# Optical Forums > Progressive Lens Discussion Forum >  Time for some clarity on progressive technology...

## drk

Ok, things are moving faster than I can keep up with. Can we start a thread that overviews the basics of the changes going on in the progressive world?

Topics:
1.) Back surface progressives
1a.) Full progression on back surface
1b.) Part on front, part on back
2.) Individualized progressives
3.) Wavefront-corrected progressives
3a.) Corrected for wearer's abberations
3b.) Corrected for lens' abberations.
4.) Freeform progressives

Let's start with #1.

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## drk

Back surface progressives: (please help me edit this, as it is not a research paper, but a community effort.)

The idea, I believe, is that if the progressive zone is closer to the eye, the field of view will be larger.

But the problem is that the sphere and cylinder power cannot be placed on the front surface (for various adaptation reasons), so the progressive curves and the sphero-cylinder curves have to be cut simultaneously.

Examples of all on back design: Proceed Internal from Seiko. Multigressive from Rodenstock.

Examples of front and back progression: Definity.

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## drk

Individualized progressives: (Help me out, here)

Since with back surface progressives, you are cutting unique surfaces, then you might as well vary the parameters to create a specific lens. 

Examples:
*insets can be more/less depending on distance pd and prismatic power of lens
*distribution of unwanted astigmatism can be maximized for each add power
*design can be maximized for specified vertex distance, or pantoscopic tilt, or even frame wrap ("position of wear")
*design can somehow utilize information about head and eye movements (harder or softer, shorter or longer corridor, etc.)
*design can take into account fitting height being used

This requires a free-form, or 3-axis generator.
The customization occurs on back (and front?) of lens.
This process saves labs from having to stock many lens types.

Some free-form designs utilize "generic" data, and others require "patient-specific" data from various in-office measuring devices.
Ipseo: patient specific
Gradal Individual: patient specific
Shamir Autograph:?
Sola One HD: generic population data?

It seems as though the input of these patient-specific data guides some software that maximizes some effects and minimizes others to achieve best effect.  It's almost as though there is a computer analyzing data, and then spitting out the best design, not unlike what seasoned dispensers try to do when choosing between "pre-made" designs.

The upshot should be that, on the whole, the patient population should get better vision more consistently by virtue of "automatic design matching".

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## drk

Wavefront corrected progressives:

Corrected for wearer's higher order aberrations: 
The Z-View from Ophthonics is the only one in this category that I'm aware of, and it's SV only, I believe.

Corrected for lens's higher-order aberrations:
I'll cut and paste from James Sheedy, O.D.'s newsletter:


NEWS 

ESSILOR DEBUTS WAVEFRONT-CORRECTED SPECTACLE LENS 
Essilor of America has announced the launch of two new lenses, Varilux Physio and Varilux Physio 360°, which use wavefront technology to reduce or eliminate higher order aberrations found on the progressive lens surface. The Wavefront Advanced Vision Enhancement (WAVE) technology used to create the lenses has three components: wavefront instrumentation to measure the lens wavefront and reduce lens-induced higher order aberration; a patented calculation engine to optimize lens design; and 360° Digital Surfacing, which is used to create lens molds and back surface curves with the level of precision necessary to correct minute wavefront errors. According to Essilor, 360° Digital Surfacing allows creation of a complex surface with accuracy to 0.1 microns. Both the Varilux Physio and Varilux Physio 360° feature a wavefront-enhanced front surface. The Varilux Physio 360° also features a digitally surfaced back side customized to complement the front surface. Essilor claims that the 
new technology will, for the first time, reduce previously uncorrectable higher order aberrations inherent in progressive lens designs and provide enhanced vision at all distances and light levels. 

EDITORS NOTE: In this application, Essilor uses wavefront technology to correct the higher order aberration inherent in all prior progressive lenses. This should not be confused with another technology that is used by Ophthonix, Inc. to produce iZon wavefront guided lenses. The iZon product uses wavefront technology to measure patients vision and aims to correct higher order aberrations in the patients own eye. Ophthonixs first product to come on the market is a single vision lens. 




This one has me stumped. I understand that spherical aberration is inheirent in all lenses, as well as chromatic abb., coma, curvature of field, etc. (the seven Seidel aberrations). Are these being referred to as "higher order"? From refractive surgery technology, we also discuss "trefoil, quadrifoil, etc.", which are esoteric names for esoteric types of blur, essentially. Are we to assume that ophthalmic lenses also have such aberrations? Or, are we simply talking about the main issue, which is spherical aberration?

I think it's going to be important to understand the degree to which these aberrations are affecting patients, first, before we buy into the brave-new-world marketing hype that is, essentially, way over the top of most of our heads. We are probably talking a tenth of a diopter, here! 

My cynical position tells me that, until proven otherwise, wavefront correction in spectacle lenses can be rendered useless by real-world factors, such as:
1.) Even minimally incorrect glazing
2.) Variation in position of wear from frames' flexibility, or lack of perfect adjustment ("registration issues")

I also worry that a -0.25D surfacing error, or minimal, minimal refracting error, or even an oldster's naturally increasing internal higher-order-abberations may make the whole wavefront aspect of Varilux Physio a massive waste. It'd be like telling time with an atomic clock.

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## pauly47

Do you think that the Definity and Physio are the same (like Chevy and GM).  A few labs said it's same technology but different coatings (Definity avail with Gemcoat and Physio with Crizal)?  hmmmmm....

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## rhondaboman

Pauly

My understanding is that the Definity starts out with a Plano lens.  Both sides are ground to achieve a 50% wider useable area by splitting the add power between the front and back surfaces.  Again, this a software designed lens but instead of a corrected curve theory mold or a digitally designed mold (Physio), for the front surface, it is ground like the backside.

