Digitally Surfaced PALs (Free Form) Clarified

[AWTECH]

ZEISS and SOLA utilize full optical optimization for their free-form lenses. This process provides a truly unique lens design that has been designed in real time for each wearer in order to minimize the aberrations produced in the as-worn position by the wearer's specific prescription.

Some (but not necessarily all) other free-form lens suppliers provide only "dumb" free-form lenses, which simply represent the sum of a traditional progressive lens design and a traditional prescription surface. In other words, the wearer's prescription curves are simply added mathematically to a fixed progressive lens design, which is then either placed on the back surface or perhaps split between the front and back surfaces. This process essentially replicates the performance of a semi-finished progressive lens design, offering only minimal benefit to the wearer -- aside from the small reduction in skew distortion and slightly wider fields of view that you might attain by moving the progressive optics completely (or even partially) to the back surface.

I won't get into finger-pointing or further speculation here though. A review of the relevant patents from each company will provide some indication of their capabilities as well as the potential sophistication of their free-form lenses.

I concure with the statement by Darryl. Many people in this industry are not aware of the products my company, ICE-TECH Advanced Lens Technology produces but our progressives are not in the Dumb catagory. Each is individually designed.

[Digitaleye]

excluding Ziess & Rodenstock, most of these "free form" and "Digitally Surfaced" products can be explained as "SAME S&!T DIFFERENT SIDE"

the marketing opportunity's combined with reduction in processing costs, after capital costs are recovered for equipment, are HUGE.
the sad part is these manufacturers are sucking us in with mostly standard designs and little advantage to the end user, OUR PATIENTS !!!! (unless you feel a 1.5mm reduction in vertex distance is an advantage)

Regarding your above statements:

1. Same S**T different side - aside from the power accuracy differential.. and yes the opposite side of the lens.. These designs from Seiko (there will be additional designs introduced in the US shortly) Shamir (on the verge of releasing a number of exiting design upgrades) and Indo (having produces FF lenses in their home European markets for years) are anything but the same.. as the progressive surface is modified per Rx in ways that simply ARE not possible in conventional cast PAL's. The marketing oppertunity for the dispenser is huge as is the new ability to offer a stand out from the pack PAL fit.

2. The idea that this is hugely profitable after machine costs are recovered. - When one becomes familiar with the true costs of creating the correct envirement to fabricate these complex surfaces .. staffing the facility correctly..paying the liscencing and royalty fees.. and oh yeah the machines themselves..reality sets in... However, squirting a 10 year old design PAL into a mold for 50 cents..selling it to a lab for 35 dollars and to the ECP for 60..THATS A GOOD BUSINESS!!..LOL

[bhess25]

You indicate that the fact that many of the very expensive, I assume you would include the ICE-TECH lenses in this do not use front side aspheric designs using direct to surface. An aspheric design, means non-spherical it does not mean a lens is going to be thinner. Our technology uses a spherical front and a non-spherical backsurface individualized design. Our design technology allows us to produce much thinner lenses using a spherical front surface than can be had by the companies you mentioned using their front side molded PAL designs.

B.S. but good try on selling that technology of yours...aspheric lenses are in fact thinner...i have surfaced a poly blank at +4.25 with a center of 5mm and then an aspheric poly blank at +4.25 with a center of 3mm...all using the innovations program...ive also done a -9.00 in poly with the edge thickness being ungodly monsterous...and then in aspheric that ended up about 20% thinner at the edges....im not realy buying this whole digital load of crap anyway...its the same damn lens that was developed 10 years ago and to sell more we call it "digitaly surfaced" when for half the price they can still get a quality lens that still has the potential to outpreform the digital crap...it all comes down to taking more money from people...hey i have a great idea....lets all come up with some new B.S. to throw at people and call ourselves "essilor"!!!...Ill stick to the image!!

[AWTECH]

B.S. but good try on selling that technology of yours...aspheric lenses are in fact thinner...i have surfaced a poly blank at +4.25 with a center of 5mm and then an aspheric poly blank at +4.25 with a center of 3mm...all using the innovations program...ive also done a -9.00 in poly with the edge thickness being ungodly monsterous...and then in aspheric that ended up about 20% thinner at the edges....im not realy buying this whole digital load of crap anyway...its the same damn lens that was developed 10 years ago and to sell more we call it "digitaly surfaced" when for half the price they can still get a quality lens that still has the potential to outpreform the digital crap...it all comes down to taking more money from people...hey i have a great idea....lets all come up with some new B.S. to throw at people and call ourselves "essilor"!!!...Ill stick to the image!!

