as a parlor trick to bash the competition.
Essilor's message on digital surfacing has remained rather constant- it adds nothing to the design on its own. As such, we do not plan to follow the path of some other manufacturers when it comes to making exaggerated claims on the performance of an FBS formatted product. The "parlor trick" is found in the claims of some FBS manufacturers who claim 20-30% (and more) gains in "width" when the design is moved the back. The "parlor trick" is leading practitioners and consumers to believe they will have "6x increased resolution" with digitally surfaced lenses (based solely on the theoretical 0.01D accuracy of DS vs. the 0.06D accuracy of traditional generating). The "parlor trick" is claiming that a lens is "designed on the fly" just because the surface is stored in a computer instead of on a mold.

Varilux offers several design features which are applied using digital surfacing. We have had 360 Optimized products on the market for some time, and we are launching Varilux Physio Enhanced next week which will feature customized wavefront correction. These products have been tested and we know they provide real benefits over the traditionally surfaced versions of the designs. Digital surfacing is a great thing- but (to the original point of this thread) the market has certainly gotten "carried away" with the supposed "benefits" of digital surfacing in and of itself.

Also on a side note the few studies of your companies that I have seen include pateints that were previous PAL wearers, since Varilux has the market share when it comes to PALs how do you ensure that the patient doesn't go from an older Varlux design to a newer improved version which would be a more natural adaption then lets say switching PALs from one manufacturer to another?
Excellent question- and a valid point. Which is why part of the initial subject interview process is to ascertain what design they are currently wearing. In many studies, we specifically ensure the subjects are not currently wearing either of the designs being tested. In some studies, there is a "washout" pair (which is a "control" design which is neither of the lenses being evaluated) which is worn for a period of time prior to the subject's visit.

Long story short, in my experience FBS lenses do not outperform traditionally generated designs on actual humans. I can understand why that upsets some people, but it just happens to be a statement of fact. If you want to believe DS lenses are "designed on the fly," feel free to believe that- but it doesn't appear to improve the performance of the lens on people- which I'm guessing is the main objective in the end.

I hope this doesn't come off as rude since I enjoy your posts but your post seemed quite canned. I did not suggest that most FBS lenses are designed "on the fly", in contrast I said:

By having the design surfaced (notice I did not say back, front, or both) the software has the ability to design it on the fly rather than just make assumptions about many of the variables.

So the entire first two paragraphs are great information but don't address the question of why Essilor's newest offerings this year choose not to take advantage of the newest technology?

You mentioned "custom wavefront correction", The design is on the front and incorporates nothing more than the prescription, seg hgt, and PD supplied so custom wouldn't be my first choice in descriptive terms. Second you mention wavefront, yet I have not seen any way to incorporate wavefront aberrometry into your lens design so that term again is a bit misleading.

The information I have recieved seems to put a lot of emphasis on pupil size, stop size, or aperature depending on who you ask. This leads me to believe that the correction emphasis is on spherical aberration. When you mentioned above in your post:

1. power error
2. marginal astigmatism
3. distortion
4. spherical aberration
5. coma

Of the seidel aberrations I would rank them in the order above as to their importance. The pupil size is small enough that spherical aberration and coma are negligable similar to your example on the benefits from the potential accuracy gain from 0.o6D rounding to 0.01D rounding (again notice I said potential).

Your above posts seems to provide just as much claims as you seems to believe your competitors claim. Also the 30% wider field claim I heard was in reference to the physio enhanced, physio 360, and many of the other Varilux products when they were first introduced. To this day I don't have a base line measure of what "30% wider than" really means. Are we talking about 30% wider than a peanut or a golf ball? I have heard it is a reference to the first generation PAL designs in which case many manufacturers can make similar claims.

[Pete Hanlin]

I hope this doesn't come off as rude since I enjoy your posts but your post seemed quite canned.
I don't think you're being rude at all.

I did not suggest that most FBS lenses are designed "on the fly?"
Okay, so which lenses do you feel are "designed on the fly" (because there are not many)? I can think of a few examples: Varilux Ipseo IV, Varilux 360 products, Varilux Physio Enhanced, Zeiss Individual. Most of the other products on the market are calculated using the process I described earlier (i.e., there is a catalog of pre-determined designs, and the computer selects the best file).

So the entire first two paragraphs are great information but don't address the question of why Essilor's newest offerings this year choose not to take advantage of the newest technology?
I'm afraid I do not follow your question. The newest offering this year is Varilux Physio Enhanced, which is digitally surfaced on the back- with a molded front surface. I'm just not sure what "newest technology" isn't being taken advantage of...