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## drk

Thanks for participating.

I added a 4th category, "freeform" lenses.
(Note that lenses may exist in several categories.)

A "freeform" lens, then, is a lens that starts out with no surface features, and is cut on a job-by-job basis, but not necessarily is "customized" for the wearer. Adds can be on back surface, this way.

Example: Definity

(Maybe, though, back surface progressives are a subset of freeform progressives, a subcategory.)

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## Andrew Weiss

Comment about Multigressiv:

The lens uses as its front surface the Rodenstock Life 2 design.  This is a standardized molded design, referred to by Rodenstock as fully aspheric and with "horizontal" and "vertical" symmetry and offsetting the corridor and reading area based on the prescription values.  The back surface is custom-ground on a computer-driven surfacing machine.  The software calculates how to keep the front surface design in its most "perfect" form by compensating for the abberations which would be caused by the individual's prescription.  In my experience, this lens is the best for people with significant astimatism, particularly at an oblique axis, and anisomatropia (?sp?), as well as being an excellent all-purpose progressive.  If only they had the machine in America (Rodenstock will not let it out of Regensberg, Germany). :Mad: 

I really wonder whether Physio's wave-front design will be any significant improvement over what the Multigressiv already does so well . . .  Uncle Fester took in an order for our first Physio Saturday, so I'll have a chance to look at the lens sometime this week  :Eek:

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## AWTECH

> Individualized progressives: (Help me out, here)
> 
> Since with back surface progressives, you are cutting unique surfaces, then you might as well vary the parameters to create a specific lens. 
> 
> Examples:
> *insets can be more/less depending on distance pd and prismatic power of lens
> *distribution of unwanted astigmatism can be maximized for each add power
> *design can be maximized for specified vertex distance, or pantoscopic tilt, or even frame wrap ("position of wear")
> *design can somehow utilize information about head and eye movements (harder or softer, shorter or longer corridor, etc.)
> ...


All of your points seem to be on target.  There is currently not any clear definition to the Freefrom lens subject.

I will try to help you with your thought process and point out a few of the reasons for some of the marketing speak.

1-Freeform relates to the ability to cut almost any non-spherical surface desired,(within reason).  This can be done on the front side or the backside or both.  Freeform is not a lens design.  I have seen a Playboy bunny logo produced using freeform machines, however this does mean you can see by using such a lens, it was done to show the unique ability of the equipment compared to machines that can only make spherical cuts.

2-Lens designs that are programed for use with freeform equipment can actually calculate the surface for each individual design for each patient and frame selected in a very short period of time.  This then produces the surface data point files. (These files are thousands of x,y,z data points needed for the freeform machine to operate.

3-These programs used to produce freeform lenses using advanced individual lens designs are very complex and can take into account any variable that the lens design team can figure out how to have entered and then converted into usable data for each individual lens.  These programs are quite complex as you can imagine.  Knowing the lens shape including the A and B measurement allows the lens computer designer team to have the program calculate the lens surface to be the thinest possible.

4- Position of wear can be included in the lens calculations, wrap, panto tilt, and vertex distance.  The PD is critical as well as the optical center for these calculations since elements like the wrap angle of the frame are not needed but the wrap angle of the frame center to the optical center is what is needed for to calculate the corrections needed.

5- Frontside freeform, backside freeform or both sides freeformed? Well when you get through the marketing materials one aspect of freeform designs that is not included in the marketing materials of freeform lenses that have both surfaces non-spherical is this. 

"We would prefer to have produced a lens with a backside freeform design using a spherical front surface, however such an approach is covered by a patent, and we have not been able to obtain permission to produce lenses utilizing this approach." 

For many the use of non-spherical surfaces on both sides is an approach that they can use to produce a lens, may this is not their first choice but a legal way to enter the market.

6- In addition to better designs for the patient a great freeform lens design program has the ability to take into account many factors that a PAL that is cast on the front can not.  The cast lens PAL system uses between 65-90 different semi-finished lens blanks and from this the choices are determined by various spherical cuts to the correct lens.  Any design that falls in between one of these blanks can not be made.  With a great freeform lens design program the possiblities are almost endless.  Over 2,000,000 different PAL designs are possible using one program.

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## QDO1

so now what we all really knew is out in the open

Freeform, is like Aspheric - it is a word that is miss used

Aspherical means non spherical.  Freeform means cut with a "free tool"

The following are possible with freeform surfacing:

+1.00 DS spherical 70 blank CR39 - just like a moulded lens
+1.00 DS Aspheric 70 blank CR39 with the most appaling optics imaginable 

ranging to the very best in optics...

When we specifically look at progressives, perhaps what we need is computer software from the manufacturers, that links to a frame tracer, and shows the design each algorythm produces for us, maybee in terms of iso-cylinders.  Then as professional dispensers, we can order what we want

this software could have say 5 screen options - describing the different abberations at each point on the lens

To me, dispensing "free-form" is like peeing in the wind - we just hope the algorythm keeps getting it right - and we never get a idea of what we really ordered untill it comes back

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## Laurie

I believe that AWTECH is correct with his/her definition of freeform.

It is a technology, not a design.


A good lens design on the front is better on the back

A great lens design on the front is fantastic on the back.

It could be done on  the front (as in mold making) or on the back.  If a lab generates a PAL using an X Y Z file system on the back, from a spherical front base, it is a back surface PAL using freeform technology.

I think splitting between front and back, wavefront, dual adds or otherwise, is an opportunity for greater errors, given the human element.

