# Optical Forums > Progressive Lens Discussion Forum >  Varilux Physio comments & feedback please

## Bezza

I recently attended the launch for Varilux Physio here in the UK and during 2 days of being thoroughly looked after by Essilor, enjoying, fine food, entertainment, drunkeness and horse racing at cheltenham festival somehwere in there they mangaed to fit in a presentation regarding this new lens technology.:cheers: 
I have to say that it does look pretty special, mapping wavefronts through both surfaces and surfacing both surfaces to reduce coma and other high order abberations etc....all very clever stuff. All the Essilor staff at the event were saying that this was just the tip of the iceberg and that they have only just begun to understand the capabilities of this new technology, which they have 5 seperate patents for.  :Cool:  
Anyways I was just wondering what sort of reception this lens has received elsewhere as im sure that other countries have already been using it before us. Are you getting good responses from PXs using the lens and is it really as good as they say it is?
Anything else I ought to know before I start dispensing them to all our Panamic wearers?

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## rinselberg

*Information* is my game, not optics (per se); but I have a suggestion: Use the OptiBoard Search option. Search by Key Word *physio* and be sure to select Search Entire Posts and not Search Titles Only. Select "Search All Open Forums" and "Show Results as Posts". Execute your search with the Search Now button. I retrieved 193 posts in reverse chronological order. It's a good way to zero in on which OptiBoarders have actually dispensed any of these lenses, and what some of them had to say.

The answers are out there ...



nsofar as one _can_ define existentialism, it is a movement from the abstract and the general to the particular and the concrete ... http://mythosandlogos.com/

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## Chris Ryser

> *I recently attended the launch for Varilux Physio here in the UK and during 2 days of being thoroughly looked after by Essilor, enjoying, fine food, entertainment, drunkeness and horse racing at cheltenham festival somehwere in there they mangaed to fit in a presentation regarding this new lens technology*


If a company can still do product launch parties of that kind.........in the UK and how many other countries.................they for sure will price the product accordingly and count on major sales figures. 

The customer will always have to pay back advertising cost and original R&D in the price of the product.

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## Bezza

> If a company can still do product launch parties of that kind.........in the UK and how many other countries.................they for sure will price the product accordingly and count on major sales figures. 
> 
> The customer will always have to pay back advertising cost and original R&D in the price of the product.


apparently its gonna be priced the same as the panamic

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## Happylady

I have a pair of regular Physios in poly with AR. I have also worn Panamics with no problems. My distance correction is -2.00-.50 and -2.50 sphere with a +2.00 add.

The Physios are wonderful. The distance is excellent and so is the intermediate. The reading is good, I can see the width of a page of a book. Compared to my Sola Ones which I also like a lot the distance area is wider.

My husband has the Physio 360, his distance is about a +.75 -.50 and his add is +2.50. He also likes the lens a lot though he thinks his previous pair of Sola Ones have a wider reading area. I don't notice any difference with mine. Perhaps it has to do with the difference in the rx.

So far I have had no non adapts with the Physio. Several patients told me they could see very clearly. One patient told me she noticed no difference in the width of the distance area but her add did increase several steps.

I have one patient that I fit with the Physio 360 that hasn't been happy with progressives in the past but didn't want to try a lined bifocal yet. I checked her glasses in yesterday so I don't know what she thinks of them yet.

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## fjpod

I have always had difficulty wearing any progressive over my monovision Acuvue contact lenses.  For the most part, I see fine both distance and near with the CLs alone.  Now that I'm 51, there are occasions where I could use a little help with fine print and night driving.  (Although the real reason I got them is that my opticians on staff think should wear spectacles to boost sales.) 

So, I thought I would try physios, OD -.25sph,  OS -1.00, 2.00 add OU.  The distance and intermediate areas are truly wider and much more distortion free (IMHO).  The near zone is clear and seemingly wide enough...lateral head positioning for reading seems less critical.  The one weakness I think I have found is there seems to be more distortion in the inferior peripheral areas of the lens.  I guess you gotta put it somewhere.

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## AWTECH

The regular is produced just like the Panamic.

The 360 uses a point file produced surface.  

I do not understand the logic in calling these both a Physio but it is not my company.

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## chip anderson

AWTech:  

The 2 hour "instruction course"  (translantion:  Sales pitch) I sat through yesterday had a computerised chisel poiint (Kind of reminded me of the old manual Levin Lathe I made contact lenses on in my early days) doing the front surface only on the Physio.  It had same doing the surfaces on both sides for the 360 or whatever they called the delux model.

Sorry to disagree, but be of good heart.
I paid your bill today.

Chip

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## Bezza

> The regular is produced just like the Panamic.
> 
> The 360 uses a point file produced surface. 
> 
> I do not understand the logic in calling these both a Physio but it is not my company.


From what I understand the physio has the front surface adjusted and surfaced by their wavefront management software and back surface produced in the normal fashion, while panamic is merely a well designed back surface progressive.
The 360 on the other hand has both surfaces compensated and is surfaced using their point by point twinning surfacing technology, in other words both surfaces have the wavefronts mapped and compensated to reduce high order abberrations and unwanted astigmatism.

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## AWTECH

Bezza:


> From what I understand the physio has the front surface adjusted and surfaced by their wavefront management software and back surface produced in the normal fashion, while panamic is merely a well designed back surface progressive.
> The 360 on the other hand has both surfaces compensated and is surfaced using their point by point twinning surfacing technology, in other words both surfaces have the wavefronts mapped and compensated to reduce high order abberrations and unwanted astigmatism.


http://www.lasikinstitute.org/Wavefront_Technology.html Eye Surgery Education Council:


> Wavefront-guided LASIK is a promising new technology that provides an advanced method for measuring optical distortions in the eye. Measuring and treating these distortions goes beyond nearsighted, farsighted, and astigmatism determinations that have been used for centuries. As a result, physicians can now customize the LASIK procedure according to each individual patients unique vision correction needs. The treatment is unique to each eye, just as a fingerprint is unique. Wavefront systems work by measuring how light is distorted as it passes into the eye and then is reflected back. This creates an optical map of the eye, highlighting individual imperfections.


If wavefront technology measures the human eye to develop a custom lens, then how can this be done for each patient using prescription eyewear where the know input for the custom lens is limited to Sphere, Cylinder, Axis and Prism, plus frame dimensions for alignment?

I know the limits to customizing lenses using front molded lenses like Panamic is the limitation of traditional surfacing cutting only spherical cuts.  The Physio 360 and the Seiko Succeed Internal PAL a cut by point files.  I don't know the number of possiblities for the 360 but not counting prisim there are over 2,000,000 customized lenses available using the Seiko Succeed Internal PAL.  Each prescription is individually mapped to the available information.  Physio 360 does not have access to a map of the cornea for each patient and therefore can not be custom made to match each patients cornea, which is what most eyecare professionals have come to understand Wavefront technology does.  It is my opinion the some cleaver marketing is going on with the use ot the term W.A.V.E. Technology.  Notice the periods in the marketing material after the W.A.V.E.  