You don't understand the technology I am talking about. I don't think that your BS comments are appropriate to a technology that you are not understanding. (You are not alone)

In your example one is using a front spherical curve and a cut back spherical curve. The other is using a front aspheric curve and a back spherical curve. In our design the front is spherical and the back is aspherical. In single vision the advantages are not as great as in a PAL. For example I can produce a poly plus lens that is about 50% thinner than if a molded blank is used.

[Digitaleye]

You don't understand the technology I am talking about. I don't think that your BS comments are appropriate to a technology that you are not understanding. (You are not alone)

In your example one is using a front spherical curve and a cut back spherical curve. The other is using a front aspheric curve and a back spherical curve. In our design the front is spherical and the back is aspherical. In single vision the advantages are not as great as in a PAL. For example I can produce a poly plus lens that is about 50% thinner than if a molded blank is used.

Thank you for the very concise and correct explanation. Interesting that one would feel so threatened and compelled to throw out that which is clearly not understood. Do people not come here for clarification? If the question here is spherical vs. aspheric, then why is the introduction of aspheric controlled curves on the back of a surfaced lens a far reaching concept?

[AWTECH]

Digital Eye:

Thank you for the verification of my post. I seem to hear all of the challenges to the type of digital surfacing technology that we use from people who have no actual experience with this technology.

I doubt that you can talk to any of our customers who have used 10 job that will have any doubts.

[bhess25]

i was just causing trouble....A.D.D. and boredom dont mix!!!

[Robert Martellaro]

Some (but not all) other free-form lens suppliers provide only "dumb" free-form lenses, which simply represent the sum of a traditional progressive lens design and a traditional prescription surface.

I sure would like to get my hands on that information. If you're ever in Milwaukee I'll feed you a half-dozen boilermakers to spill your guts. I promise not to divulge any information that I'm able to remember the next morning.

A review of the relevant patents from each company will provide some indication of their capabilities as well as the potential sophistication of their free-form lenses.

I'm not having much luck with patent searches but I'll keep at it. I did run across this article- part two should be interesting.

http://www.opticianonline.net/assets...px?ItemID=2735

[Darryl Meister]

Robert, I'm publishing a two-part article on progressive lenses in a coming issue of Clinical and Experimental Optometry, which will include a comprehensive review of the optics of "free-form" and "wavefront" progressive lenses. Although I wrote it for a fairly technical audience, you should also be able to track down a great deal of relevant information from the bibliography.

[Robert Martellaro]

Thanks Darryl, I'll watch for it. You're right, I won't be able to follow the math, (who really understands differential geometry anyway?), so I'll read between the lines and search the bibliography.

For those who are interested, I did get quite a few hits on progressive power lenses at Patent Storm.

http://www.patentstorm.us/patents/se...ageField2.y=11

One patent, by Rodenstock, addresses some of the concerns I had earlier in this thread concerning high plus along with high ADD RXs made with backside free-form PALs.

http://www.patentstorm.us/patents/72...scription.html

[mahmoud.hamza]

can some one tell me what is the difference between a free form progressive lense and normal progressive lens in optical and vision qualities

[mahmoud.hamza]

dear friends
Hello!!
our company planifye to introduce free form technologie .
can you please send me some information about this technologie and the differece between freeform progressive lenses and normal progressive lenses
thanks for all :-)

[HarryChiling]

Let me air this one gripe I have about FF lenses. So far the information given has been nothing but marketign hype with not much in the form of technical data presented to the ECP, so the ECP's mind is left to wander and the marketing drones do such a great job of making all lens desings sound rosie unless someone puts out a good instructional or education piece describing the various benefits and HOW they are acomplished then in general ECP's are going to be slow to adopt. I have seen this tredn since they ahve come out, people loved them and talked about them like they were the future and now they are questioning certain aspects of what they are told, because there is no knowledge or data to back up any of the claims.

