# Optical Forums > Progressive Lens Discussion Forum >  Auto III/Physio Enhanced

## scriptfiller

Do they play in the same league/ball park?  Thanks for any enlightening comments.

----------


## merrymaker

Well...if we're looking at VSP categories....the Auto III would be in the same category as Physio Enhanced *Fit* and/or Varilux S Series Fit.

The Auto III is a much newer product than the Physio Enhanced so keep that in mind (doesn't use POW measurements.) My Shamir rep was just in this morning so the tech details of the Auto III are still fresh and I would say that Enhanced is years behind the tech in the Auto III.

----------


## Boldt

I agree about the levels of tech between the two. 
From what I understand the Physio Enhanced is a digital lens wile the Auto 3 is a free form. The biggest difference is that the Auto 3 has a design specifically for myopes and hyperopes. 
As for what I've seen from them, I've had no real non-adapts (one just refused to give getting used to a pal time) with the Auto 3 and I've been using it for almost a year. They Physio Enhanced I've had a few over the years I used it. Mostly myopes that did not like the reading areas or where taken out of a Seko or Shamir design. The only down side to the Auto 3 is the price. Almost double what the auto 2 is.

----------


## FL-Opt

I agree. The Auto III technology is far more advanced and more customizable than the Physio 360 Enhanced. If I'm not mistaken, I believe that the Auto III is a fully back surface design and the Physio 360 enhanced is a dual surface (front & back) design. I have heard most people say that they've had less "non-adapts" from Auto III than from Physio 360 enhanced.

----------


## Jamcar97

[QUOTE=Boldt;490246]I agree about the levels of tech between the two. 
"From what I understand the Physio Enhanced is a digital lens wile the Auto 3 is a free form."

"Digital" and "freeform" are one and the same. Not a lens but a process.

----------


## golfnut

[QUOTE=Jamcar97:490259]


> I agree about the levels of tech between the two. 
> "From what I understand the Physio Enhanced is a digital lens wile the Auto 3 is a free form."
> 
> "Digital" and "freeform" are one and the same. Not a lens but a process.


Actually "digital" is the process and "freeform" is the design. So they are not the same.

----------


## Robert Martellaro

Digital =  data stored and processed using numerical strings of 0's and 1's, using machine and programing languages, dacs, and computers.

Free-form = a surface, made by a machine/manufacturing platform that can generate and polish non-rotationaly symmetric surfaces.

If you want to separate the men from the boys, use the terms customizable and optimized, and be specific.

----------


## ThatOneGuy

[QUOTE=golfnut;490263]


> Actually "digital" is the process and "freeform" is the design. So they are not the same.


Actually, you're both wrong.

Digital lenses are merely typical molded lenses like have been around forever, except they skip one step in the manufacturing of the lens because that step has been digitized.  It's like the paperless office of progressive lenses; they help maintain more consistent quality of molded lenses, so there are fewer defective products.

Freeform lenses in and of themselves are hardly any better.  All a freeform lens does is use a generator that is capable of complex cuts.  This can be applied to an existing molded design, or a customized product can be produced from it.

The Auto III is a freeform lens that ALSO incorporates additional algorithms to improve the performance of the lens design for a given rx

The Physio Enhanced is also freeform, based on the physio design, that then makes modifications to the design to improve the performance for a given rx.

----------


## Uncle Fester

> Digital =  data stored and processed using numerical strings of 0's and 1's, using machine and programing languages, dacs, and computers.
> 
> Free-form = a surface, made by a machine/manufacturing platform that can generate and polish non-rotationally symmetric surfaces.
> 
> If you want to separate the men from the boys, use the terms customizable and optimized, and be specific.


Am I the only one who reads this OP and find myself scrolling down to see if Mr. Martellaro has chimed in?   :Smile: 

strings of O's and 1's--- point files?

dacs--- Data Acquisition and Control?

Non-rotationally symmetric surface--- Using a cutting tool rather than a lap?

Welcome to Optiboard and your baptism by fire Jamcar97! We all experience it!!! Keep posting. :Smile:

----------


## TLG

> Do they play in the same league/ball park?


No. Physio has the PAL design molded onto the front with the backside being freeform generated. The Auto3 is a full-backside freeform which means the PAL design, Rx and any customization/optimization all occur on the backside of the lens. There is a huge difference.
I don't have much experience with Essilor lenses but my understanding is that the "Short" version of Physio uses the same blank as the standard, but is then digitally customized on the back to create the short corridor effect.

----------


## optical24/7

Physio Enhanced does not qualify as a "Freeform lens" because it has a molded front/PAL design ( Same blank as a regular Physio) with digital enhancement applied on the back (atoricity/asphericity).

 "Digital" is a manufacturing platform, just like a regular generator is a platform of manufacturing. Just because a lens is run on digital CNC equipment does not make it freeform. You can run a regular FT 28 on digital equipment, add atoricity/asphericity optimization, but it's still not a "FF" lens since it used regular molding technology on the front.

----------


## ThatOneGuy

> Physio Enhanced does not qualify as a "Freeform lens" because it has a molded front/PAL design ( Same blank as a regular Physio) with digital enhancement applied on the back (atoricity/asphericity).


+1

I think I'm thinking of Physio Drx that is the back side "freeform," which is more or less a physio enhanced but full back surfaced.

Full disclosure:  I don't use essilor/varilux progressive products unless absolutely necessary and haven't for years, so I only know enough about the products to know that I'm still not impressed (although they are working on it).