Your above posts seems to provide just as much claims as you seems to believe your competitors claim. Also the 30% wider field claim I heard was in reference to the physio enhanced, physio 360, and many of the other Varilux products when they were first introduced.
Obviously, I disagree. Competitors are claiming to provide a 30% gain in width due to the geometrical advantage of having the design on the back surface (and simple geometry demonstrates the actual advantage is around 6%). The 30% claim on Varilux Physio is related to the design (specific comparison is to Varilux Panamic) and has been demonstrated on actual wearers. Specifically, the vertical alignment of cylinder in the near intermediate periphery provides a greater width of binocularity- which results in the perception of a wider intermediate field of view.

Regarding your skepticism re: wavefront correction, all I can say is the lenses have been measured for MTF (modulation transfer function), which is objectively higher than competitive lenses. Additionally, we have studies which show the preference for Varilux Physio Enhanced increases in lower light conditions (which is exactly what one would expect if higher order aberrations are being controlled) compared to Varilux Physio. Finally, we are measuring contrast perception on actual humans wearing the lenses.

I completely agree with a skeptical attitude towards new products (especially given the "fuzzy" nature of most ophthalmic marketing). On the other hand, considering one of my main duties at Essilor is product testing, you should be able to understand that I get a little frustrated at some of the unsubstantiated (and sometimes demonstrably erroneous) claims out there when we spend so much time, effort, and resources towards proving the performance of our products. I can demonstrate the benefits of our products on real wearers- I do not believe the claims of most digitally surfaced lenses can be substantiated in the same way.

Best regards,
Pete

[YrahG]

I did not suggest that most FBS lenses are designed "on the fly?"
Okay, so which lenses do you feel are "designed on the fly" (because there are not many)? I can think of a few examples: Varilux Ipseo IV, Varilux 360 products, Varilux Physio Enhanced, Zeiss Individual. Most of the other products on the market are calculated using the process I described earlier (i.e., there is a catalog of pre-determined designs, and the computer selects the best file).

If you can honestly say that the Physio products are designed on the fly, both the 360 and the enhanced then our dialog is done there is no where else to go. Good luck with your product launch.

[Pete Hanlin]

Okay, well then- it was nice talking with you!

For the record, both Varilux 360 products and Varilux Physio Enhanced are, in fact, "designed on the fly" (to use your expression). In fact, the calculations for these lenses are done remotely (the laboratory uses a high speed connection to download the tool path for each lens- the calculation cannot be done on a desk top computer). This set-up is not unique to Essilor (my understanding is Zeiss Individual requires a remote connection as well). There are no pre-set files for the back surface design- each lens surface is individually calculated.

BTW, I notice you didn't answer my question (i.e., what lenses do you think are "designed on the fly").

For anyone else that has been following this thread... Just because a lens is digitally surfaced from a blank having a progressive front surface doesn't mean it can't be "designed on the fly." I think we all agree a single spherical blank can be used to make all sorts of different progressive designs (this is the premise behind the FBS format). The design elements you place on the back surface change the lens into any number of different designs.

Well, you can do the same thing with a blank having a progression on the front surface. Depending upon the design you place on the back, you can shorten the progression, change the zones, or change the entire progression. In fact, theoretically you could place a design on the back surface which changes the lens back into a single vision lens if you made the right calculations.

One of the great myths of digital surfacing is that somehow having a spherical front surface is the best format for a progressive lens. This is untrue for a number of reasons. For example, in a traditional format (progression on the front), ADD power is created by increasing the base curve. A traditional progressive lens with +3.00 ADD will increase in curvature by approximately 3 diopters on the front surface. Conversely, a progression with +3.00 ADD placed on the back surface will have a back surface that decreases in curvature by approximately 3 diopters. Professor Mo Jalie has an interesting paper which discusses this subject towards the end at the following link: http://www.ukoptometry.co.uk/wp-cont...-07revised.pdf

Again, digital surfacing is a cool technology which opens great new possibilities in progressive design. The best selling digitally surfaced PALs in the world are made by Essilor (over two million pairs of DEFINITY lenses have already been sold in the US alone), so I have nothing against the technology. I'm just hoping in 2010 we can start looking at this technology realistically (I'm a little tired of reading articles devoted to "How to sell digitally surfaced lenses").

Above all, we need to stay focused on how all these PALs are being FIT. Getting the fit wrong by 1mm or so is going to impact the performance of the design a heck of a lot more than whether the lens is digitally surfaced or not.