Now I understand fully the benefits of FF lenses. Forgive me if I don't talk like a cowboy, but this is not the bull that bucks me. I get a headache just trying to memorize the jargon that every company is using for their flavor lens design, but I know what is possible and what it can do. I have sat in front of equipment and watched it work and seen teh level of accuracy and the low level of inaccuracy. (amazing to see the equipmet monitor minute changes in position down to fractios of fraction of a diopter). Here is where the kink in the chain is formed and it won't suprise anyone that this is my opinion. Since the '60s the average refraction has gone from an accuracy of 0.12 to 0.25 or doubled, I have seen in the last ANSI standard the inacuracy of progressives slip, the axis for low power astgmats has doubled. These standards insinuate that a significant margin of error is acceptable in prescription eyewear. Progressives now given the most leeway due to molded front surfaces not being as close to the intended desing as hoped for.

With all this data available to me readily, why would I believe that now we need to go backwards again to more accurate? The latest standards released were released during a time when FF technology was being used. What changed that drastically oevr the course of a few years that all of a sudden the patient needs this higher level of accuracy and why was it acceptable for such a large margin of error before and now we need to believe that we need to be more accuarte?

Now before we get into third and fifth order theory, why would I put more merit in third and fifth order aberations when the tolerance on 1st order aberrations are IMO garbage, yet patients accept it and our industry as a whole has embraced it?

I think the current molded lenses do a great job for a majority of patients seen through an average ECP's office and before I hear arguement, that is one of the driving reasons for loosening standards that the number of people that will notcie the difference would be small and acceptable. I would like to see a more accurate Rx if anything before I would be anywhere interested in the accuracy of the final product. Untill this is done these lenses are just prettier crap, but crap none the less.

I would also suggest that if the investment is to be made in designs why not scrap the FF and the manufacturers invest more in the number of base curves available in SF stock this too would help to lower the amount of third order aberations that are present in todays Rx's with exception to a few, but that's not profitable to manufacturers. My lab cannot produce FF lenses in house, so for me it would be like going from paying wholesale for a product to paying retail. Give me a good desing with plenty of options and a good range in BC's and I will work my wonders within acceptable tolerance by the same manufacturers that are provideing the FF products.

Allen your product is not amazing for the level of accuracie IMO it's amazing for the level of craft. I have seen your stuff and some of it is on the razor edge of function and form. This is the appeal towards your lenses IMO.

Darryl I know your company prides itself on accuracy and patient satisfaction, yet I think the enviornment for this technology isn't there. Heck we still have auto mechanics becoming opticians overnight in our country this technology makes it easier for them to mimic my ability to more accurately fit a lens with little knowledge and thought involved, but the cost is our businesses profits for this level of easy.

[AWTECH]

Harry Said:

Allen your product is not amazing for the level of accuracie IMO it's amazing for the level of craft. I have seen your stuff and some of it is on the razor edge of function and form. This is the appeal towards your lenses IMO.

I think you are missing one of the main benefits to the type of technology we use at ICE-TECH. The far vision is much better from side to side and the intermediate channel is about 30% wider. You can not get the same benefit for the patient in a traditional front molded lens that you can with a great individualized design. This technology does provide better vision in almost all cases. (Our wrap lens technology is in another catagory altogether)

You are correct that better refraction will also help.

[HarryChiling]

The far vision is much better from side to side and the intermediate channel is about 30% wider. You can not get the same benefit for the patient in a traditional front molded lens that you can with a great individualized design.

Don't do that, of course it's liek compareing apples to orangs the benefits are definately there, but the average ECP will recieve a job from a lab using this technology and will wonder how to verify it's accuracy and the lab tells them that they should be checking the as worn or compensated Rx, but then the lab will also say this computation is proprietary to their business. And now I smell trouble, suddenly the lab has a zero breakage because they don't have to tell you how they computed the Rx so the comped Rx could be anything, like whatever ends up coming off the conformable laps. Plus they could alway fall back to saying well we are allowed a margin of error of XXX according to ANSI, so there is no way to hold a lab to any kind of quality standard because there is no transparency in the process. Heck just recently someone posted a thread abotu a lab trying to convince them that they were using the lensometer wrong when measuring a traditionally surfaced lens instead of ownign up to a mistake.

So to me I won't buy accuracy that I hav eno way of verifying it's just not kosher.