----------


## Robert Martellaro

[QUOTE=Jamcar97;490259]


> "Digital" and "freeform" are one and the same.


True, in the sense that that they convey no information about the quality of the optics. Similar to 'HD' lenses.  




> strings of O's and 1's--- point files?


Point files are the data files that describe surfaces, in the form of digital, that is, 0's and 1's. I'm only a dispensing optician, so to go further, let's call in an expert in modern ophthalmic lens manufacturing. 




> dacs--- Data Acquisition and Control?


Digital to analog conversion.




> Non-rotationally symmetric surface--- Using a cutting tool rather than a lap?


An atoric surface.

----------


## scriptfiller

Nice discussion on processing nuance, informative.

Using the "fixed" corridor "model" of the Auto III, does that give me the ability to custom tailor a fitting for my patients?  For instance using a shorter corridor model to emphasize reading area and vice versa use a longer corridor model to emphasize intermediate.  This is not available to me in the Physio Enhanced?

Am I correct in reading the literature on the Auto III that they employ an optical design that gives the same angular field of view regardless if the RX is myopic or hyperopic?

Thanks

----------


## merrymaker

> Nice discussion on processing nuance, informative.
> 
> 
> Am I correct in reading the literature on the Auto III that they employ an optical design that gives the same angular field of view regardless if the RX is myopic or hyperopic?
> 
> Thanks


Yes you are correct.

----------


## Joyley

I'm still lost.   I've been told that Definity (Essilor) was the first dual sided digital lens.  Then there are lenses which are all back side, not split.
So, baby stepping backwards, dual split or back side only?  Which is better. 
After that, I need to figure out which is the best lens for us. I'm leaning toward the Auto III, although some of our opticians would  say the Physio 360.  (((  By the way, what is the difference between the Physio Enhanced and the Physio 360???)))

----------


## merrymaker

The Physio 360 has been discontinued, no?

----------


## Jason H

The bias against Essilor is what it is - and much of it deserved. But the Enhanced line does have some advantages for hyperopic patients. To keep the plus power (at least in the bifocal) on the front surface is a cosmetic advantage and simplifies digital grinding on the back surface. Physio and Comfort are proven designs. Autograph 3 seems to be a much improved design over the Auto 2 for plus powers - especially for reading convergence. I don't have a problem reccomending either.

----------


## Robert Martellaro

> I'm still lost.   I've been told that Definity (Essilor) was the first dual sided digital lens.  Then there are lenses which are all back side, not split.
> So, baby stepping backwards, dual split or back side only?  Which is better. 
> After that, I need to figure out which is the best lens for us. I'm leaning toward the Auto III, although some of our opticians would  say the Physio 360.  (((  By the way, what is the difference between the Physio Enhanced and the Physio 360???)))


Adding to Jason's post-

In general, a split add is not inherently better, but putting some or all of the add on the front for moderately high and high plus RXs allows a flatter base curve (reduced magnification and better cosmesis), encouraging a steeper (non-negative or plano) ocular curve.

----------


## Sphinxsmith

SharpStick has posted some quality info on much of these topics in his recent posts. I went back and re-read a bunch of them not long ago, wealth of information. 

CS

----------


## stedel

Here's my understanding of what Essilor calls "digital", gained directly from an Essilor lab person:

*1)* Older (mostly no longer sold) Conventional Essilor Progressive: A lens where the front basecurve of the lens isn't uniform all the way across the lens. Instead, it curves at a varied rate, effectively adding power toward the bottom of the lens. The front side of the lens is molded, and the back side is surfaced.

*2)* Newer Conventional Progressives (original Comfort and newer): Similar to the original progressives, except each add power has its mold individually optimized for that add power, rather than using a general design for all add powers. Conventional backsurfaced lenses.

*3)* "Digital" Progressives (Ovation DS): Basically identical to the newer Essilor Conventional Progressives (they use the same conventional molds, in fact), except they use  funky computer software during their standard back surfacing to optimize  the lens slightly more for the particular frame, heights, and PDs. This helps give a better product, and it helps more than you'd think likely. Ovation DS is a decent step up from Conventional Ovation, despite using the same blanks.
*
4)* Advanced Digital Progressives: Uses the same software enhancements during surfacing as their digital progressive lenses. In addition, the lens molds are  designed using more advanced computer modeling techniques, giving a more  refined end result. To reiterate, these are **new lens molds**, and thus yield a very different (especially from the customer's point of view) product than their standard digital counterpars. Ovation ADS (Advanced Digital Surfacing) and many other "enhanced" lenses fall under this category. This category includes what Essilor calls "DDV technology", and according to the lab guy, "DDV gives "Point by Point" accuracy or what we called Image Control".

None of those products uses anything that could be described as a "freeform" process. 

That's what the Essilor lab guy I talked to said. Can't say for sure how much of it is correct, but it certainly fit with what I knew.

It's my understanding (and this is partly just guesswork on my part), that a Physio DS is a standard "Digital" product that uses a conventional Physio blank, while a Physio 360 uses the ADS system, and significantly decreases the downsides of the Physio/PhysioDS line of products. The Comfort and Physio 360 are quite different products from a customer point of view when compared to their conventional and older digital counterparts though, and customers occasionally have difficulty adapting, in my experience. Especially comfort. I find that a switch from Comfort to Comfort 360 doesn't work as well as Comfort to Ovation ADS, strangely. Wouldn't think it would work that way.