I am naturally open to seeing opposing or additional views on this W.A.V. E. Front technology from Essilor. (I am not saying anything negative about the quality of the Physio lens as I have not done any testing on this lens)

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## shellrob

I think it's great that a lot of you like the lens, I however am not sold yet. I have yet to be proven too that it's any better. I think it's just another ploy by essilor to get their lenses sold, even if it's not better. Someone once said awhile back on here...why don't they just improve the lenses we already use instead of creating more and more new lenses. It would make sense you would think. I think most of what all these manufacturers say nowadays is bologna.

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## Bezza

> Bezza: 
> 
> http://www.lasikinstitute.org/Wavefront_Technology.html Eye Surgery Education Council:
> 
> If wavefront technology measures the human eye to develop a custom lens, then how can this be done for each patient using prescription eyewear where the know input for the custom lens is limited to Sphere, Cylinder, Axis and Prism, plus frame dimensions for alignment?
> 
> I know the limits to customizing lenses using front molded lenses like Panamic is the limitation of traditional surfacing cutting only spherical cuts. The Physio 360 and the Seiko Succeed Internal PAL a cut by point files. I don't know the number of possiblities for the 360 but not counting prisim there are over 2,000,000 customized lenses available using the Seiko Succeed Internal PAL. Each prescription is individually mapped to the available information. Physio 360 does not have access to a map of the cornea for each patient and therefore can not be custom made to match each patients cornea, which is what most eyecare professionals have come to understand Wavefront technology does. It is my opinion the some cleaver marketing is going on with the use ot the term W.A.V.E. Technology. Notice the periods in the marketing material after the W.A.V.E. 
> 
> I am naturally open to seeing opposing or additional views on this W.A.V. E. Front technology from Essilor. (I am not saying anything negative about the quality of the Physio lens as I have not done any testing on this lens)


hrm some interesting points there, I don't really know about the Seiko Succeed so I cant really say much about that. Of course you are correct that without a map of the patients cornea the 360 does have some limitation but unless Essilor are being extremely clever about their marketing the fact remains that the 360 does something that no other lens on the market does. Although im sure that other manufacturers use very similar technologies to design their lenses and the wide range of ILDs offer compensated back surfaces but to be able to compensate both surfaces in combination to further optimise the wavefront is something altogether unique. I had some rather lengthy chats with some of the technical guys from Essilor while at the launch and they were really excited at the possibilities offered by this new technology. In theory this means that they now have the ability to put varying amounts of sph, cyl, prism on either/both surfaces and in any fashion they think will help to achieve better acuity, comfort and field of vision. 
Personally I think that the physio 360 is more than just another lens design with a bit of tweaking to the amount and position of unwanted astigmatism like the countless others we have had in the past, but hey suppose I better wait and see what my patients think of it too before i get too excited.

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## AWTECH

Bezza:


> Although im sure that other manufacturers use very similar technologies to design their lenses and the wide range of ILDs offer compensated back surfaces but to be able to compensate both surfaces in combination to further optimise the wavefront is something altogether unique. I had some rather lengthy chats with some of the technical guys from Essilor while at the launch and they were really excited at the possibilities offered by this new technology. In theory this means that they now have the ability to put varying amounts of sph, cyl, prism on either/both surfaces and in any fashion they think will help to achieve better acuity, comfort and field of vision.


Think about the advantage of compensating both surfaces.  If designing the lens could be done with a spherical front curve and the light waves are designed to be refracted throught the lens to optimize the vision rather than putting some non spherical surfaces on both sides of the lense, there is a big advantage.  The lens can be edged to fit the frame curve without overhange around a portion of the lens.

Also consider that Essilor does not have access to the patent that allows progressives to be produced on the back surface of a spherical lens.  If they could do it this way I would bet they would and all of the marketing material would tell you how much better a backside individualized lens is.  The keyhole effect.  Stand 10 away from a keyhole in a door. What can you see through the keyhole?  Now go up to the door and put you eye up to the keyhole; wow a wide field of vision.  This is a simple example of the advantage to a backside design.

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## neo724

Dispensed 1st pair of Physio lenses successfully and the patient had no real pros or cons but did say she could see clearly through all the zones.  I will add feedback if I get any.  Good Luck.

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## Samuel Jong

> Dispensed 1st pair of Physio lenses successfully and the patient had no real pros or cons but did say she could see clearly through all the zones. I will add feedback if I get any. Good Luck.


Have you ever compared with Zeiss Individual?

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## neo724

No my office does not use many zeiss products.

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## Jim Stone

Physio=Definity.  Same thing.

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## AWTECH

Jim Stone said:


> Physio=Definity. Same thing.


If you mean they are both progressive designs then same is accurate.  If you mean they are both the same designs this in not the case.  Essilor developed the Physio which is a traditional front side PAL and Definity was developed by Johnson & Johnson.  Essilor purchased the J&J lens business while they were about to launch the new Physio product.

There is also a product called the Physio 360 which is a partial front side progressive and partial backside progressive.  This is similar to the J&J Definity approach in that the Definity has a part of the add on the front.

It is my belief that the only reason both the Physio and the Definity have part on the front and part on the back is because they can not put the progressive all on the back of a sphere because this technology is patented by another company.

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## For-Life

> Jim Stone said: 
> 
> If you mean they are both progressive designs then same is accurate. If you mean they are both the same designs this in not the case. Essilor developed the Physio which is a traditional front side PAL and Definity was developed by Johnson & Johnson. Essilor purchased the J&J lens business while they were about to launch the new Physio product.
> 
> There is also a product called the Physio 360 which is a partial front side progressive and partial backside progressive. This is similar to the J&J Definity approach in that the Definity has a part of the add on the front.
> 
> It is my belief that the only reason both the Physio and the Definity have part on the front and part on the back is because they can not put the progressive all on the back of a sphere because this technology is patented by another company.


Who has the patent

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## AWTECH

ICE-TECH Advanced Lens Technologies has an agreement that allows us to produce lenses using  manufactured undered processes covered by US Patent No. 6,019, 470.  This patent is controlled by Seiko Epson Corp. 

We are the first in the US to offer the Seiko Succeed full backside progressive lens, (which is produced using processes covered by this patent).  In addition we are developing other progressive designs that will be available ICE-TECH Polarized Lenses.

We are a smaller niche lens company with unique products produced in our own high tech facility using our own processes.  This technology uses freeform lens processing.  We do not use any traditional lens production methods.

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## doclabs

Physio 360 (among many others) is an improvement to normal front side progressives. However, they do not surface the front side. It is a cast normal front side progressive that they say is digitally designed (marketing). The distance/intermed/near are all done on the front side (confronted essilor on this and they admitted this -pre-moulded progressive). The backside of the progressive is aspheric/atoric and that is where the freeform component comes it. This asphericity allows for less abberation in the periphery. 