[AWTECH]

Don't do that, of course it's liek compareing apples to orangs the benefits are definately there, but the average ECP will recieve a job from a lab using this technology and will wonder how to verify it's accuracy and the lab tells them that they should be checking the as worn or compensated Rx, but then the lab will also say this computation is proprietary to their business. And now I smell trouble, suddenly the lab has a zero breakage because they don't have to tell you how they computed the Rx so the comped Rx could be anything, like whatever ends up coming off the conformable laps. Plus they could alway fall back to saying well we are allowed a margin of error of XXX according to ANSI, so there is no way to hold a lab to any kind of quality standard because there is no transparency in the process. Heck just recently someone posted a thread abotu a lab trying to convince them that they were using the lensometer wrong when measuring a traditionally surfaced lens instead of ownign up to a mistake.

So to me I won't buy accuracy that I hav eno way of verifying it's just not kosher.

What about an individualized lens that is not a wrap and the verification is done in the same way as a molded lens? As I said our wrap technology is in a different catagory than a dress wear individualized lens.

As for wrap frames with compensated Rx's and verification, I think this gets back to legacy issues. Opticians trust their lensometers without monthly verifications from lensometer verification companies, why can't an optician adapt to a new way of verification? If the compensation is represented as correct and the optician checks the compensated powers, why can this not become an acceptable way of verification?

Since the individualized lenses are so new and wrap technology with compensated Rx is just coming into limited use, shouldn't the despensing optician provide a better product for their patient who want such a product? Or should the patient be forced to use non-compensated Rx's since the optician can not verify the compensated Rx.

I think ultimately the patient and better vision is the goal.

[HarryChiling]

[quote=AWTECH;211409]If the compensation is represented as correct and the optician checks the compensated powers, why can this not become an acceptable way of verification?
[quote]

I think your missing the point, how do I know that the compensation being represented is correct? If the company provides no way of verifying that the compensation is correct than I have to go on the companies word. What if the Rx came out wrong at the lab and the lab just used whatever Rx actually came off the polishers as the compensated Rx, breakage would go down so the company would make money and with the accuracy of the equipment it might even be close enough to pass ANSI? I am not paying for accuracy that I can not verify, and I am not trying to pass it off to a patient as accurate when I cannot be sure.

[AWTECH]

[quote=HarryChiling;211470][quote=AWTECH;211409]If the compensation is represented as correct and the optician checks the compensated powers, why can this not become an acceptable way of verification?

I think your missing the point, how do I know that the compensation being represented is correct? If the company provides no way of verifying that the compensation is correct than I have to go on the companies word. What if the Rx came out wrong at the lab and the lab just used whatever Rx actually came off the polishers as the compensated Rx, breakage would go down so the company would make money and with the accuracy of the equipment it might even be close enough to pass ANSI? I am not paying for accuracy that I can not verify, and I am not trying to pass it off to a patient as accurate when I cannot be sure.

Harry: My point was that if you know your supplier and have used their compensated lenses the following will be true:

1- You will have some degree of known patient satisfaction
2- You will be offering the patient a better lens solution than non-compensated

In addition as an optician you currently make many assumptions of correctness. Refraction, Lensometer used to verify, etc.

As a dispensing optician the checks that have been historically used were developed to eleminate potential errors, many of these errors are for self checks. That is the the engraving marks on a progressive help you verify not only the labs work but also the optician as you are able to check if you measured the fitting height correctly, or if another optician did.

The way compensations are currently used there are many chances for errors with double entry, incorrect frame angle measurements etc. Fortunately at ICE-TECH we have the knowledge, tools and skill to make correct measurements. Our software is single data entry so the compensation can not be incorrectly entered, only the original Rx. We combine this compensation with an individualized design to work with the frame and patient prescription giving the patient a much better quality lens than a non-compensated wrap that an optican can confirm is to the original RX.

Just curious, since you use your own compensator you developed, do you have the patients take your compensated lenses to another optician before you advise them to wear them. I think you maybe looking at this issue from your own perspective and concluding what others do is not correct but when you do the same it is correct. I am not trying to throw stones at you just asking you to look at where the optical world is in terms of compensation today and where you are with this issue. Personnally I know you understand the compensation issue and I would not have a problem at all with sending a friend of mine to have you make a pair of compensated wrap sunglasses.