I would sum it up as follows:

Front mold digital design, back surface spherical = good

Front surface spherical surface, back surface digital mold (freeform) = better

Split between the front and back, in theory sounds good, but opens up greater possibility of increased aberrations due to human error.

: )

Laurie

PS:  Dr K:  it is my understanding that they are referring to higher order coma aberration...hardly noticable to the brain.

Still, as far as we can drive technology, the most commonly complained about aberrations are spherical aberration and chromatic aberration.  A material with a better abbe value (trivex) will still out perform a lens that corrects for higher order aberrations, and is made in poly, for example...correcting an obscure higher order aberration, and ignoring chromatism.

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## Chris Ryser

> *Split between the front and back, in theory sounds good, but opens up greater possibility of increased aberrations due to human error.*


How about having distorted areas on both surfaces................or shall I say surface astigmatism.

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## drk

Thanks to all contributors!

Then we can say that back side progressive curves are superior to front side or "dual adds"?  I think that's intuitive.

Has anyone read the marketing claim that Definity's Dual Add technology allows (paraphrase): "aberrations from the front surface to be cancelled out by curves cut on the back surface"?  They almost make it sound like they can reduce aberrations better with a "dual add" than a "single surface" add.  I don't think I accept this, as I am taking it to mean.

Does this mean Rodenstock has the patent to the spherical front/backside progressive lens, or is it Seiko's?

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## Laurie

Hi Dr. K,

I make the same summary as you in regard to design.  A front spherical, back freeform/XYZ file/PAL is the best.

The Shamir Autograph uses a front spherical/back XYZ/freeform/PAL and may very well hold the patent.  It is my understanding that they are the only ones actually making them in the US with partnering labs.

Hi Chris,

Yes, it is possible to have aberrations on both surfaces, especially when the front surface is a molded PAL, and the back is a digitally induced XYZ file.  The room for error is greater than if it had been a front surface molded PAL with spherical curves (toric base curves and cross curves) or a spherical front (Base Curve) with a digitally induced XYZ file on the back (PAL design, freeform technology).


: )

Laurie

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## drk

Laurie, you know your stuff.

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## Andrew Weiss

Laurie, does this mean the Autograph puts the progressive add on the back surface? or does it use the Multigressiv approach and use a standardized, molded front surface with the add and then freeform-grind the back surface?  Do you know if they use similar parameters as Rodenstock does in designing the back surface for each lens?

I've had such good success with the Multigressiv, it would be nice to know there's a US-made alternative with similar characteristics.

drk, thanks for starting this thread.  Great education.  As to what the Definity does or doesn't do, I can tell you based on wearing them that it has very little, if any, abberation in either the distance peripheral or in the intermediate/near peripheral.  Part of this, I believe, is due to the "ground view advantage" design, which shelves off the add toward the periphery and provides actual intermediate vision at the edges of the reading area (after going through a relatively benign blur-zone), and distance vision below the reading area if the height exceeds 26mm (I think).  I don't know if this is an accurate comparison, but I think of it as a round-seg type design done in a progressive.

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## AWTECH

The first US Patent issued covering this issue is  US Patent 6,019,470.

This Patent issue is real and I would not recommend selling lenses produced with a backside PAL unless these are manufactured outside of the US.

This Patent is not licensed to Shamir for the Autograph as I understand.

I would like to thank Laurie for the confirmation of my belief.  I do not understand why Shamir is currently attempting to have their partner labs produce these backside PAL lenses without the assignment of the rights to do so.  It is my understanding that Shamir does not have such rights. 
This is a new area for optical lens production and is quite different from other PAL designs in the ability to produce very customized lenses.

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## For-Life

Here is an important question:

How much value does each addition have.

For instance, lets assume that the Physio costs $100 to the patient (the product is not in Canada eh yet, so I am making that number up).  Now, lets assume the product is better than the Panamic.  Finally, what is the value?  Meaning will the additional cost of the Physio be greater than, equal to, or less than the Panamic.

We can use that for all of the lenses.

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## Laurie

Hello Again,

To Dr. K:  Thanks! *blush*  *blush*  

: )

To Andrew W:  Yes, they are adding the PAL to the back surface.  I hesitate to answer your other question, but will forward it to the lens (geeks) engineers at Shamir Insight in San Diego and Israel for further clarification.

To AWTECH:  While I am not a spokesperson for Shamir Insight's legal holdings, I can tell you that their team is outrageously ethical.  They won't so much as make a photo copy of an educational handout or article, respecting copyright issues, etc.  I will look into your question and report back as soon as I have first party information.

Laurie

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## drk

ForLife:
The Physio is priced a trifle higher than Panamic, from what I've seen.

Is the question: are we getting diminishing returns on investment? A legitimate question!

Also, I think the comment that was made that a "low aberration" design in a "high aberration" material makes sense.

Andrew, I think the Definity must be good, based on what you say and what I've read. What is your add power, BTW? You look like about a +1.00;)

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## AWTECH

Laurie;



> The Shamir Autograph uses a front spherical/back XYZ/freeform/PAL and may very well hold the patent. It is my understanding that they are the only ones actually making them in the US with partnering labs.


In the above you state that Shamir may very well hold the patent.  Which they certainly do not hold the original patent for backside progressive maintaining a spherical front surface.




> While I am not a spokesperson for Shamir Insight's legal holdings, I can tell you that their team is outrageously ethical. They won't so much as make a photo copy of an educational handout or article, respecting copyright issues, etc. I will look into your question and report back as soon as I have first party information.