Dont take my word for it. To find out if you have a front side progressive and an aspheric inside curve (physio 360 while physio is just a normal conventional prog) simply use a sag gauge on the front of the progressive in different areas and u will see that all of the progression is on the front of the lens. If you clock the back (on the two meridians) you will see that there is only the slightest amount of asphericity. An improvement or conventional progressives but by no means the holy grail. Fully internal progressive are the real deal.

With respect to essilor claiming their fix higher order abberations well, its a marketing lie. Why? You need to know what you are correcting for. You need an abberometer which measures a persons eye and the higher order abberations therein (opthonics does this). The you can use that mapping to recreate and fix the higher order abberations. However you must ask yourself... if someone adjust their glasses or moves their eyes... that fix is out the door because that fix is at a fixed point only. Marketing is what these big vendors do best. Their staff simply spout what they are told and like to dazzle and wow people with a whole bunch of complexities that are more weighted towards marketing vs truth. That said it is definately an improvement over normal progressives, however i believe fully internal progressive (sag on front reads spherical and full progression on back) is the way to go. Overcomes the inherent weaknesses of having to look through lens material before you can even get to the active curves of the lens (the progression on the front side of progressives)

Also there are dual patents issued in north america for fully internal progressives. Seiko has one, and so does Zeiss/Sola. This means everytime someone produces any internal progressive (their own included), they have to pay just over $3US each. This is the most probably reason why Essilor has not come out with there own fully internal yet (however i suspect they will because the patents are being fought in court). Keep in mind the Essilors and big vendors are marketing machines that know exactly how to successfully launch products and create buzz.

Cheers,

doclabs

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## doclabs

You are correct on all of the above except... FYI Physio360 is simply a front side progressive with an aspheric/atoric backside. There is no splitting of the progression, it is all on the front. The definity is the only one to due this to get around the patent and it is like a 0.25 add on the front (minimal as possibly).

Cheers,

Doclabs

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## Robert Martellaro

> You are correct on all of the above except... FYI Physio360 is simply a front side progressive with an aspheric/atoric backside. There is no splitting of the progression, it is all on the front. The definity is the only one to due this to get around the patent and it is like a 0.25 add on the front (minimal as possibly).
> 
> Cheers,
> 
> Doclabs


Doclabs,

According to the folks at Essilor (technical, not marketing) the 360 is not atoric.

The Definity has +.75 on the front, unless Essilor has changed it (fromm the original JJ product).

Regards,

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## drk

Robert:
It seems like you've done some "legwork" on these new progressives.

Would you care to summarize what you've uncovered, if it's in summary form?

"The Martellaro Report"?

P.S.  Doesn't Pete Hanlin post here, anymore?

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## Darryl Meister

As stated earlier, Varilux Physio 360 uses a traditional semi-finished front surface with an optimized Rx back surface that is produced using a typical free-form generating and polishing process.

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## AWTECH

> As stated earlier, Varilux Physio 360 uses a traditional semi-finished front surface with an optimized Rx back surface that is produced using a typical free-form generating and polishing process.


Darryl: What do you consider as typical free-form generating and polishing?

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## Traciangela

I do work for Essilor, so my opinion may not be as valued by some.  But I have sold glasses for 8 years before working here and recently put my husband who used to wear FT's in a Physio and he says that the distance is great and has adapted very well.  So, besides all of the training I have recieved on the product, I now really believe in Physio even more.:o

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## Robert Martellaro

> Robert: 
> 
> Would you care to summarize what you've uncovered, if it's in summary form?


Here's a list of all the lenses available in the U.S., along with power ranges and material options, including some info on lens design.

http://img15.imgspot.com/u/07/74/13/PALs0101174070311.jpg

On some browsers you may have to enlarge the image to see more detail. IE7 works fine.

I just had a new refraction- I'm going to try at least two of these lenses, three or four if I can get a decent discount.

Regards,

Regards,

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## Darryl Meister

> Darryl: What do you consider as typical free-form generating and polishing?


"Typical" free-form surfacing involves a CNC, single-point diamond-turning process followed by a CNC soft lap polishing process. I would say that the most common processes for spectacle lenses utilize a Schneider HSC (101, Smart, Master, etc.) for surfacing and a Schneider CPP for polishing. There are obviously a lot of machines out there from vendors like Satisloh and DAC, as well.

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## AWTECH

> "Typical" free-form surfacing involves a CNC, single-point diamond-turning process followed by a CNC soft lap polishing process. I would say that the most common processes for spectacle lenses utilize a Schneider HSC (101, Smart, Master, etc.) for surfacing and a Schneider CPP for polishing. There are obviously a lot of machines out there from vendors like Satisloh and DAC, as well.


Darryl:  I see you were referring to the mechanics of the process and not the design.

For those not that familiar with freeform lenses, they require a combination of a lens design and the freeform lens processing as Darryl described above.

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## Darryl Meister

> Darryl: I see you were referring to the mechanics of the process and not the design.


Secifically, I was referring to lens surfacing using common free-form generators and polishers, which is independent of the design. You can, for instance, surface a basic sphere using a free-form generator. Ultimately, "free-form" describes nothing more than a manufacturing platform.

I also don't really agree with the use of "free-form" as a meaningful description of lens designs (in fact, _all_ progressive lenses are technically "free-form" surfaces). Use of this term in such a way has unfortunately made it synonymous with premium, customized lens designs. While several products in the marketplace made using free-form surfacing offer advanced lens designs that have been truly customized for the individual wearer, not all so-called "free-form" lenses are customized -- or even superior to traditional, semi-finished lenses. This allows a lens supplier to hide inferior technology and application behind the "free-form badge."

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## AWTECH

Darryl Meister said:


> I also don't really agree with the use of "free-form" as a meaningful description of lens designs (in fact, _all_ progressive lenses are technically "free-form" surfaces). Use of this term in such a way has unfortunately made it synonymous with premium, customized lens designs. While several products in the marketplace made using free-form surfacing offer advanced lens designs that have been truly customized for the individual wearer, not all so-called "free-form" lenses are customized -- or even superior to traditional, semi-finished lenses. This allows a lens supplier to hide inferior technology and application behind the "free-form badge."


I agree with Darryl and see that there is much confusion over the words, Freeform and Wavefront in todays lens marketing.

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## Fezz

> I agree with Darryl and see that there is much confusion over the words, Freeform and Wavefront in todays lens marketing.



I totally agree with these guys. It is really amazing how cloudy and murky the use of these terms has made this. It is amazing how many "Opticians" don't have a clue.

But, I guess that could be the goal. Marketing has once again confused the buyers and they really don't know what they are TRULY getting. 

Its a shame.