Opticians need to have confidence in who they order any lens from and know that they are knowledgeable and capable of producing a lens that will provide the best vision for their patient within the budget the lenses were sold to the patient.

[HarryChiling]

Just curious, since you use your own compensator you developed, do you have the patients take your compensated lenses to another optician before you advise them to wear them. I think you maybe looking at this issue from your own perspective and concluding what others do is not correct but when you do the same it is correct. I am not trying to throw stones at you just asking you to look at where the optical world is in terms of compensation today and where you are with this issue. Personnally I know you understand the compensation issue and I would not have a problem at all with sending a friend of mine to have you make a pair of compensated wrap sunglasses.

Allen I am glad you brought that up. That is why I use my own, I know where the compensation came from, I know how it works, I knwo that if it spits out a number and then I don't surface it correctly according to that number that I am not just going to go back and change the numbers to match what I have surfaced. I am in total control of the process, it's transparent to me, now if they went to another optician he wouldn't be able to confirm that the Rx was done correctly.

I have mentioned in the past offering a small business card size CD with an Rx decompensator on it for the patient or office then applying a laser etching like progressives or even airbrushing a F=? P=? and this would contain the F= Faceform tilt used to compensate and the P= Pantascopic tilt so that a provider can then run it through the decompensator and know for sure that the software jives with the Rx. That would make the changes transparent.

Their was a time back in the day when OD's threw a fit if the Rx was compensated for vertex. Tilt and Wrap or even as worn should have transparency to the process otherwise it doesn't work for me, and yes from my standpoint it doesn't work, but it is also considering that I will have more happy patients when they don't here things like these don't match the Rx our doctor provided take it back to the optical you got it.

[AWTECH]

Harry: My point is that with your knowledge of compenstion you can look at verification of the multiple calculations involved. Many opticians do not have your understanding of this, and to have the angle and tilt engraved would be possible. I think that as this compensation issue becomes better utilized, the optician can trust a source such as ICE-TECH to properly manage this for them. In a small office with surfacing and doing the calculations on site, such as you do, it is possible to control this within your own walls.

Rather than make a set of standards to check for wrap angle and tilt, which will be confusing to many dispensing opticals, I think it is better for the optical retailers to trust their source. With so many unlicensed and the lack of knowledge at the retail level in general, making a more complex verification standard may create more questions for many than answers.

The OD issue is an education point that needs to be addressed. That is why I suggest the retailer use a trusted source for this type of lens and let the OD that has question get the answers from the source. We explain this process to many OD owners and most understand or say they do, then turn us over to the person running the Optical department.

I understand from your point of knowledge why you see it the way you do, but the real world of retailing eyewear is not ready for this complex verification.

Optical retail owners would see this as an increase in expenses with little financial gain. You would need more knowledgeable opticians verifiying these wrap lenses using your method.

[HarryChiling]

Optical retail owners would see this as an increase in expenses with little financial gain. You would need more knowledgeable opticians verifiying these wrap lenses using your method.

So the cost to verify the Rx isn't justifiable, but the higher cost of these lenses is? Again it boills down to accuracy with these lenses.

Comfort boost a 95% acceptance and many other progressive suppliers boast just as high numbers and I have seen offices go from 80% adaption and lower to 95% and better just by learning how to measure lenses. Their are more cost effective ways to provide the patient with accuracy. I see the benefit to FF, it covers the 5% or less that I can't fit.

[AWTECH]

So the cost to verify the Rx isn't justifiable, but the higher cost of these lenses is? Again it boills down to accuracy with these lenses.

Comfort boost a 95% acceptance and many other progressive suppliers boast just as high numbers and I have seen offices go from 80% adaption and lower to 95% and better just by learning how to measure lenses. Their are more cost effective ways to provide the patient with accuracy. I see the benefit to FF, it covers the 5% or less that I can't fit.

Harry: I think you missed my points.

Regarding costs: This is not a cost issue, I doubt that our single vision lenses cost any more than a traditionally surfaced lens with comperable treatments. Comparing apples to apples we are competitive, not the cheapest but also not the most expensive either.

I agree the knowledge you have and the way you run your operation you may only benefit by 5% usage of freeform at this time. Very few other retailers are in your situation. How many have surfacing and your knowledge in a one store operation, with the flexiblity to offer the type of products you can offer?