I await your findings.  In another thread someone else reports this patent issue has been resolved.  I have not been able to confirm this resolution.  I would think if Shamir does have a clearly defined resolution that the information would be available.

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## shrimper~dan

It is my understanding that there are overlapping patents issued covering the technique of spherical front/PAL back. One is owned by Seiko-Epson, the other is owned by Carl Zeiss Vision. Seiko-Epson has given lens companies such as Shamir the right to use this technique, for a small fee, _<wholesale pricing removed>_. Unfortunately, CZV has not. This issue remains unresolved and is currently the biggest obstacle to this technology coming to market.

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## Chris Ryser

Make a search on the US patent office and you will find out. I Zeiss has a patent in Germany only it would not be valid here if no application has been made.

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## QDO1

> Make a search on the US patent office and you will find out. I Zeiss has a patent in Germany only it would not be valid here if no application has been made.


Well it might be worth remembering Zeiss and Rodenstock are German companies, and Essilor French, and Hoya, Nikon, Seiko and Pentax Japanese... As much as the US believe they are the centre of the world, in Optics, they clearly are not.  The US patent office isnt the hub of the world either

Perhaps thats why Rodenstock and Essilor regularlary release lenses into the european markets years before they get to the US

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## Bobie

Hi QD1 , 
I would like to discuss in this topic , but I can't , because my parent , my brother are fear from the word from some big man in Thailand and my member at www.apcthai.com have to stop our webboard that may be have some thing about ESSILO.... .

I will try to fight with all strength for freedom of our webboard.

Sometime , in Thailand , the freedom is so far , but I will be back as soon as possible.

If I have to do my job in jail , I will do and never regret ,
may be I will be the optiker in jail and fitting PALs for prisoner around the world.

Someday , we will not have PALs Mafia in our world anymore , we will see.

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## Laurie

Hi QDO1,

I think Chris was referring to US patents, as we were discussing the production of freeform PALs in the US.  Is there such a thing as a worldwide patent?  I would guess that a manufacturer must apply for a patent in each country they wish to sell in?

(If I am wrong, please correct me...this is not my area of expertise).

: )

Laurie

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## Pete Hanlin

Wow, a great deal of discussion (which I've not had the opportunity to read in entirety) on this thread!

A good lens design on the front is better on the back.  A great lens design on the front is fantastic on the back.
Theoretically speaking, this is true- but in actual wear, it doesn't bear out.  Case in point, Varilux Ipseo is currently surfaced with all power on the backside (both distance Rx and progression).  The front is spherical.  In its original form, the progression was placed on the front and the distance Rx on the back.  Wearer experience between the two yields no difference in actual visual perception.  Perhaps one could argue that Varilux Ipseo isn't a "good" or "great" design- I suppose it depends upon whatever measures one uses to determine the quality of the design- based on wearer tests, Varilux Ipseo seems to be a pretty great design.

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## AWTECH

Pete, can you comment on the Ipseo and the Seiko-Epson patent.  Since this lens uses a spherical front surface and a digital back surface, do you know if Essilor has a patent use agreement from Seiko-Epson.

Why was the Ipseo design changed from the front and backside to just the backsurface?

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## Darryl Meister

Regarding patents on back-side free-form progressive lenses, since this issue keeps coming up (especially in the context of Shamir), Zeiss has a patent on this technology for certain. I'm not aware of any Shamir patents that supersede this one.

Regarding the preferred use of free-form front-surface versus free-form back-surface progressive lenses, here are a few (but not all) of the advantages and disadvantages to both approaches:
Back-side designs probably reduce distortion slightly, since the magnification differences due to strictly to the front surface curvature are eliminated on the back.Back-side designs increase the field of view slightly, since the zones of clear vision are brought slightly closer to the eye.Back-side designs only have to be surfaced once, which cuts down on production time, quality issues, and so on.Front-side designs may require less eye movement to reach the near zone, since the near zone is brought closer to the eye.Front-side designs may have a broader prescription range, since it is often more difficult to produce higher cyls in complex surfaces with a free-form generating system.Regarding, levels of "individualization," they vary considerably. AWTECH has summed up many of the differences already. Here are just a few (but, again, not all) of the possibilities that you are likely to run into:
Free-form lens with no individualized optimization (e.g., the original _Definity_ lens)Free-form lens with a prescription "tweak" at the distance or near reference pointsFree-form lens with full prescription optimization over the entire lens based on _average_ parameters, with or without the "tweak" at the reference pointsFree-form lens with full prescription optimization over the entire lens based on _specified_ parameters (requires additional measurements)Free-form lens with design customization (i.e., the viewing zone configuration, periphery design, and/or corridor length is modified)Free-form lens with design customization and full prescription optimization, with or without the "tweak" at the reference pointsNote that any lens with a prescription "tweak" at the distance and/or near reference points will require a _Compensated Rx_ in order to verify the original prescription.

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## AWTECH

Laurie writes;




> Is there such a thing as a worldwide patent?


No there is no such worldwide patent. Each country that offers patent protection such as the US or Japan require the filing for the patent within that country.  In recent years an exception in Europe has evolved due to the EU.  This follows the common currency the Euro. No more Peso, Lire, Francs, DM etc., I can not from memory recall what European Countries can be handled with one application but I believe that this is controlled from Spain.

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## Andrew Weiss

> Andrew, I think the Definity must be good, based on what you say and what I've read. What is your add power, BTW? You look like about a +1.00;)


Yeah, right  :Rolleyes:   I'm 61, my friend.  My add is 2.50.  (when you look at the my avatar photo, Fester says he's the one in the foreground).