----------


## iD

Every Physio Enhanced that I've put a patient in has come back unhappy. For some reason it's not a big hit over here. Auto III I haven't had one complaint...yet.

----------


## eyepod

It's nice to see someone get it right, as far as digital vs. freeform.  Freeform is a process.  Digital lenses can still be molded, and the molds can also be produced digitally.  As far as split add power, I do not see the benefit.  When the design and power are on the back surface, patients perceive them as being wider. (The old keyhole effect).  Additionally, with split adds, if lenses aren't blocked correctly or they slip, what you just surfaced on the back does not line up with what is molded on the front.  this is extremely hard for the average optician to detect.

----------


## Happylady

> Every Physio Enhanced that I've put a patient in has come back unhappy. For some reason it's not a big hit over here. Auto III I haven't had one complaint...yet.


 Interesting. We use Physio, Physio Short and Physio Enhanced all the time with no issues. One thing I find important with them is that they are fit on the pupil and not dropped.

----------


## eyepod

Auto 3 does use POW measurements. Shamir requests vertex, wrap and tilt.  





> Well...if we're looking at VSP categories....the Auto III would be in the same category as Physio Enhanced *Fit* and/or Varilux S Series Fit.
> 
> The Auto III is a much newer product than the Physio Enhanced so keep that in mind (doesn't use POW measurements.) My Shamir rep was just in this morning so the tech details of the Auto III are still fresh and I would say that Enhanced is years behind the tech in the Auto III.

----------


## iD

> Interesting. We use Physio, Physio Short and Physio Enhanced all the time with no issues. One thing I find important with them is that they are fit on the pupil and not dropped.


We use the Physio here and no one has complained about that one. The Physio Enhanced does poorly here for some reason and any measurement is never dropped. That confuses me still.

----------


## scriptfiller

We are going to give the Auto III a whirl and see how it does for us.  Thanks for the discussion

----------


## WFruit

Some wise person on this board once wrote "All Free Form lenses are Digital, but not all Digital lenses are Free Form." And no, that person wasn't me.

So, here are the different manufacturing processes, regardless of what you want to call them, as seen from someone who works in a lab that does most of them:

Front side molded conventional progressive, digitally optimized back surface.  Examples:  Hoya iQ series, Essilor 360 and Enhanced series

Front side molded progressive design, with partial add power, digital back surface with remainder of the add power.  Example:  Essilor Definity

Front side molded vertical portion of progressive design, digitally surfaced horizontal portion of progressive design.  Examples:  Hoya iD LifeStyle, Hoya iD Lifestyle 2

Spherical front surface lens, digitally surfaced Free Form progressive design back surface.  Examples:  All Shamir FreeForm designs, All Seiko Free Form designs, All IOT Free Form designs, Hoya Array

Digitally surfaced front AND back surface.  Examples:  Hoya MyStyle, Hoya InStyle

Now, since we don't run Zeiss in house, I have the least amount of knowledge of their lenses.  Can someone please educate me on where their lenses would fall in the above categories?

----------


## Robert Martellaro

> Now, since we don't run Zeiss in house, I have the least amount of knowledge of their lenses.  Can someone please educate me on where their lenses would fall in the above categories?


Spherical front, back progressive for all but high plus, where both surfaces are worked. It seems likely that the front has the progressive optics, with a spherical/toric or atoric back for the high plus, up to +16.00 D.

----------


## stedel

> Spherical front, back progressive for all but high plus, where both surfaces are worked. It seems likely that the front has the progressive optics, with a spherical/toric or atoric back for the high plus, up to +16.00 D.


I've been told that a spherical front, backside progressive is functionally identical to a progressive where both sides are surfaced for everything but moderate to high plus powers. Is this true?

----------


## Judy Canty

Pretty much.

----------


## ThatOneGuy

> Some wise person on this board once wrote "All Free Form lenses are Digital, but not all Digital lenses are Free Form." And no, that person wasn't me.
> 
> So, here are the different manufacturing processes, regardless of what you want to call them, as seen from someone who works in a lab that does most of them:
> 
> Front side molded conventional progressive, digitally optimized back surface.  Examples:  Hoya iQ series, Essilor 360 and Enhanced series
> 
> Front side molded progressive design, with partial add power, digital back surface with remainder of the add power.  Example:  Essilor Definity
> 
> Front side molded vertical portion of progressive design, digitally surfaced horizontal portion of progressive design.  Examples:  Hoya iD LifeStyle, Hoya iD Lifestyle 2
> ...


GT23D is aspherical front surface with full backside free form surfacing.
Individual 2  is aspherical front surface with full backside free form surfacing.

The difference is in what design is placed on the lens.  A GT23D places a GT2 design on the back surface, with compensated curvatures to enhance the performance of the design with a given Rx (So it attempts to eliminate unwanted astigmatism caused by the given rx where the given rx might not be ideal for the given design/BC/etc).

An Individual 2 has target performance goals in the various zones of vision that are regulated by a math formula.  By supplying the rx, frame size/shape, position of wear measurements, etc., the formula is able to specify more exact curvatures necessary to meet the target performance of the lens.

Edit:  Individual 2 1.74 is dual surface free form

----------


## Robert Martellaro

> GT23D is aspherical front surface with full backside free form surfacing.
> Individual 2  is aspherical front surface with full backside free form surfacing.


When did they change to an aspheric front? Zeiss owns the free-world patent (USPTO 6,089,713) on multifocal back side lenses with a spherical rotationally symmetrical front surface!