I am not looking at this from how you need run your specific operation. I am looking at how the general independant optical retailers can offer wrap around individualized lenses with confidence, and give their patients a great product. Not just any lab can offer the type of product ICE-TECH can offer, and not just any optician can replace you and offer your customers what you are offering.

I don't know why you are so resisting this new technology of digital surfacing, other than you don't have it in your location. In previous threads you have talked about how good it is and you have even written articles about how it takes lens manufacturing to a new level. Like any new technology it is not for everyone for all uses. It will take time to gain a greater percentage of the market, but if optical retailers don't offer these product to their customers, as the customers hear about the benefits, some of these customers will become customers of a competitor.

[HarryChiling]

Harry: I think you missed my points.

Regarding costs: This is not a cost issue, I doubt that our single vision lenses cost any more than a traditionally surfaced lens with comperable treatments. Comparing apples to apples we are competitive, not the cheapest but also not the most expensive either.

I agree the knowledge you have and the way you run your operation you may only benefit by 5% usage of freeform at this time. Very few other retailers are in your situation. How many have surfacing and your knowledge in a one store operation, with the flexiblity to offer the type of products you can offer?

I am not looking at this from how you need run your specific operation. I am looking at how the general independant optical retailers can offer wrap around individualized lenses with confidence, and give their patients a great product. Not just any lab can offer the type of product ICE-TECH can offer, and not just any optician can replace you and offer your customers what you are offering.

I don't know why you are so resisting this new technology of digital surfacing, other than you don't have it in your location. In previous threads you have talked about how good it is and you have even written articles about how it takes lens manufacturing to a new level. Like any new technology it is not for everyone for all uses. It will take time to gain a greater percentage of the market, but if optical retailers don't offer these product to their customers, as the customers hear about the benefits, some of these customers will become customers of a competitor.

It is great technology, but the manufacturer has to provide something better than just a product. Your right that the level of accuracy is there and your right that the lenses do have great benefits. But lokk at all of this from my point of view:

Some (but not all) other free-form lens suppliers provide only "dumb" free-form lenses, which simply represent the sum of a traditional progressive lens design and a traditional prescription surface. In other words, the wearer's prescription curves are simply added mathematically to a fixed progressive lens design, which is then either placed on the back surface or perhaps split between the front and back surfaces. This process essentially replicates the performance of a semi-finished progressive lens design, offering only minimal benefit to the wearer -- aside from the small reduction in skew distortion and slightly wider fields of view that you might attain by moving the progressive optics completely (or even partially) to the back surface.

I won't get into finger-pointing or further speculation here though. A review of the relevant patents from each company will provide some indication of their capabilities as well as the potential sophistication of their free-form lenses.

Oh so their not all built alike, so which ones address what issues?

I concure with the statement by Darryl. Many people in this industry are not aware of the products my company, ICE-TECH Advanced Lens Technology produces but our progressives are not in the Dumb catagory. Each is individually designed.

Ok, so hoooooowwwwwwww?

Same S**T different side - aside from the power accuracy differential.. and yes the opposite side of the lens.. These designs from Seiko (there will be additional designs introduced in the US shortly) Shamir (on the verge of releasing a number of exiting design upgrades) and Indo (having produces FF lenses in their home European markets for years) are anything but the same.. as the progressive surface is modified per Rx in ways that simply ARE not possible in conventional cast PAL's. The marketing oppertunity for the dispenser is huge as is the new ability to offer a stand out from the pack PAL fit.

Upgrade to design, what was wrong with the old ones? New designs what was wrong with the old one?

In our design the front is spherical and the back is aspherical. In single vision the advantages are not as great as in a PAL. For example I can produce a poly plus lens that is about 50% thinner than if a molded blank is used.

Wether the aspheric is on the fron or back does not make much of a difference. On a plus lens an aspheric front flatten as it reaches the periphery on a plus lens with the aspheric back the lens steepens the curve as it goes to the periphery, it will alow a slightly thinner lens, but opticaly their is not that great of a benefit.