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## lensgeek

[QUOTE=Andrew Weiss]Laurie, does this mean the Autograph puts the progressive add on the back surface? or does it use the Multigressiv approach and use a standardized, molded front surface with the add and then freeform-grind the back surface? Do you know if they use similar parameters as Rodenstock does in designing the back surface for each lens?

**********************************************************
Please let me clarify one thing.... "a standardized, molded front surface with the add and then freeform-grinding the back surface" 
falls into a catagory of "half-freeform" (not a progressive technology)
.....kind of like a woman being "half pregnant"........
It is what is is, or it isn't!

this, by the way, is a common misconception...

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## AWTECH

The Shamir Autograph uses the back surface for the Rx, the front is spherical, from what I have seen of this lens in the past. They may have changed this to avoid a potential patent problem.

As for the term Freeform and what it means, I think the meaning is being formed as this concept slowly comes into the market place.

Freeform can mean almost anything. Think about it "Free" no restrictions and "Form" shape. I would say a shape with no restrictions is the actual meaning. In other threads the word Freeform has been discussed and I have compared it to Aspheric. 
Example:
A-Walk into any retail optical store and ask an optician what Aspheric means and you will get an answer talking about a design of a lens that is non spherical in one meridian used to give good vision with a thinner lens.
B-Walk into a senior class at any engineering college and ask what Aspheric means and I will be 99.9% say non-spherical.

The same is happening to the word Freeform in the Optician world. A Freefrom lens may come to mean:
"The description of the surface of a lens produced using x,y,z data point files on one surface."

Using this definition a molded front surface lens that is processed on the backsurface with a data point file could be called a Freeform lens.

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## lensgeek

AWTECH: You seem to be on target in your description of freeform until the last statement....if, as you stated, "x y z data points are applied on one surface".....this would include a progressive design specific to the data in the x y points.....therefore, pre-made molds are not needed... (one less step in degrading the original mathematical formula of the design)

Freeform technology applies x y z data points at the same time the Rx is applied.

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## AWTECH

In a previous post I said:




> The same is happening to the word Freeform in the Optician world. A Freefrom lens may come to mean:
> "The description of the surface of a lens produced using x,y,z data point files on one surface."


Lensgeek then commented:




> You seem to be on target in your description of freeform until the last statement....if, as you stated, "x y z data points are applied on one surface".....this would include a progressive design specific to the data in the x y points.....therefore, pre-made molds are not needed... (one less step in degrading the original mathematical formula of the design)


MY REVISED VERSION OF WHAT FREEFORM MAY COME TO MEAN TO OPTICIANS

Freeform could come to mean 

"The description of the surface of a lens produced using x,y,z data point files configured to produce a progressive lens." 

I do not think the work Freeform will be limited to one surface.

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## Darryl Meister

> I do not think the work Freeform will be limited to one surface.


Nor is it limited to progressive surfaces. You might check out this article on free-form and its applications, if you haven't already.

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## AWTECH

Yes Darryl you are correct:




> Nor is it limited to progressive surfaces.


However, my point was that the direction I see the word taking on in the world of Optician's, is connected to progressives. The word "Freeform" is in the early stages of what happened to the word "Aspheric". Aspheric means something completely different to an optician than it does to an engineer.

My guess is in two years you ask an optican who has been in the field for only one year what Freeform means and they will include the word progressive.

This is only my opinon, it is not what the word actually means to anyone outside of the opticians world.

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## Darryl Meister

> However, my point was that the direction I see the word taking on in the world of Optician's, is connected to progressives... My guess is in two years you ask an optican who has been in the field for only one year what Freeform means and they will include the word progressive.


All the more reason for people like us to help clarify such terms. ;)

Ultimately, a "free-form" lens is simply a lens made using a free-form generator, and can include lenses as simple as a basic sphere. There is nothing inherently special about a free-form lens, and you can actually make any "free-form design" in a semi-finished form. (For that matter, the machines used to produce semi-finished molds are very similar to free-form generators.)

The real benefit of free-form technology comes from the ability to create -- or customize -- a lens design for a _specific_ customer. This _isn't_ something you can do with traditional semi-finished manufacturing. However, the benefit versus cost of customizing a lens design is better for progressive lenses, which is why this technology is often used for progressives instead of, say, single vision lenses.

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## AWTECH

Darryl you make great points:



> Ultimately, a "free-form" lens is simply a lens made using a free-form generator, and can include lenses as simple as a basic sphere. There is nothing inherently special about a free-form lens, and you can actually make any "free-form design" in a semi-finished form. (For that matter, the machines used to produce semi-finished molds are very similar to free-form generators.)
> 
> The real benefit of free-form technology comes from the ability to create -- or customize -- a lens design for a _specific_ customer. This _isn't_ something you can do with traditional semi-finished manufacturing. However, the benefit versus cost of customizing a lens design is better for progressive lenses, which is why this technology is often used for progressives instead of, say, single vision lenses.


My company actually specializes in Freeform single vision optimized for our own ICE-TECH Advanced Polarized lens.  We call it Thin-ICE Technology which is a freeform individualized lens designed to be thinner and more accurate, allowing higher power Rx lenses to be fitted with 6 or 8 base front curves.  This as you point out is a more expensive process than traditional lens production but for the segment of the market that wants and/or needs such specialized lenses the concept of freeform allows such lenses to be produced.  One of the expense items in these limited production lens offerings is the software development amortization.  Microsoft doesn't make a $299 lens design software package.

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## eyeboy

I rang Shamir today, who told me that the Autograph is front surface progressive, but has been made to be worked in flatter curves i.e better cosmetically whilst giving the same performance as a steeper curve.