----------


## sharpstick777

Things that make me go Hmmmm.

You have never worked in a Free-form lab have you?




> Actually, you're both wrong.
> 
> Digital lenses are merely typical molded lenses like have been around forever, except they skip one step in the manufacturing of the lens because that step has been digitized.  It's like the paperless office of progressive lenses; they help maintain more consistent quality of molded lenses, so there are fewer defective products.
> 
> Freeform lenses in and of themselves are hardly any better.  All a freeform lens does is use a generator that is capable of complex cuts.  This can be applied to an existing molded design, or a customized product can be produced from it.
> 
> The Auto III is a freeform lens that ALSO incorporates additional algorithms to improve the performance of the lens design for a given rx
> 
> The Physio Enhanced is also freeform, based on the physio design, that then makes modifications to the design to improve the performance for a given rx.

----------


## sharpstick777

> Edit:  Individual 2 1.74 is dual surface free form


Only in powers greater than a +6.00 and made in Germany, its single surface free-form otherwise.

----------


## sharpstick777

From Bruce at Optivision:


LDS = Lens Design System, or Lens Design Software, the lens vendor's   proprietary custom freeform lens design software.SDF = Surface Definition File, or Surface Data File, a three-point file of   the X, Y, and Z coordinates that describe the surface height across the lens   surface, like a 3D picture of the surface, commonly referred to as a points    file.
LMS = Lab Management System, or Lab Management Software, the lab software   used at the optical lab.

The typical freeform process:

*1)* An Rx order is entered into the LMS Lab Software.

*2)* The Lab Management System generates and sends an ".LDS"  file, which has all of the required Rx job info, to the lens vendor's custom  freeform software.

*3)* From the patient’s Rx, center & edge thicknesses,  and other details in the ".LDS" file, the lens vendor's custom freeform software  calculates the freeform Rx, generates an ".SDF" file which is sent to a  designated storage area, such as a server, that can be accessed by the LMS and  the blocker, generator, polish, and laser engraver machines.

*4)* The lens vendor's custom freeform software generates  and sends an ".LMS" file, which has the  location of the storage area and  the Rx details, to the Lab Management System.

*5)* When requested by the freeform machines, the LMS sends  the data location and any other info required to the relevant machines to access  the data and undertake its function in the lens production process.


Hope this explains some of  this better. 
Cheers,

~ Bruce

Bruce Krymow 
Director, Marketing & Operations 
Optivision®,  Inc.

----------


## sharpstick777

> When did they change to an aspheric front? Zeiss owns the free-world patent (USPTO 6,089,713) on multifocal back side lenses with a spherical (rotationally symmetrical) front surface!


Robert, the orginal GT3D was for a short time a hybrid lens like the enhanced with the add on the front with the traditional GT3D blank, I don't know if was released in all markets (I only saw the marketing material).  A short time later it was a fully Free-form backside add lens.  I don't know when it switched, or if it was just misprinted marketing material.  But it is the source for the confusion I assume.  Technically a standard progressive blank is aspheric.

----------


## sharpstick777

The major difference between the Auto III and the Physio Enhanced is that the Add (most of it) remains cast on the Physio Enhanced.  The effect of this cannot be overstated.  I am convinced the only reason that manufactures started and continued this "hybrid" digital back and cast front lens design is to avoid paying patents to Seiko and Zeiss who own the 2 patents necessary for free-form. 

The optical difference are huge, because we don't truly have ANY Front side add lens (relative to the sphere power).  All Progressives have a back side add as it sits in a plane behind the distance spherical power.  The difference however is that the smooth transitional curves that join the distance and reading surfaces are on either the front or the back, or both.  But on the front combined with the displacement of the add, the effect is huge.

yes, you can conceivable have a so called "frontside" add lens where the add power is technically behind a so called "backside" all lens.  The impact on this optically is enormous.  Because when the transition curves (or add power for you not catching up) is on the front, it must resolve smoothly with the spherical surfucae it NEVER intersects.  The consequence of that is I will always have 2 opposite direction transitional curves.

With the add on the back however (really the transitional curves on the back) the add power is the flattest portion of the lens, and the effective spherical power is the steepest, but more importantly the plane of those curves intersect.  That means I only need one transitional curve to link those two surfaces smoothly.  The net result is wider fields of view, and less unwanted prism (swim or sway).

The mixed or hybrid lenses with the add (or a portion of the add) on the front end up with 3 transitional curves, 2 on the front, 1 on the back.  Aligning those 3 curves precisely (although possible) is currently beyond any current blocking technology even in spherical powers.  Cyl just makes that whole conversation and math exponentially messy, it would take a day or 2 to calculate even if we could block it out perfectly.   

The above is easiest to explain when dealing with the potential number of possible focal points.  In minus power a backside add (and transitional curve lens) will have a narrower range or cross section of possible focal points.  In plus powers that number drops for various reasons, but backside transition curves hold less of an advantage in my math up to +6.00, then a front side add lens gains some traction (it has to do with how base curves are calculated in free-form vs traditional lenses).  Interestingly that is where Zeiss starts moving the add to the front of the Individual 2. 