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## AWTECH

Fezz said:


> I totally agree with these guys. It is really amazing how cloudy and murky the use of these terms has made this. It is amazing how many "Opticians" don't have a clue.
> 
> But, I guess that could be the goal. Marketing has once again confused the buyers and they really don't know what they are TRULY getting. 
> 
> Its a shame.


NOT DIRECTLY RELATED TO THE ORIGINAL TOPIC OF THIS THREAD:
To your point the new 20/20 has an add by Essilor for their new sunlens Crizal AR.  The add reads like they invented backside AR for a sun lens.  My company ICE-TECH introduced this on our products over 10 years ago.

But many people see something in print and take it for fact.

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## HarryChiling

Article on the free form process Here

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## Traciangela

I haven't seen the ad, but for the Crizal Sun, what we were told is that Essilor tried to determine why patient's did not like AR on their sun lenses and how to best use AR on Sun lenses.  They came up with a backside AR and a front side TD-2 (scratch resistance) so as not to change the apperance of the front surface and the other complaint found on their research was that a polarized lens reduces glare and doesn't need anti reflective coating on top of it.  The major difference to me in Crizal Sun and a regular lens with backside AR, is just the quality of the AR and the quality of the scratch resistance.  I had a pair very similar made before from an optical place that I worked for that had backside AR and was polarized and it was cheap AR and very easy to scratch.  :o

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## Tim Thurn

For your husband try a little more tilt on his frame, from my own experence and that of colleagues this makes all the difference, the same goes for all apsheric PALs

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## Tim Thurn

> Physio 360 (among many others) 
> 
> With respect to essilor claiming their fix higher order abberations well, its a marketing lie. Why? You need to know what you are correcting for. You need an abberometer which measures a persons eye and the higher order abberations therein Cheers,
> 
> doclabs


I admit that I am an absolute novice to positng on sights, I am usually content to just read. However, I have now seen a number of such comments and I feel I need to respond. I have no qualms about disclosing that I was an optometrist for 10 years and for the last 18years have worked for Essilor in various roles in Australia, France and now as Director of Professional Services for Asia Pacific. I know very well and worked closely with many of the scientists who work in the physiological and visual optics area of our R & D.

There are several points to address so I will take them one by one:

Aberrometry is not restricted to the eye, it originated from astronomy where it is used to clarify images from space seen through telescopes. When that same principle is applied to progressives, you can create a surface that corrects the wavefront as it passes through the lens reducing the aberrations that are normally generated by the progressive surface itself. Unlike aberrometry of the eye it can be done for many directions of gaze.

It is irrelevant if this surface is moulded or generated, it can be done either way, so long as the moulds are created using a "free-form" or digital direct surfacing machine that can replicate the wavefront corrected surface on the mould. We have used digital surfacing of moulds for more than 10 years and now apply that esperience to lens surfacing as well.

Remember that spectacle lenses are considered thin lenses, the wearer sees only the resultant vergences created by the two surfaces. Where they are positioned or when they are created doesn't matter, the resultant output does. This is why it is critical at the practitoner level that fitting is performed systematically, their role is to finish the process that is started by the manufacturer, correct fitting maximises the final output.

One thing I would like to undrstand is why the accusations? From my experience with the company and my close relationship with our R & D team Essilor is, like many French companies, steeped deeply in technology and innovation, R & D attracts far more of our budget than marketing 'lies'. The fact is that the market quickly decides what is innovation and what isn't. I've had the pleasure to dscuss at length with Bernard Maitenaz, he told me that when he launched Varilux 1 in 1959 there were more than 60 papers saying that the product was BS and would never work. It seems that that some things never change.

Best Regards

Tim

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## Darryl Meister

Welcome to the 'Board, Tim. I agree with your comments, but I wanted to pose some additional points that may further clarify this topic.




> Aberrometry is not restricted to the eye, it originated from astronomy where it is used to clarify images from space seen through telescopes.


I've never actually seen the use of the word _aberrometer_ or _aberrometry_ outside of eye care, so it would probably be useful to distinguish between so-called _aberrometers_ and _wavefront sensors_, in general. Commercial "aberrometers" use a wavefront sensor to measure _ocular_ wavefront aberrations, but you generally wouldn't refer to the wavefront sensor of a telescope--used in conjunction with an adaptive optics system to cancel atmospheric turbulence--as an "aberrometer."




> When that same principle is applied to progressives, you can create a surface that corrects the wavefront as it passes through the lens reducing the aberrations that are normally generated by the progressive surface itself. Unlike aberrometry of the eye it can be done for many directions of gaze.


I think there is a bit of a misconception here as to the type of wavefront aberrations we deal with in progressive lens design. Because of the inherent changes in Add power and unwanted astigmatism in a progressive, a progressive lens surface produces certain levels of higher-order aberrations (specifically, aberrations similar to coma and trefoil). This is simply a consequence of the progressive change in power. As long as you have a finite pupil size, and a change in mean power or astigmatism across that pupil, you will introduce coma or trefoil.

Further, you cannot eliminate the higher-order aberrations produced by a progressive lens surface, just as you cannot eliminate the unwanted astigmatism in the periphery. But you can judiciously manage both. And, just as there are two general approaches to the management of unwanted astigmatism, by either spreading it out to "soften" the design or confining it to smaller regions to "harden" the design, there are also two intimately related approaches to the management of higher-order aberrations. A "softer" lens design, for instance, will frequently produce relatively low levels of higher-order aberrations over the entire lens, while a "harder" lens design can produce lower levels of higher-order aberrations in the central distance and near viewing zones at the expense of higher levels around the viewing zone boundaries and in the progressive corridor.

In any event, traditional progressive lenses are not designed to minimize the higher-order wavefront aberrations produced by the wearer's own _eye_. First of all, there are several technical limitations involved because of the fact that the eye rotates behind the lens and higher-order aberrations do not possess the symmetry of the lower-order aberrations (i.e., traditional sphere and cylinder errors). Secondly, aberrometry data from the actual wearer's eyes need to be captured before any wavefront correction could be applied. And I believe that this was probably doclabs's point. That said, it _is_ certainly possible to minimize the higher-order aberrations produced by the _progressive lens_, itself, by optimizing the lens design accordingly, which is the heart of Essilor's claim.

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## kapthree

I see that Physio increases contrast sensitivity by up to 30%. Are there clinical trials or research on this?

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## Tim Thurn

I did speak to our R & D team about this and I can't remember if they were internal measures or outside, I'll get back on that one.

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## DragonLensmanWV

> Fezz said:
> 
> NOT DIRECTLY RELATED TO THE ORIGINAL TOPIC OF THIS THREAD:
> To your point the new 20/20 has an add by Essilor for their new sunlens Crizal AR.  The add reads like they invented backside AR for a sun lens.  My company ICE-TECH introduced this on our products over 10 years ago.
> 
> But many people see something in print and take it for fact.