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## AWTECH

Eyeboy said:


> I rang Shamir today, who told me that the Autograph is front surface progressive, but has been made to be worked in flatter curves i.e better cosmetically whilst giving the same performance as a steeper curve.


You might want to call Shamir back and ask for a technical person familiar with their freeform designs:

http://www.shamir.co.il/products_1.asp

This is the link to Shamirs website that says the Autograph is a backside design.

As I said earlier in this thread my company only does freeform and I am quite familiar with many of the designs in the market. When a company primarily does traditional front side progressives and only has the freeform as small portion of there offerings it is difficult to train everyone on the differences.

It is information like this that is passed on from manufacturers to opticans and then passed on to consumers that creates non factual infomation in the market place.

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## eyeboy

> Eyeboy said: 
> 
> You might want to call Shamir back and ask for a technical person familiar with their freeform designs:
> 
> http://www.shamir.co.il/products_1.asp
> 
> This is the link to Shamirs website that says the Autograph is a backside design.
> 
> As I said earlier in this thread my company only does freeform and I am quite familiar with many of the designs in the market. When a company primarily does traditional front side progressives and only has the freeform as small portion of there offerings it is difficult to train everyone on the differences.
> ...


:hammer: Rechecked the price list and I'm wrong the Autograph is backside, it is the Creation which is frontside Free form designed varifocal. since you know so much about the free-form stuff how is frontside free-form design better than your average front side progressive?

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## Darryl Meister

> it is the Creation which is frontside Free form designed varifocal.


We call those "semi-finished" progressive lenses. ;)

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## dary

Rodenstock and Seiko are the first who made double aspheric progressives.

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## eyeboy

> We call those "semi-finished" progressive lenses. ;)


Yeah I know but this is what they told me, that this lens design allows for flatter lenses???0

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## AWTECH

This Shamir Creation maybe a copy (Creation) of the Seiko design using multiple spherical front base curves.  Seiko uses 10 different spherical front base curves for MR-10 1.67 lenses.  This produces a very thin lens and there are over 2,500,000 individual lens designs available, (without counting any with prism).

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## Darryl Meister

So, are you guys saying that each Shamir Creation is produced at the laboratory using a free-form generator (because my impression was that labs order it as a semi-finished lens blank and then surface it normally) or that Shamir is actually manually surfacing each and every lens blank before they send them to the lab (which would be very cost-prohibitive)?

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## Jubilee

My understanding after talking to our local lab, is that the lens is similar to the Physio. Optimized front surface is created through free form technology, using regular back side surfacing methods..


Cassandra

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## Darryl Meister

Varilux Physio uses a semi-finished progressive lens surface. While the molds used to manufacture Physio may have been produced using "free-form" technology, this is true for virtualy all semi-finished progressive lenses.

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## AWTECH

Shamir Creation does appear to be a traditional PAL front surface lens with the lab surfacing the back.  The claim on their web site regarding this lens is that it uses 6 different base curves to create a thinner lens.

As I stated before the Seiko method of 10 different base curves does offer a thinner lens design throughout the prescription range.

I was at first under the impression that this product was also freeform produced.

It seems that some lens manufacturers are trying to capitalize on the buzz of freeform by claiming their traditional PAL designs are made in molds using freeform technology.  

As Darryl points out this the method used by all PAL manufactureres to produce their molds.

Nothing new and different just a different way of saying we have a great new lens design.

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## Chris Ryser

> *I can not from memory recall what European Countries can be handled with one application but I believe that this is controlled from Spain.*


European patents are filed in Munich Germany. Once they have passed the procedure.......about 2 years.................they are granted. Following that you can file for patent protection in each individual country of the European comminuty you wish. That involves an initial fee for each country and a yearly upkeep fee.

Worldwide patents do not exist...........patents have to be filed in each individual country plus yearly upkeep fees, where you want to have protection.

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## Samuel Jong

> Varilux Physio uses a semi-finished progressive lens surface. While the molds used to manufacture Physio may have been produced using "free-form" technology, this is true for virtualy all semi-finished progressive lenses.


Is Gradal Individual also using "free-form technology"? Thanks.

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## Darryl Meister

Gradal Individual is a _true_ "free-form" lens in the sense that each lens is custom-designed and manufactured to wearer specifications using a free-form generator.

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## Samuel Jong

> Gradal Individual is a _true_ "free-form" lens in the sense that each lens is custom-designed and manufactured to wearer specifications using a free-form generator.


Thanks a lot Darryl.

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## lensgeek

Shamir's Creation along with Varilux' Physio are semi-finished progressive lenses. Both have eliminated the "master mold" or "mechanical mold" when applying the mathematical design directly to the production (glass) molds...bypassing the ceramic mold process will produce a progressive lens with higher resolution due to some degradation which can occur while continually "copying" a design from a ceramic master to a glass production mold....

However, extending a base curve selection gives a wide perscription range a chance to be matched to a more appropriate base curve, resulting in _both_ optical accuracy and a flatter profile.....

Bottom-line...many traditional semi-finished progressive lenses have proven themselves to be "good" products...digitally applying the design via "freeform optics" will produce a "better" product...without a doubt, full customization through freeform technology are the "best"

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## Darryl Meister

> Shamir's Creation along with Varilux' Physio are semi-finished progressive lenses. Both have eliminated the "master mold" or "mechanical mold" when applying the mathematical design directly to the production (glass) molds...bypassing the ceramic mold process will produce a progressive lens with higher resolution due to some degradation which can occur while continually "copying" a design from a ceramic master to a glass production mold


Good points, but keep in mind that:

1) Metal molds for many polycarbonate progressive lenses have been cut directly for decades, yet no one ever claimed that this provided a meaningful benefit to the wearer.