So we have a few different category of lenses.  I would NOT trust Essilors definition:

Digital Lenses:  Processed on CNC lathe, but offer no compensated curves or backside transitional curves
Hybrid Lenses:  Digital processed on back, some add on front.  The add power or Location is not fully optimized.  Usually distance power only on the back that might receive basic aspheric compensation (Read Essilor Physio Enhanced).
Free-form Lenses:  Simple:  Only basic compensations for base curve and cyl, but the add is all on the back
Free-form Lenses:  Advanced:  More advance compensations based on averages of panto, face form and tilt, but not optimized individually.  may or may not include frame data.
Free-form Lenses:  Advanced or Personalized.  Similar to and advanced lens but taking the POW measurments for each person, add fully on the back. (Think Autograph III).

So the Auto III is technically many levels superior to the Physio Enhanced.

----------


## sharpstick777

The best example highlighting the difference between various classes of 100% pure free-form lenses is:

Shamir
Element:  Basic Free-form, not unlike a SV aspheric lenses, but with the add on the back. Compensations for base curve and atoricity based on a 0 fitting.
Spectrum:  Fully compensated powers, distance and near, but based on averages for vertex, panto and tilt.
Autograph II & III:  Individually compensated, based on individually measured vertex, panto and tilt

----------


## sharpstick777

Hybrid lenses (with the Add cast the front and partly Free-form the back) suffer in a few ways.  The greatest of which is that I have 3 transitional curves, 2 on the front and 1 on the back that I have to align for optimal optics.   this gets tricky because I have to de-block a lens to surface both sides, or depend on the accuracy of the casting (which is very messy at best).  Neither is an good choice.  

These transitional curves all have differing angles, and those angles will vary depending on the cyl and add powers involved.  So they can be a mess directionally, and greater unpredictability esp in peripheral vision as we move farther from the center. 

So although using a dual surface design has some possibilities, aligning 3 curves with varying angles and powers of unwanted cyl that change with each effective correctives cyl creates a mathematical nightmare.  And even if I could fix that, the blocking we use today would mess it all up anyway.  

This is why Zeiss and Seiko have stayed away (mostly) from 2 surface designs, Shamir paid their patent fees at the beginning, and you find the only ones to make hybrid lenses are also the only ones to reach financial terms with Seiko and Zeiss after many many years of holding out.

----------


## merrymaker

*mind blown*

----------


## stedel

Thanks sharpstick, that was helpful. Somewhat separately, does anyone know exactly where Zeiss's Choice lens series sit?

----------


## scriptfiller

Thanks sharpstick, most informative series of posts concerning the original topic.  Hat's off to ya!

----------


## Robert Martellaro

> Robert, the orginal GT3D was for a short time a hybrid lens like the enhanced with the add on the front with the traditional GT3D blank, I don't know if was released in all markets (I only saw the marketing material).  A short time later it was a fully Free-form backside add lens.  I don't know when it switched, or if it was just misprinted marketing material.  But it is the source for the confusion I assume.  Technically a standard progressive blank is aspheric.


It was a rhetorical question. They use spherical SFSV blanks.

I think everyone is getting too hung-up on the progressive optics placement, whether it's molded or direct surfaced, etc. What matters is reduced aberrations, the fundamental PAL design, understanding the differences in design, how the design and functionality adheres to the intended design over a wide range of RXs and fitting parameters, and matching that design to the clients visual needs.

----------


## sharpstick777

Zeiss's Choice sits next to Spectrum.  The Choice Plus, and Choice Plus V are almost between the Spectrum and Autograph series because of the greater corridor options.

----------


## stedel

> I think everyone is getting too hung-up on the progressive optics placement, whether it's molded or direct surfaced, etc. What matters is reduced aberrations, the fundamental PAL design, understanding the differences in design, how the design and functionality adheres to the intended design over a wide range of RXs and fitting parameters, and matching that design to the clients visual needs.


I can't speak for everyone else, but understanding how each lens functions in reality is exactly what I'm trying to do. Unfortunately there doesn't seem to be a third party research group (or even a half-assed group like Consumer Reports) that checks these things out. All I (and, I assume, others) have to go on is absurd hype from each manufacturer, and (often unreliable, at best weakly anecdotal) patient feedback.

I want a straight up, "this lens will work this way for these people" for each type of lens. I want them ranked. I want them categorized. I want them thoroughly tested. And I want all that done in a scientifically rigorous fashion, by unbiased third parties. I don't want any of this "well, it's more of an art..." crap, I want hard science.

But that clearly doesn't exist, mostly because no one cares enough to spend the time, effort, and money necessary to do it. Which is crazy, given how important a field this is. I mean, can you imagine the FDA just saying "ah well, just let that new artificial heart out on the market. I mean, sure it hasn't been rigorously tested, and all we have to go on are claims by a shady company's marketing department, but meh". People's lives depend on their eyes, but it's like no one important really cares. Heck, MY LIFE depends on the eyes of other people while they drive their vehicles.

/rant

Anyway, that's the reason why I'm here, at least. If I can't access any real research on lenses, then I have to settle for anecdotes. And if I'm going to settle for anecdotes, I want it to be anecdotal evidence from the most experienced people I can find. Which is all of you, here. It's unacceptable that I (and others) have to go to these lengths just to learn basic information about lenses, but that seems to be the way it is right now.

----------


## Robert Martellaro

> I want a straight up, "this lens will work this way for these people" for each type of lens. I want them ranked. I want them categorized. I want them thoroughly tested. And I want all that done in a scientifically rigorous fashion, by unbiased third parties. I don't want any of this "well, it's more of an art..." crap, I want hard science.