Essilor did have their finished plano Sunfree lenses at least that long ago. Mirrored frontside, backside AR.
I still have a pair in my plano drawer.

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## Mr_Mitchell

I am confused, and would like Darryl to explain to me how it is that, according to the recent 20/20 CE article/advertisement, the physio is customized to the frame and the wearer?  If you look at the illustrations, it's just the same picture altered to give the appearance that the lens has been "customized," and further the lens isn't truly "free form" in the sense that the Autograph or Succeed is. 
I could be horribly, tragically wrong, which is why I ask that DM enlighten me.

----------


## Darryl Meister

> I am confused, and would like Darryl to explain to me how it is that, according to the recent 20/20 CE article/advertisement, the physio is customized to the frame and the wearer?


Are you sure it wasn't referring to the Varilux Physio 360 (with the free-form surface) or the new Accolade Freedom design?

----------


## OPTIDONN

Welcome Tim!! Enjoyed your post! I feel I understand the concept of higher order aberrations but I need a good explanation as to why they are called "higher order" and why are some called "3rd order" and how many are there to be exact!  :Confused:

----------


## Darryl Meister

> Enjoyed your post! I feel I understand the concept of higher order aberrations but I need a good explanation as to why they are called "higher order" and why are some called "3rd order" and how many are there to be exact!


The "orders" represent the terms of a mathematical power and/or Fourier series expansion (most commonly, Zernike functions), and go on indefinitely. Though, for "normal" eyes at least, the wavefront aberrations of the eye can be adequately described using no more than the fifth or sixth orders.

Each order indicates the dependence of the wavefront aberration on pupil size; the "second" order aberrations (modes) vary with the _square_ of the pupil radius, "third" order aberrations vary with the _cube_ of the pupil radius, and so on.

_Lower order_ terms refer to the traditional sphere (referred to as defocus) and cylinder components (referred to as astigmatism at 45 and at 180) of a typical eyeglass prescription. These are the _second order_ terms. Any wavefront aberration mode above these second order terms (that is, third order or greater) is considered a _higher order_ term. These include aberrations like coma (3rd), trefoil (3rd), spherical aberration (4th), etcetera. Higher order terms cannot be corrected by a simple sphero-cylindrical correction.

----------


## OPTIDONN

Thanks Darryl. Makes a bit more sense to me. I tried to ask that question on www.physicsforums.com and was even more confused. Nothing like some 13 year old genius to make you feel good about yourself :( .

----------


## AWTECH

> The "orders" represent the terms of a mathematical power and/or Fourier series expansion (most commonly, Zernike functions), and go on indefinitely. Though, for "normal" eyes at least, the wavefront aberrations of the eye can be adequately described using no more than the fifth or sixth orders.
> 
> Each order indicates the dependence of the wavefront aberration on pupil size; the "second" order aberrations (modes) vary with the _square_ of the pupil radius, "third" order aberrations vary with the _cube_ of the pupil radius, and so on.
> 
> _Lower order_ terms refer to the traditional sphere (referred to as defocus) and cylinder components (referred to as astigmatism at 45 and at 180) of a typical eyeglass prescription. These are the _second order_ terms. Any wavefront aberration mode above these second order terms (that is, third order or greater) is considered a _higher order_ term. These include aberrations like coma (3rd), trefoil (3rd), spherical aberration (4th), etcetera. Higher order terms cannot be corrected by a simple sphero-cylindrical correction.


Congradulations to Darryl Meister on his short yet very well rounded understandable explaination of high order abberations.  What I like best about his explaination is that most of the Optiboard readers can understand this, unlike some of the marketing driven pitchs using buzz words that no one in the company can explain.

----------


## Bobie

The performance of Varilux Physio 360 can not compare with Zeiss Gradal Individual. 

If you believe in Essilor and would like to get trouble , try to fit Physio 360 on Zeiss Gradal Individual's wearer. You will see the truth. ( Don't forget to think about how to refund the money to the wearers when they don't want to keep Physio 360 and who have to pay for useless lenses ).

----------


## Tim Thurn

> I see that Physio increases contrast sensitivity by up to 30%. Are there clinical trials or research on this?


Sorry for the late response, been a bit busy to look at the forum. The measures are simulations done by our R & D, measuring the gain in the contrast sensitivity function averaged across a particular lens e.g in this case Physio versus Panamic and for varing pupil sizes. I was sent a whole powerpoint about it by Celine Carimalo the chief researcher on Physio.

Hope this helps.

Regards

Tim

----------


## Bobie

Wave Front Free Form technology that used in Physio is technology of 1993. ( Rodenstock Multigressiv 2 )

----------


## Tim Thurn

> Wave Front Free Form technology that used in Physio is technology of 1993. ( Rodenstock Multigressiv 2 )


I am not sure how something that has just been patented in the last few years can be 1993 but you obviously have an axe to grind to push your sales. I find this type of discussion very disheartening, particularly in a place like Thailand. Around Asia in general the market is wanting to use the new technologies but often lacks the confidence, it is our job as manufacturers to build confidence in the use of progressives not undermine it by attacking the products we all wish to sell. 

There is plenty of room for all out there, if you are going to make comments supply the data that goes with it. I read just the other day in a Chinese newspaper that a prominent Internet pioneer is now anti the lack of regualtion of comment on the net as people can say anything without backing it up. The comment the other day about Gradal is the same, there will always be anecdotal points to be made about any product but where are the details - there are so many factors to consider; base curves; Rx; thickness and the wearer's own perception etc. There are many cases where the lens design gets blamed when it is just good old aniseikonia, as with any type of lens, altering perception and needing patient adaptation.

If you want to prove something do the research, give the data, back up your content. We spend $1 million a year educating practitioners and educators across the Asia Pacific through Varilux Academy once they have the skills they can see for themselves which products work for them.

----------


## Barry Santini

> If you believe in Essilor and would like to get trouble , try to fit Physio 360 on Zeiss Gradal Individual's wearer. You will see the truth.


My experience: I've fit Impression ILT until it was removed from the US market many years ago. I then switched to Zeiss Gradal Individual. This switch, for my *discriminating* clients, was seemless, and they continued to enjoy the Zeiss version for this class of freeform progressives. I must confess that I did not present this lens design class to all clients, many because of cost, fabrication time, and lack of the full array of lens options (transitions in particular). My pre-selected clients, whom I thought would recognize and enjoy (or had the *desire*) for the best progressive lens design available in the US, were presented this lens choice.

Now, I have enought (10) of these same Individual clients that I have switched into Accolade FREEDOM to report that they LOVE this lens equivalently to their Individuals. I am not making the claim that they are design/performance equivalent, only that they are accepted as such (anecdotally) by these discriminating clients.