2) Zeiss has already been grinding glass molds for plastics directly using free-form generators for years. So neither Creation nor Physio were the first to do this, even in hard resin.

3) You still sacrifice some degree of design resolution using a free-form process since the mold must be polished, which -- depending upon the polishing method and starting smoothness of the surface -- can still result in departures from the desired lens form. Though, admittedly, improvements in the surface quality off free-form generators has improved over the years. Further, the loss in resolution using a former is probably quite small compared to the more "global design" considerations, such as the configuration of the viewing zones, corridor, and design of periphery.

4) To say that the design is "continually copied" from a ceramic former insinuates that copies are being made of copies, which is not the case. Each new mold is produced from the original master, so there is no propogation of error or anything like that.

5) Even if you use a free-form generator to produce glass molds, you are still casting the lenses for semi-finished lens blanks. Consequently, you are still going to see changes in the lens design as a result of shrinkage and other manufacturing variations. This isn't necessarily the case when directly surfacing the design to the lens blank (assuming your process is carefully controlled). Also, following your line of thought, one could then argue that a "free-form" progressive lens surface produced entirely using a free-form process should be better than a comparable "free-form" progressive lens using a semi-finished progressive front with an optimized free-form back surface.

6) I still feel that this language is exploiting to some degree a misconception regarding the term _free-form_. "Free-form technology" has come to be associated with _customized_ progressive lenses that have been designed and optically optimized for the individual wearer's prescription and fitting parameters. However, this is not always the case for so-called "free-form" lenses (for example, simple "point files," even surfaced directly using a free-form generator, are not customized). And it is certainly _never_ the case with semi-finished lenses.

That said, now that everyone else is using such language, we'll almost certainly be forced to follow suit. Just like we all had to after one particular lens manufacturer started describing their 1.66 high-index lenses as "1.67" lenses in the US a few years back. ;)




> However, extending a base curve selection gives a wide perscription range a chance to be matched to a more appropriate base curve, resulting in _both_ optical accuracy and a flatter profile.....


I agree. But this has nothing to do with the manufacturing process, nor the quality or implementation of the lens design. It really boils down to a sales and marketing choice: Do you want a more manageable inventory or more precise optics? Nowadays, most manufacturers try to strike a compromise between the two.

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## Michael Walach

Free Form Surfacing Does Not Reffer To A "free Tool", Which I Do Not Undestand What Exactly You Would Be Reffering To, But Rather To Surfacing Process Where The Surface Of The Lens Can Not Be Defined By One Single Algorithm, But Rather Extrapolation Of Various Algorithms Tangenialy Compiled Into One Surface. Quite Common Process The In Machining Industry, Accurately Definable,  And Effective.  The Way To Go In The Ophthalmic Lens Processing Profession!

Michael Walach
Quest Optical Specialty Lab

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## lensgeek

Darryl...Thanks for responding to my recent post. In all due respect to your optical expertise, please allow me to clarify any misconceptions or misunderstandings.
It would certainly be difficult to compare a semi-finished design processed from a polycarbonate vs hard resin monomer...I should have specified hard resin/higher index monomers when comparing degradation due to continual casting....
I did not claim that Essilor or Shamir were the first to digitally apply a progressive design to glass production molds, although I do not agree that this process is the "norm"..these two manufacturers were compared in a thread to which I responded...
When referring to the original "master mold" I did not state that copies were made from copies...simply, the original master mold will degradate over time as well as the glass molds produced from it after repeated "casting"...I agree that a "freeform" generated glass mold will undoubedly lose resolution over time.... 
I will still stand firm on my belief that a "freeform surface" produced entirely using a "freeform process" is better than a comparable "freeform progressive" lens using a semi-finished progressive front with an optimized "freeform" back-surface for 2 reasons...
1.) Full customization - allowing frame and personal measurements into the design equasion.
2.) No margin for "human error" in re-aligning/blocking a semi-finished digital design prior to surfacing a "freeform back surface....
Thanks for your comments....you keep me on my toes!!   Respectfully, Lensgeek

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## Darryl Meister

Lensgeek, I want to preface my response by saying that I certainly appreciate the fact that you understand these issues well enough to pose some interesting points for discussion. The forum certainly benefits from this kind of information and debate.




> I should have specified hard resin/higher index monomers when comparing degradation due to continual casting....When referring to the original "master mold" I did not state that copies were made from copies...simply, the original master mold will degradate over time as well as the glass molds produced from it after repeated "casting"...


Then perhaps I misunderstood the point you meant to convey when you stated that "...bypassing the ceramic mold process will produce a progressive lens with higher resolution due to some degradation which can occur while continually 'copying' a design from a ceramic master to a glass production mold...." After all, any changes that occur as a result of continued casting will affect molds cut directly from a free-form generator just as quickly as molds cut from a ceramic former. Further, both of these lenses are still cast traditionally, so neither represents an actual free-form surfaced lens blank (even in the free-form" version, Varilux Physio 360 still uses a semi-finished progressive lens surface -- though, in my opinon, this approach is not without its advantages). 




> I did not claim that Essilor or Shamir were the first to digitally apply a progressive design to glass production molds, although I do not agree that this process is the "norm"..these two manufacturers were compared in a thread to which I responded...


Now, I am certainly not trying to pick on Essilor or anyone else. I happen to think very highly of Essilor, their products, and their people, and I generally don't like to involve myself in product-specific conversations like this. My point was only that several manufacturers are now attempting to differentiate their products using this terminology, though it actually describes a technology that has been in place for many years. (Free-form cutting, for instance, _is_ the "norm" for the second most popular lens material in use today, polycarbonate, and is used at some stage for every progressive lens sold.)