This should help.

http://www.youngeroptics.com.br/arqu...ient_needs.pdf

We can perform our own subjective testing also.

************************************************************  ****************

A realistic assessment of FF PALs.

http://www.iot.es/ffadvantages.html

Some highlights...

*What is Free Form (FF)?*
 Free form is a manufacturing technology that allows cutting and polishing arbitrary surfaces
 A lens is free-form if
- At least one of its surfaces is made with free form technology and
- That surface is not spherical neither torical
*What cannot be done with advanced ophthalmic design and FF technology?*
 Progressive lenses that violates Minkwitzs theorem (PALs with wider corridors for the same corridor length.)
 Lenses without aberrations
 Lenses which compensates for third order eye aberrations at any direction of sight (those can be compensated only within a very narrow field)
 PALs without adaptation period.
 Short PALs with intermediate wide enough for computer displays.
*Back-side or front-side?*
 The position of the progressive surface (even if there are two progressive surfaces) is not that important.
 The important thing is the progressive surface (or both) being free-form and computed with good software, not the position.
 The performance of any front side PAL can be reproduced in a back side PAL. The opposite is also true.
 Some miss-conceptions about back-side progressives:
 Field is wider because the surface is nearer to the eye. Indeed the back surface is a little bit nearer, but also there is less room for progression on the back, so there is not net improvement.
 Magnification is more stable because front refractive power is constant. Thats true, but the effect is so small. Magnification is mainly due to power. As power increases in a PAL, so does magnification.
 Back side PALs produces less distortion. False. Distortion depends on the power variation. The faster the variation, the larger the distortion. This is a characteristic of the design, whether it is back of front.

----------


## Jason H

Great thread- thanks especially Robert and Sharpstick.

----------


## Jason H

I had always wondered how the corridors on the Enhanced series could narrow vertically if they are using the same molded blanks as Comfort and Physio with longer minimum seg heights. Any takers?

----------


## Jason H

[QUOTE=sharpstick777;493790]T

The optical difference are huge, because we don't truly have ANY Front side add lens (relative to the sphere power).  All Progressives have a back side add as it sits in a plane behind the distance spherical power.

----------


## Jason H

Are you speaking of pantoscopic angle bringing the add power closer to the eye here?

----------


## Jason H

Sorry, bad at computers.

----------


## Robert Martellaro

> I had always wondered how the corridors on the Enhanced series could narrow vertically if they are using the same molded blanks as Comfort and Physio with longer minimum seg heights. Any takers?


Because the backside is produced on a free-form generator, they can modify the progressive optics as needed, with the appropriate software of course. The Physio Short for example, in Trivex, starts out with a regular semifinished Physio blank. The manufacturing complexity is higher, but inventory cost is lower. 

This could then technically be called a free-form lens, although it's probably lacking any additional optimizations compared to what could have been an off-the-shelve semifinished PAL. But the Physio Enhanced is absolutely and without any doubt a free-form lens with optimizations.

----------


## sharpstick777

> Are you speaking of pantoscopic angle bringing the add power closer to the eye here?


No, the umbilic of a "front side" progressive must always offer increasing plus powers, so from the distance reference point it must turn "in" closer to the wearer.  The add of "front-side" add lenses will always sit behind, not in front of, the distance spherical power.   If it stuck in front even for a tiny bit it would render some portion of the corridor unusable, it would be over minused.

----------


## sharpstick777

> .
> 
> http://www.youngeroptics.com.br/arqu...ient_needs.pdf
> 
> *Back-side or front-side?*
> • The position of the progressive surface (even if there are two progressive surfaces) is not that important.
> • The important thing is the progressive surface (or both) being free-form and computed with good software, not the position.
> • The performance of any front side PAL can be reproduced in a back side PAL. The opposite is also true.
> • Some miss-conceptions about back-side progressives:
> ...


I will disagree with Younger here, the "backside add" (really backside transitional curves)  is extremely valuable because there is enormously more power variation outside of the corrective curves when the transition curves are on the front, vs. the back.  
Its not unlike Edward Tillyers work in the 1920's to prove Cylinder correction should be on the back, not the front of a lens.  Sadly most of what his work wasn't fully appreciated and implemented until the early 1970's.

Since the front side add sits behind the spherical curve, they never intersect on any plane.  To smoothly merge those curves ( a requirement of a progressive being "no-line") I will need two transitional curves to do so, one with high plus cyl and one in the reverse direction with high minus cyl. Its sort of an S shape from a cross section. When the transitional curves are on the back, the add is flattest portion of the lens and sphere power is always steeper.  The result is the Add power always intersects the plane of the sphere.  I only need one transitional curve.

the net result is that although both create distortion, the total number of focal points will be spread over a wider area than a single unwanted cylinder curve would be.  It will also require more "space" to resolve both curve smoothly.  Less range in focal points, equals less swim or sway.  Less space equals greater (wider) usable zones.  It creates its own base curve issues, so it necessarily doesn't cut the distortion in half (100% backside free-form lenses don't use Vogels rule for base curves, esp in plus powers). 

We always focus on the corrective curves, but the non-corrective curves have a huge influence over the lens.  

Here is the way to see it more simply.  