With my experience using Darryl's wrap compensator, and having taken 100's of panto, face form and vertex distance measurements, I can see why using some typical defaults for these values in the Accolade Freedom design process does not materially change the Rx calculations when compared with specified/found values for Gradal individual. In fact, it appears that applying standard Rx tolerancing *and verification* is more crude by a factor of at least 3 compared to the additionally found/calculated precision of specified values for these parameters.

I have additionally found that almost all my clients respond enthusiastically to a switch in lens design from Comfort to (regular) Accolade.

Caveat: In all comments cited above, the Rx you begin with MUST be optimal for *that* client, i.e.:

1. Not overplussed (unless intended)
2. Corrected for astigmatism properly (amplitude and axis)
3. Not used in too short a fitting height, i.e., less than 17mm.

My current *seat-of-the-pants* experience, FWIW

Barry

PS - Accolade has essentially *killed* off my Physio and Physio 360 sales (and it certainly not for cost reasons, as they are similarly priced). Apologies to my Varilux rep.

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## Bobie

Sometime , some PALs company can close the sky with their hand , but it can not be forever , because nobody can hide the truth forever.

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## Kyle

Methinks some may have been sipping from the "Right in any light" cup...

I especially liked the statistic mentioned regarding some 2 million unique lens combinations.  Ever contemplate just what that means and how it stacks up to other lenses?  Let's see...5 base curves available with add powers from +0.75 to +3.50...Sphere range -9.00 to +5.00... Cyl range to -4.00...180 axes possible...

Heck, when you do the marketing math (akin to "man-math" which usually involves a fish), even a P6 looks impressive!

Essilor is marketing genius at its best.  They're great at giving the least amount of detail to entice the most amount of curiosity.  That's their job.  That opticians get caught up in the hype isn't accidental, either.  Does the Physio stack up?  It's a good design.  Is it the Bugatti of the lens world as Essilor suggests?  Nope, but with a good wax in the press room it sure does look pretty.

----------


## dbracer

> If a company can still do product launch parties of that kind.........in the UK and how many other countries.................they for sure will price the product accordingly and count on major sales figures. 
> 
> The customer will always have to pay back advertising cost and original R&D in the price of the product.


What's wrong with that?

Confused dbracer

----------


## dbracer

> Methinks some may have been sipping from the "Right in any light" cup...
> 
> I especially liked the statistic mentioned regarding some 2 million unique lens combinations.  Ever contemplate just what that means and how it stacks up to other lenses?  Let's see...5 base curves available with add powers from +0.75 to +3.50...Sphere range -9.00 to +5.00... Cyl range to -4.00...180 axes possible...
> 
> Heck, when you do the marketing math (akin to "man-math" which usually involves a fish), even a P6 looks impressive!
> 
> Essilor is marketing genius at its best.  They're great at giving the least amount of detail to entice the most amount of curiosity.  That's their job.  That opticians get caught up in the hype isn't accidental, either.  Does the Physio stack up?  It's a good design.  Is it the Bugatti of the lens world as Essilor suggests?  Nope, but with a good wax in the press room it sure does look pretty.


Kyle,

This is more profound than some might recognize. 

dbracer.

----------


## Kyle

This is to Tim, whose position and opinions I do respect:

How much profit does that million dollar "education" yield for Varilux?

Education for the sake of margin = advertisement.

Don't get me wrong.  I'm actually (and some would say bizarrely) in favor of some degree of homogenization of the industry in terms of education and training.  For instance, can you imagine a world where there were NO CEC's available?  Without the efforts of larger companies, the foundation of most opticians' education would be minimal at best - you have to get a start SOMEwhere.  That said, there is NO excuse, in my humble opinion, in spreading disinformation through lies of omission.

A large computer manufacturer once thought themselves infallible.  Reps always wore the same suit/skinny tie combination (and GOD, THOSE SHOES!!!) and for decades the company enjoyed the "largeness" of their "cobalt" creation.  The company rose to iconic levels, the name itself being used to describe products from other manufacturers (the Frigidaire/Xerox effect).  Ask someone in IT today whether this company's machines stand in the market and they might even reply, "Who?".  The marketing platform was there, but the products themselves were clearly not capable of the quick adaptation required in the market.

Touting a lens as being unique in the industry without providing actual and practical data to its retail distributors is extremely similar to what we see in the States every election year; playing politics is the art of manipulation for personal gain.  The clearly weighted presentations of your corporation are no different than those of many others, who ALSO have "educational" programs aimed at elevating the knowledge of ECP's, and are, at their most basic level, *political* in nature.

It is only through objective analysis that we find truly useful and helpful information.  Do not presume EVER the notion that we, this body of opticians locally and globally, aren't smart enough to figure out when our collective chains are being yanked.  However, if you're a large lens or frame manufacturer, don't ever presume that as promotion-chasing sheep we won't volunteer them for a price...say, a million dollars annually?  Heck, I might even go for a trip for 2 to...Lisbon?  Mostre-me o dinheiro!

Soas not to delve unnecessarily into my opinion of Essilor's "white papers", read this section at:
http://en.wikipedia.org/wiki/White_p...l_white_papers

And by the way, and a bit astray, why aren't all Colts lab results made public?  (Rhetorical)

BAHHHHHHHH

Now where's my daggum coffee...

----------


## dbracer

Kyle,

I don't necessarily disagree with your position. I need to research this thing better, but using Wikipedia doesn't lend you any credibility.  In fact it's a source of White Paper in itself -- maybe not in marketing ploys, but certainly in poorly researched claptrap. 

I keep hearing significant jealousy about Essilor's marketing ability. Let's stick to the facts here and quit knocking someone else's legitimate good points. Why haven't you improved your marketing. 

If marketing is done on lies, that's one thing. If it's done by driving home good points and not speaking at length on the bad ones, it's just good marketing.  Unless your saying that most of us dwell on the bad points of what we produce, and we all have those bad points. I know I don't to the former, and I do to the latter. So far I've heard none of the bad admitted by any of the companies represented on this thread. Only finger pointing.

All of you seem to expect me to believe that what you say is all correct and what they say is mostly wrong.  

Come on guys, lets here why some of you are still in a "small market" if your product is so good. If it's marketing, why haven't you done a better job so we aren't in this argument in the first place. And as for you "big market" guys, some of these "small market" people are obviously smart, and they have some damn good points.

And all of you on this thread have got to have better sources than Wikipedia. 

Respectfully,
dbracer

----------


## Kyle

Wikipedia as a source of useful information, thankfully, was not my point.  I also don't disagree with yours.  I enjoy reading your posts.  I welcome your criticism and am grateful for such an open forum.

As far as jealousy goes, I'm certain the "giants" have good programs and am extremely thankful for them, frankly - I benefit from those programs every day: my AR sales are definitely improved by Sola and Essilor's marketing (the 'bullet' lens is amazing!!!), progressive sales by that of Essilor and Zeiss and frame sales by marketing of every fashion designer on the planet.