You used these two particular products as examples, and suggested that they achieve better design "resolution" than other semi-finished progressive lenses. While I would be quick to point out as a Zeiss employee that Zeiss has been directly cutting glass molds for progressive lenses for many years now and that the progressive surface of our free-form lenses are _directly surfaced_ if I simply wanted to "play those cards," I think it is considerably more important to talk about what free-form can accomplish for the _wearer_ in terms of _customization_. I don't even agree that the free-form manufacturing process is inherently far superior to traditional casting, but -- even if it were -- the differences to the wearer would be negligible compared to a free-form lens that starts with a high quality progressive lens design and then improves its performance using a good optimization program.

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## lensgeek

O.K, Darryl....can we agree that...manufacturers are moving in a forward direction when directly applying their highest quality progressive design (to a production mold) via freeform equipment and/or optimizing full customization through a true freeform generated lens beginning from scratch (SV semi-finished blank) resulting in a better final product, again, derived from its highest quality design...I would be the first to agree that the quality of design will dictate ease in adaptation no matter which process is chosen...a poor design will just be a better poor design given advanced production methods....
For some reason, your company (and others) chose to move forward in developing advanced designs combined with advanced production methods. I would like to believe it is more than just the "marketing hype" shared by many viewers posting in these progressive discussions.....

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## Darryl Meister

Those are all very good points to make. I'll add that even free-form manufacturing has improved quite a bit over the last few years, as newer machines are able to achieve smoother surfaces that require less polishing (an operation that can potentially alter and distort the surface).

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## AustinEyewear

Wow - Great thread from the way-back machine.  Reading thru this thread now has me wondering if there is (still) a patent on back-side free-form progressives?  Its seems there are many manufactures using this technique now, so it would seem they have all come to terms or the patents have expired or something?  Anyone have clarity on this?

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## Judy Canty

For lack of a better word, the designs are "leased" on a per use ("click fee") basis from the lens manufacturers/designers.

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## AustinEyewear

> For lack of a better word, the designs are "leased" on a per use ("click fee") basis from the lens manufacturers/designers.


Are they paying royalties to someone?  Who is that entity?

I thought about this a little more, and realized my question may not have been specific enough.  What I am asking is not about the freeform software itself, I'm asking about the ability to utilize a backside progressive surface.  From reading thru some of these posts, it appears that this what would seem simple enough issue, is patented, forcing others to ether place the progressive surface on the front, or pay royalties for the privledge of placing it on the back (even though they develped their own free form software that will creat the point files to generate the surface using a CNC machine).  Is this the situation?  Does my question make sense?

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## Judy Canty

There are a very small handful of lens designers in this industry, and it's not all that easy to develop, test and then market new lens designs.  So this handful works for whomever signs their checks.  The designs are available, as I said via a "click fee" or a "royalty".  Anyone with the capabilities can put a design on any surface, but they've got to get the design from someone. Some manufacturers who seem to introduce new designs at an alarmimg and often confusing rate may actually be "tweaking" an existing design and re-introducing it.  It's that "new and improved" designator we see so often in the grocery aisles.  If your rep can't explain the differences in understandable terms, not marketing jargon, then perhaps it's not really new or improved.

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## AustinEyewear

> There are a very small handful of lens  designers in this industry, and it's not all that easy to develop, test  and then market new lens designs.  So this handful works for whomever  signs their checks.  The designs are available, as I said via a "click  fee" or a "royalty".  Anyone with the capabilities can put a design on  any surface, but they've got to get the design from someone. Some  manufacturers who seem to introduce new designs at an alarmimg and often  confusing rate may actually be "tweaking" an existing design and  re-introducing it.  It's that "new and improved" designator we see so  often in the grocery aisles.  If your rep can't explain the differences  in understandable terms, not marketing jargon, then perhaps it's not  really new or improved.


Sorry, not sure if I was clear.  I was referring to the comments below. I'm wondering if the big boys who do have the ability and financial resources to design the software have to pay royalties to put their designs on the backside because someone holds a patent to put the PAL surface on backside?  (yes, I do understand the designs evolve and are licensed)





> The first US Patent issued covering this issue is  US Patent 6,019,470.
> 
> This Patent issue is real and I would not recommend selling lenses produced with a backside PAL unless these are manufactured outside of the US.
> 
> This Patent is not licensed to Shamir for the Autograph as I understand.
> 
> I would like to thank Laurie for the confirmation of my belief.  I do not understand why Shamir is currently attempting to have their partner labs produce these backside PAL lenses without the assignment of the rights to do so.  It is my understanding that Shamir does not have such rights. 
> This is a new area for optical lens production and is quite different from other PAL designs in the ability to produce very customized lenses.





> Laurie;
> 
> 
> In the above you state that Shamir may very well hold the patent.  Which they certainly do not hold the original patent for backside progressive maintaining a spherical front surface.
> 
> 
> 
> I await your findings.  In another thread someone else reports this patent issue has been resolved.  I have not been able to confirm this resolution.  I would think if Shamir does have a clearly defined resolution that the information would be available.





> It is my understanding that there are overlapping patents issued covering the technique of spherical front/PAL back. One is owned by Seiko-Epson, the other is owned by Carl Zeiss Vision. Seiko-Epson has given lens companies such as Shamir the right to use this technique, for a small fee, _<wholesale pricing removed>_. Unfortunately, CZV has not. This issue remains unresolved and is currently the biggest obstacle to this technology coming to market.

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