Here is the curve line of Traditional front lens:  
Convex curve for Distance,  
Steeper Convex curve for first transition curve (beginning of soft focus area, very high plus cyl
Steep Concave Curve to link the first Convex curve to the reading. (end soft focus area)
Steep Convex curve for the reading zone (usable)
Steep Concave Curve (unusable)
Steep Convex Curve (unusable)
Convex Curve (usable distance portion)

Backside 100% Free-form lens
Steep Concave Curve (for distance)
Flatter Concave curve (to link distance to reading, soft focus area, minus cyl only)
Flat Concave curve (usable reading area)
Flatter Concave curve (soft focus area, minus cyl only)
Steep concave curve (for usable distance zone)

The backside Free-form lens is ALL Concave surfaces, there is patent that ensure this for most lenses.

Mixing Convex and Concave surfaces on the front of a progressive (As in all traditional and hybrid lenses) creates far great variation in unwanted cyl and prism.  In a backside add lens, all the surfaces are concave, of varing degrees.  There is distortion, but the variance in unwanted focal points is far less.  Less swim or sway.  Voila.

Me thinks that Younger knows this, its what makes their newer Camber lens so intriguing, it does not have any concave surfaces on the front, its all convex.  Would Younger care to comment?

----------


## sharpstick777

The simplest way to visual is this, is that the 2 front transitional curves on "front side add" progressive will pull the path of light in 2 directions off center.  Combined they created their own unwanted prism that is also divergent from the visual axis. In a backside add lens, that transitional curve only pulls the light path in 1 direction.  Both create distortion, but they vary by the type, direction and degree.  

There will generally be more swim or sway in a front side add lens as that light is pulled off to a higher net variance between the plus and minus cyl.  The math is interesting on this.

----------


## shanbaum

> When did they change to an aspheric front? Zeiss owns the free-world patent (USPTO 6,089,713) on multifocal back side lenses with a spherical (rotationally symmetrical) front surface!


A single-vision aspheric blank _is_ rotationally symmetrical.  A plus-cylinder lens (for example) would not be.  

There's no such thing as a "free-world patent."  The '713 patent is a U.S. patent; there's a similar one in Australia, and a somewhat less-broad variant in Europe.

----------


## Robert Martellaro

> A single-vision aspheric blank _is_ rotationally symmetrical.  A plus-cylinder lens (for example) would not be.


Fixed. Thanks for the catch. I type faster than I think sometimes.




> There's no such thing as a "free-world patent."  The '713 patent is a U.S. patent; there's a similar one in Australia, and a somewhat less-broad variant in Europe.


I was (mostly) joking!

----------


## shanbaum

> Thanks for the catch. I type faster than I think sometimes.
> 
> I was (mostly) joking!



You shouldn't joke about patents.




OK, I was joking.

----------


## Robert Martellaro

> When did they change to an aspheric front? Zeiss owns the free-world patent (USPTO 6,089,713) on multifocal back side lenses with a spherical rotationally symmetrical front surface!





> A single-vision aspheric blank _is_ rotationally symmetrical.  A plus-cylinder lens (for example) would not be.


As is a SV spherical blank. I thought I got the nomenclature wrong, but I didn't, so I unfixed the fix. What am I missing?

----------


## shanbaum

I read your original comment thus: "Why would Zeiss switch to aspheric blanks when they have a patent on backside progressives using rotationally-symmetrical spherical ones," implying that backside progressives using aspheric blanks would be excluded from their patent because they're not rotationally symmetrical.

Sorry if I read that incorrectly, but that still looks like a reasonable interpretation to me.

----------


## Robert Martellaro

> I read your original comment thus: "Why would Zeiss switch to aspheric blanks when they have a patent on backside progressives using rotationally-symmetrical spherical ones," implying that backside progressives using aspheric blanks would be excluded from their patent because they're not rotationally symmetrical.
> 
> Sorry if I read that incorrectly, but that still looks like a reasonable interpretation to me.


For a patent attorney!

I just meant that they have the patent, the experience and knowhow, and why would they deviate from that.

----------


## sharpstick777

> For a patent attorney!
> I just meant that they have the patent, the experience and knowhow, and why would they deviate from that.


I had a piece of marketing material that implied they were using the original GT2 semi-finished front add blanks.  If that is true, then moving more of those blanks would provide some incentive.  When I finally got around to ordering the lens for myself the marketing had changed about 6 months later.  So I can't verify that the lens was ever a hybrid (full cast add on the front, digital back) or if the marketing material was simply wrong.  It was just implied.  

Sadly our source as Zeiss has passed away...

----------


## sharpstick777

The press releases from Germany regarding the GT2-3D launch never say its 100% backside Free-form.  The press releases for the GT2-3D-V however, do make that clear.  The GT2-3D-V touts in being 100% backside free-form.  It may be a marketing error, but there is no mention of Free-form in the orginal GT2-3D release.  


http://www.meditec.zeiss.com/C1256A7...2573CC004E9B6D

----------


## Tallboy

Dude. This thread has become fantastic.

----------


## stedel

I have another question about Choice Plus. Is it based on anything? Like the GT2-3D is, presumably, a GT2 design converted to be used on freeform generators with single vision lens blanks, but otherwise pretty similar to a GT2 (except less swim because the power is ground into the back of the lens?). Otherwise, why call it a GT2-3D? If it is mostly new design based on the GT, it should be a GT3. :P. So now transfer that line of reasoning over to the Choice line of lenses. Is Choice Plus just an Individual2 without customization features, with the option for set corridors? Or is it just a new version of a previous Zeiss design? Or is it something completely different than either of those options?