In the long run, how many of these innovations would have come about were it not for extensive R&D driven by market research/positioning? Seriously!

Am I ticked that companies won't/can't, either by policy or contract, provide me with more comprehensive data to digest?  Yup.  Do I think they're evil because of that?  It really doesn't matter in the long run.  It is what it is.  Am I jealous because they have larger programs than I do?  Nope, but if I get an offer to sail to Bimini on the [insert giant corporation name here]-sponsored boat, I probably won't turn it down.  Just don't expect me to change my opinion on product XYZPDQ which has nothing to do with Wikipedia's validity as an information source.

----------


## dbracer

Kyle,

Points taken and noted.

Remember, you don't get to post, then say that some part of it is not your point.  Whatever you say is part of your point or you wouldn't have used it. 

In the words of G. Gordan Liddy, "Words mean things." 

Sometime what's said on here does change my opinions on certain products, after I've checked their validity. That's why I read these "educated" forums. If it doesn't change yours, so be it; but I'm unsure of why you bother, unless it is just to espouse your opinion. That's okay, I reckon. 

Still you've made some damn good points. And, you've influence some of my opinions. 

Respectfully,
dbracer

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## Kyle

Dr. DB,

I like the quote.

From my own experience sometimes less is more so I'll just say I hope the weather out there is as fantastic today as it is in Georgia.

I bet we'd have one hell of a great time on that boat to Bimini. ;)

Enjoy your day.

Kyle

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## dbracer

G'Day to ya, Kyle.

dbracer

----------


## Pete Hanlin

P.S. Doesn't Pete Hanlin post here, anymore?
Not nearly as often as I used to, unfortunately.  Between travel and work, there just isn't much time left in the day anymore.

Y'all take a pretty dim view of marketing people.  I work with ours every day, and they're a pretty nice- and responsible- bunch of folks.  Their challenge is trying to communicate product benefits to an audience who often doesn't really understand the product!

In this thread alone there are misconceptions that would be clarified if one _simply read the marketing_ provided with the product:
1.) Varilux Physio has a digitally-molded front and a traditionally surfaced back.
2.) Varilux Physio 360 shares the same front- but has a 360 Digitally Surfaced back.
3.) DEFINITY has +0.75 ADD on the back surface- with the remainder on the front (so a +2.00 ADD with have +1.25 on the front and +0.75 on the back).
4.) Putting all the progressive & distance power on the back surface of a PAL is a concept currently used by at least 4 manufacturers.

Finally, its one thing to have a real eye care professional who is confused and wants some illumination- but perhaps folks with financial interests in other products could spare us all the fabricated indignation when a major manufacturer brings a product to market.

PS- Varilux Physio 360 isn't the Bugatti of progressives, its the Jaguar XKR!
PPS- Statements of _"PAL X works soooo much better than PAL Y"_ are silly (and you can make X and Y any design you want).

----------


## dbracer

> PPS- Statements of _"PAL X works soooo much better than PAL Y"_ are silly (and you can make X and Y any design you want).


Pete,

I haven't looked into things well enough, yet, to separate the wheat from the chaff on some of your other "defense tactic" statements.  But in 30 years of prescribing all the PA's out there, I can say the quote hereinabove is true without a doubt. 

I ain't never prescribed a PA that works every time for every one, nor have I had a patient that will accept every PA at any time. 

Respectfully,
dbracer

----------


## Darryl Meister

> I ain't never prescribed a PA that works every time for every one, nor have I had a patient that will accept every PA at any time


I don't think it's possible for a single progressive lens design to work for everyone, simply because many people have vastly different visual needs. prescription requirements specific to that individual wearer. The presbyope who spends much of her day at a desk may benefit from a lens design with larger intermediate and near zones, whereas a commercial driver may benefit from a lens design with a large, clear distance zone. Similarly, a low hyperope who generally removes her spectacles to drive may prefer a larger near zone, whereas a low myope who removes her spectacles to read may prefer a larger distance zone. Individualized customization of lens designs based on this type of wearer feedback is one of the most meaningful applications of free-form technology, in my opinion.

----------


## Kyle

Pete,

You mean it's better than my '91 Accord? :shiner:

PS: I like market people.  They sell me produce.
PSS: I secretly admire large corporations.  They employ my patients. :bbg:

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## bren_03825

Now being a myopic astigmatic, and being an ABO certified Optician for about 16 years, and wearing progressives for 7 years....the Physio I had sucked compared to the Panamic, same frame, measurements, materials, etc.  The Physio 360 in plain poly with Alize Clearguard is the only lens I have been able to compare to my Multigressiv ILT.  Tis only my opinion, but Kudo's to Essilor for catching up and comparing to that lens.  For some of my patients, they like it better, some not as good.  The next lens I will be trying is the GT2 (having been secretly a Zeiss fanatic before the Multigressiv) I want to see if it is as good as I think it will be.  When I fit any patient (previous or new) with progressives, I will fit between these lenses, unless they want barebones, then I fall back to comfort, definity, VIP, XL.  The hardest thing is overcoming bad fits from outside eyeglass providers, imho.

----------


## dbracer

To Darryl Meister, Kyle, Tim Thurn, Awtech,

Let me ask a few questions here that confuse me about some of your comments. Please understand I’m not arguing with you. Ya’all seem pretty intelligent to me, and my retriever’s IQ is 10 points above mine. So you’ve nothin’ to fear from me. 

  I don’t care whose lens is best. I just want to know some things. I want to clear-up what seems illogical. 

  First a short explanation so we’re on the same page, as far as I can tell, in our understanding.

  Zernike coordinates are simply Cartesian coordinates with elevation (piston), tilt and yaw.  There are millions of them on a cornea.  But, ocular surgeons have found that if they work with that many, they get lost in the forest for the trees. So, 30 or 40 are adequate. 

  Now I’m sure an aberrometer could be used in any kind of optics, but to date, the name is, sorta, reserved for intra-ocular aberrations, but aberrometer is by no means a “patented” exclusive for ocular work.  For example, a tonometer measures ocular pressures, but tension is measured in other professions also: vascular tension for example.  They use tonometers. 

  Now aberration within the eye isn’t a problem unless a given eye is “missed with” such as by refractive surgery. What I mean is that I’ve never heard of an individual having problems with aberrations unless they’ve had cornea work or a disease causing the same effect.  The exception here being aberration caused by an optical device, and that’s not intra-ocular that is extra-ocular. Extra-ocular problems don’t have to do with intra-ocular aberrations. Right? 

  So in dealing with glasses and incident light the eye, intra-ocular aberration doesn’t come into play because the eye has no aberration problems as long as we can make the incident light resemble that to which it is accustomed. 

  So why would and optical lens engineer need to determine individual corneal aberration since the eye itself doesn’t have any problems? It hasn’t been altered to cause intra-ocular aberration such that wave front analysis and Zernike polynomials are needed. 