What data can you provide on your desing over lets say a Comfort, Natural, Ovation, AO Compact, Navigator? That's what I need to know. If we are bringing things up it was also you that refused to map out progressive lens designs in hopes of shedding light on some of the differences in progressive lens designs. Instead I have to sedn lenses to India, because manufacturers in the US have something to hide. Transparency is important to me. I don't trust my mother, so to ask me to trust a manufacturer is a huge reach. I have used a few of the FF lenses and they are different, but not better. I have no way of saying better, I understand the capability of the equipment and the things I wrote were on the capability of the equipment, the lenses in your case I have seen and did truly enjoy. I apoligize if you got the impression that I thought they were more accurate just by lookign at them and holding them in my hand. I enjoyed the form, I can verify that the form can be pushed to some incredible limits, but even their the polishers still introduce some limitations on form. I have yet to see functionality of these lenses. I have seen maps of a ton of siffernt desings I have yet to see one of the FF's this way and I believe this is how they are verified on your end so it's not a stretch to see these lenses in comparison to others FF and traditional. I refer to what gets handed down as lolipops, telling me they are more accurate and have wider fields of view are nothin but sweet little treats to keep me suckling from the teet. Provide me some meat, provide the average optician some meat other wise why switch from using a design with 95% adaption to a lens that has lets say 99% adaption at double my cost. If I double my bills to satisfy 4% more people and you can justify that then I'm stumped.

Oh and by the way the opitician thing a few posts above really stung especially when combined with the educating OD's bit. Ouch, but it was true.

[Darryl Meister]

I have sat in front of equipment and watched it work and seen teh level of accuracy and the low level of inaccuracy. (amazing to see the equipmet monitor minute changes in position down to fractios of fraction of a diopter)... That is why I use my own, I know where the compensation came from, I know how it works, I knwo that if it spits out a number and then I don't surface it correctly according to that number that I am not just going to go back and change the numbers to match what I have surfaced...

I think you guys are inadvertently perpetuating some of the myths surrounding free-form technology in this thread. Free-form surfacing is just a manufacturing platform. As a "technology enabler," it can potentially offer certain benefits to wearers, but the visual benefits of simply surfacing a progressive lens design directly onto a lens blank versus molding it are minimal.

For instance, there has been an emphasis on power and power accuracy in the past few posts. While some free-form lens suppliers advertise "accuracy of 0.01 D" and similar claims, these statements are often exaggerated and misunderstood. Whereas a free-form surfacing process isn't limited by the precision of hard lap tooling (typically in 0.10- or 0.12-diopter increments), I would argue that hard lap tools in a traditional surfacing process using a modern generator can produce just as accurate sphere and cylinder powers compared to soft lap polishing. For that matter, if you are worried about precision, you could always expand your inventory of tools or just cut your own lap tool for each job, although this is overkill.

Further, while a free-form lens process can replicate certain features of progressive lens designs better than traditional molding, this improvement in accuracy relies on extensive process engineering and ongoing quality control. As an example, consider the fact that the dynamics of the soft lap polishing process can distort surface features if you have not properly "tweaked" the process parameters for each job; unlike traditional polishing, in which you would generally only change your pressure and cycle time from lens to lens, CNC soft lap polishing is more complex, and can utilize up to a dozen or more different process parameters. Consequently, if you just "plug in" your new free-form generator and polisher, and start knocking out progessive lenses, you might very well find that you actually get more consistent quality from traditional, semi-finished progressive lenses.

Similarly, you are focusing quite a bit on the benefits and implementation of prescription compensation (another power consideration), although prescription compensation isn't really a benefit of free-form technology. There are semi-finished lenses available with prescription compensation, for instance, and plenty of free-form lenses without it. So it doesn't make a lot of sense to judge the merits of free-form technology based solely on how well the free-form lens supplier has compensated the prescription. In any event, if you get a compensated Rx on something that looks like a print-out from a lab calc program, it has probably been calculated using legitimate software (although this software may vary considerably in accuracy from lens supplier to lens supplier). If you get a hand-written compensated Rx or a Humphrey Lensmeter ticket, on the other hand, then you may have reason to question whether or not the compensation is correct.

On a side-note, your personal Rx compensation will generally not be especially accurate with progressive lenses, since these lenses often have non-negligible thickness, significant vertical prism, and power verification points located at significant angles to the optical axis of the lens. Consequently, your patients may not necessarily be any better off when it comes to trusting your own results.