If that ramble makes it sound like I'm confused, it's because I am. The marketing material is most unhelpful in distinguishing WTF these lenses are, and on which patients they should be used. They basically just "good better best" them, but I can't believe that's how it really is. When should I use an Individual over a Choice Plus? Or vise versa?

And, speaking of Individuals, are digital (or freeform, if there is a difference in this case?) single vision lenses any better than conventional? I got a pair of Essilor 360 lenses, and beyond really liking the newest formulation of the Crizal Forte UV coating (they really fixed a lot of my crazing and glare issues last time they revamped it), I notice no difference. I'm a -8.00 -1.00 in my bad eye. I'd think if any myop should be noticing a difference, I should be. Should I try a Zeiss Individual single vision lens next time I get the chance, or will it make no real difference over a stock lens?

Thanks. Hopefully those questions made sense.

----------


## Robert Martellaro

> I have another question about Choice Plus. Is it based on anything? Like the GT2-3D is, presumably, a GT2 design converted to be used on freeform generators with single vision lens blanks, but otherwise pretty similar to a GT2 (except less swim because the power is ground into the back of the lens?). Otherwise, why call it a GT2-3D? If it is mostly new design based on the GT, it should be a GT3. :P. So now transfer that line of reasoning over to the Choice line of lenses. Is Choice Plus just an Individual2 without customization features, with the option for set corridors? Or is it just a new version of a previous Zeiss design? Or is it something completely different than either of those options?
> 
> If that ramble makes it sound like I'm confused, it's because I am. The marketing material is most unhelpful in distinguishing WTF these lenses are, and on which patients they should be used. They basically just "good better best" them, but I can't believe that's how it really is. When should I use an Individual over a Choice Plus? Or vise versa?
> 
> And, speaking of Individuals, are digital (or freeform, if there is a difference in this case?) single vision lenses any better than conventional? I got a pair of Essilor 360 lenses, and beyond really liking the newest formulation of the Crizal Forte UV coating (they really fixed a lot of my crazing and glare issues last time they revamped it), I notice no difference. I'm a -8.00 -1.00 in my bad eye. I'd think if any myop should be noticing a difference, I should be. Should I try a Zeiss Individual single vision lens next time I get the chance, or will it make no real difference over a stock lens?
> 
> Thanks. Hopefully those questions made sense.


http://www.optiboard.com/forums/show...l=1#post456317




> Should I try a Zeiss Individual single vision lens next time I get the chance, or will it make no real difference over a stock lens?


The answer is complicated. Individual sensitivities vary significantly for one thing. 

At this power, a premium stock SV finished lens can perform very well and may be hard to beat. Semifinished aspheric lenses, especially in the higher refractive indexes, may suffer from a lack of base curves compared to spherical blanks. We won't use a spherical blank with a power of -8.50 because the best form BC of 1.74 is a rather steep +4.25, increasing thickness, weight, and sag depth, potentially introducing noticeable aberrations off-axis, primarily oblique astigmatism. If the software compensates for tilt, there can be improvement in vision on-axis as well as off-axis, especially when the tilt values are greater than about five degrees.

For example, with your Rx (axis 180) the client chooses a frame that results in a pantoscopic tilt of 12 degrees, and can not be reduced to a lower value due to the endpiece design. Wrap is a typical five degrees. The compensated Rx is about -7.75 -.62 x 16. Without the compensation, the client will be over-minused, with incorrect cylinder and axis values. An emerging presbyope will be most unhappy!

With the cost of optimized free-form lenses decreasing, approaching the cost of semifinished, it makes sense to take advantage of this technology. However, make sure that your clients have been provided with realistic expectations when the expected improvement in optics is small.

----------


## sharpstick777

> http://www.optiboard.com/forums/show...l=1#post456317
> 
> The answer is complicated. Individual sensitivities vary significantly for one thing. 
> 
> At this power, a premium stock SV finished lens can perform very well and may be hard to beat. Semifinished aspheric lenses, especially in the higher refractive indexes, may suffer from a lack of base curves compared to spherical blanks. We won't use a spherical blank with a power of -8.50 because the best form BC of 1.74 is a rather steep +4.25, increasing thickness, weight, and sag depth, potentially introducing noticeable aberrations off-axis, primarily oblique astigmatism. If the software compensates for tilt, there can be improvement in vision on-axis as well as off-axis, especially when the tilt values are greater than about five degrees.
> 
> For example, with your Rx (axis 180) the client chooses a frame that results in a pantoscopic tilt of 12 degrees, and can not be reduced to a lower value due to the endpiece design. Wrap is a typical five degrees. The compensated Rx is about -7.75 -.62 x 16. Without the compensation, the client will be over-minused, with incorrect cylinder and axis values. An emerging presbyope will be most unhappy!
> 
> With the cost of optimized free-form lenses decreasing, approaching the cost of semifinished, it makes sense to take advantage of this technology. However, make sure that your clients have been provided with realistic expectations when the expected improvement in optics is small.


Robert, as ususal has a great answer.  Small addition:  If a SV Lens has prism you are likely to benefit much from Free-form powers.  Some stock Aspheric lenses esp Zeiss and Seiko can be really good for Mid powers, and lower cyls.  

My best guidelines are that over +2.50 to -4.00 sphere, anything with prism, and any cyl over -1.00 will see the best improvements in SV Free-form.  Anything over a +1.50 Cyl should be higher end free-form with POW Compensations (if you can get them).

----------


## scriptfiller

So far so good with the Auto III, we have successfully re-fit several Physio Enhanced pat's.

----------