It is this emphasis on the alleged "power accuracy" of free-form surfacing that has also brought this thread full circle to another discussion of ANSI tolerances. ANSI tolerances apply to finished spectacle lenses; they do not differentiate between finished spectacle lenses and finished spectacle lenses that cost more than other finished spectacle lenses because they were made using a really expensive generator. ;) If you expect your free-form lenses to made to a greater level of accuracy, you should come to some kind of agreement with your free-form lens supplier. Besides, if you are completely in control of your own process, you set your own quality guidelines, not ANSI. ANSI simply serves as a common benchmark that anyone can use as a starting point when considering or discussing quality guidelines.

On another side-note, progressive tolerances were originally loosened in the 1995 standard, along with aspheric lenses, because comparable ISO standards allow slightly greater tolerances for these lenses due to the more complex manufacturing processes involved. In any event, this argument swings both ways; if you, personally, feel that ANSI tolerances and conventional refracting procedures are too loose, the availability of "free-form" lenses with increased accuracy should be very appealing to you, since you are minimizing the propagation of error at one stage, at least.

In a nutshell, if you're buying a "free-form" progressive lens only because the manufacturer says that the lens surface has been made to a higher level of "accuracy," you might very well be wasting your money, in my opinion, in order to obtain a production advantage that may or may not even be realized, depending upon the processing expertise of your free-form lens supplier.

So far the information given has been nothing but marketign hype with not much in the form of technical data presented to the ECP, so the ECP's mind is left to wander and the marketing drones do such a great job of making all lens desings sound rosie unless someone puts out a good instructional or education piece describing the various benefits and HOW they are acomplished then in general ECP's are going to be slow to adopt.

This technical bulletin on Carl Zeiss Vision's free-form optimization has been available for download from OptiBoard. Other manufacturers may have similar pieces, although I have not run across any. I think the biggest problem with "digital surfacing" for eye care professionals is that very few free-form lens suppliers share exactly what they're doing to command these premium prices. Sometimes, given the obvious disconnect between the marketing organization and the research and development group with some of these companies, I wonder if they even know!

While there are some minor optical benefits to surfacing a progressive lens design directly onto the back of a lens blank, the real visual benefit of free-form technology to the wearer, in my opinion, is the ability to customize or optically optimize the lens design for the individual wearer. Although several free-form lens suppliers simply surface a basic progressive lens design onto a lens blank from a "points" file, which may actually result in performance comparable to similar semi-finished progressive lenses, there are also free-form lens suppliers out there designing completely customized lens designs in "real time" using information specific to the wearer, including prescription, frame size, position of wear geometry, viewing habits, etcetera, which can significantly improve optical performance for many wearers.

[HarryChiling]

In a nutshell, if you're buying a "free-form" progressive lens only because the manufacturer says that the lens surface has been made to a higher level of "accuracy," you might very well be wasting your money, in my opinion, in order to obtain a production advantage that may or may not even be realized, depending upon the processing expertise of your free-form lens supplier.

What the h*ll, you can agree with me on this one your a manufacturer. ;)

This technical bulletin on Carl Zeiss Vision's free-form optimization has been available for download from OptiBoard. Other manufacturers may have similar pieces, although I have not run across any. I think the biggest problem with "digital surfacing" for eye care professionals is that very few free-form lens suppliers share exactly what they're doing to command these premium prices. Sometimes, given the obvious disconnect between the marketing organization and the research and development group with some of these companies, I wonder if they even know!

That's where alot of it falls apart for me. I'm a who, what, when, where, why, and how type person and I just am not getting enough of the how. This is a short coming that can unravel all the marketing you throw at this new processing technique. All I have to do is come into an office and show someone how simple eductaion in more accurate measurements and more time spent fine tunign Rx's with a decent lens design can increase non adapts and the bottom line without paying double for a lens and BINGO I have just unraveled the whole FF game in that office. It's not just OK to offer these products haphazardly into the market the benefits and design elements need to be expressed.

If you think optician are smart enough to understand it, make an attempt at both ends of the spectrum try to provide some education to the opticinas to get them to the level needed to understand the processes being used to compensate the lenses and at the same time water down the level of detail that is explained about the process. Or and this is what's turning me off to the whole idea hand me a lollipop and ask where's the doctor you wouldn't understand this. Guess who sells it. :D