  So if the light coming out of the back of the lens has properties similar to what the eye is accustomed, why would a company have to analyze each eye?  Wouldn’t it be adequate to simply make incident wave fronts more of the normal type?



Respectfully,
dbracer

----------


## Darryl Meister

> Zernike coordinates are simply Cartesian coordinates with elevation (piston), tilt and yaw. There are millions of them on a cornea. But, ocular surgeons have found that if they work with that many, they get lost in the forest for the trees. So, 30 or 40 are adequate.


I may not entirely understand your question here.

Typically, Zernike basis functions are generally expressed in either polar (radius, angle) coordinates (not entirely unlike a Fourier series) or, less commonly, Cartesian (x, y) coordinates. After measuring the height of a given surface, such as an aberrated wavefront, over a sufficient number of points, the surface can then be "fitted" with these Zernike basis functions using least-squares techniques. Just as you can build a rather complex looking house out of a combination of simpler shapes, such as squares and rectangles, Zernike basis functions can "build" a complex surface shape when added together.

However, the actual Zernike aberrations are generally expressed by their _orders_ and _modes_, though the first few have relatively common-ish names like "defocus," "astigmatism at 045," "vertical coma," etcetera. Each Zernike aberration has a coefficient associated with it that indicates the quantity of that particular aberration present in the surface shape -- that is, the "size" of the basis function.




> Now I’m sure an aberrometer could be used in any kind of optics, but to date, the name is, sorta, reserved for intra-ocular aberrations, but aberrometer is by no means a “patented” exclusive for ocular work.


True. Though, in other optical applications, the device is typically referred to as a _wavefront sensor_.




> Now aberration within the eye isn’t a problem unless a given eye is “missed with” such as by refractive surgery.


Uncorrected higher-order aberrations can reduce the quality of vision to some extent, though probably less than most people are willing to tolerate, anyway. These aberrations generally limit the ultimate resolving power of the eye though, and once they are eliminated the resolving power of the eye becomes limited by diffraction and the neural density of the retinal mosaic.




> So in dealing with glasses and incident light the eye, intra-ocular aberration doesn’t come into play because the eye has no aberration problems as long as we can make the incident light resemble to which it is accustomed...


Just so we're on the same page here, we have been discussing progressive lens designs that claim to reduce the higher-order aberrations produced by the _spectacle lens_, itself, not the higher-order aberrations of the wearer's actual _eye_ -- though this is a common misconception. Due to the variation in refractive error across the surface, progressive lenses introduce coma-like and trefoil-like wavefront aberrations. Unfortunately, you cannot really eliminate these aberrations, just as you cannot eliminate unwanted surface astigmatism. However, you can _manage_ them, just as you can choose to use either a "harder" or "softer" lens design to manage astigmatism accordingly. Lower gradients of power, for instance, will reduce coma; however, in order to obtain the desired change in Add power over a reasonable distance, you still need to have high gradients of power -- and, consequently, high coma -- _somewhere_ along the progressive corridor.




> So if the light coming out of the back of the lens has properties similar to what the eye is accustomed, why would a company have to analyze each eye? Wouldn’t it be adequate to simply make incident wave fronts more of the normal type?


Unfortunately, the only higher-order aberration that has an actual "trend" in the normal population is _spherical aberration_, which isn't actually produced by most spectacle lenses anyway, since the small pupil of the eye limits -- or "stops down" -- the diameter of the ray bundles leaving the spectacle lens. The other higher-order aberrations are pretty much "normally" (in the Gaussian sense) distributed.

----------


## Pete Hanlin

I haven't looked into things well enough, yet, to separate the wheat from the chaff on some of your other "defense tactic" statements.
Simply trying to clarify some of the (sometimes humorous) mistatements of fact regarding various products...  Its amazing how some individuals can complain so vehemently about material they've obviously never read.  Your dispensing experience is similar to my own- there's no peg that fits in every hole.

Personally, I think if you're using a PAL and are happy with its performance, then you obviously have a good thing going and should stick with it.  Nearly any PAL is going to be better than a segmented bifocal when it comes to visual performance, so I'm more interested in seeing the market do a better job of recommending PALs to patients than I am in arguing how good one design is compared to another.

That said, I happen to work for the manufacturer of Varilux, DEFINITY, and other PALs.  So, the most important thing to me is that _I'm_ convinced Essilor's PALs are the best in the world (because it would be quite depressing if I didn't believe that)- if I'm able to convince others of the merits of Essilor's PALs, that's just icing on the cake.

----------


## dbracer

> I haven't looked into things well enough, yet, to separate the wheat from the chaff on some of your other "defense tactic" statements.
> Simply trying to clarify some of the (sometimes humorous) mistatements of fact regarding various products...  Its amazing how some individuals can complain so vehemently about material they've obviously never read.  Your dispensing experience is similar to my own- there's no peg that fits in every hole.
> 
> Personally, I think if you're using a PAL and are happy with its performance, then you obviously have a good thing going and should stick with it.  Nearly any PAL is going to be better than a segmented bifocal when it comes to visual performance, so I'm more interested in seeing the market do a better job of recommending PALs to patients than I am in arguing how good one design is compared to another.
> 
> That said, I happen to work for the manufacturer of Varilux, DEFINITY, and other PALs.  So, the most important thing to me is that _I'm_ convinced Essilor's PALs are the best in the world (because it would be quite depressing if I didn't believe that)- if I'm able to convince others of the merits of Essilor's PALs, that's just icing on the cake.


Can't argue much with a straight up statement like that.

Respectfully,
dbracer

----------


## dbracer

I think Mr. Meister is correct. I didn’t communicate my question well. 

    The first few paragraphs are to establish level of understanding. I ain’t smart but I did spend the best part of my youth in terrible dingy, musty, stale science and math class rooms. Some of it actually stuck to a dull knife. I was just trying to say I begrudgingly spent as many college hours in trig, calculus and physics as the next guy.
    I’ll do some of it again.

*Level of understanding coordinates (not a question):*
    Cartesian coordinates are not limited to a simple quadratic, two dimensional abscissa and ordinate plots. They can also include the z-axis converting quadrants to octants and 3-deminsional space. 

    You can explain the Zernike surface development by formulation like Mr. Meister or you can more practically describe it as:

    Taking x,y,z Cartesian coordinate then adding to it formulated curvatures front and back, left and right establishing tilt and yaw like an airplane, ultimately establishing not only precise location, but also orientation. 

*Knowledge of the term aberrometer (not a question):*
    Tscherning actually called the original instrument for observing the distortions in ones own eye an aberroscope.  We’ve always called the sophisticated device used today an aberrometer, but I’ve never thought of an aberrometer as being exclusively an eye care instrument. 

    The reason is, if you look in such reputable reference as Dorland’s Medical Dictionary, Stedman’s Medical Dictionary, and The Dictionary of Visual Science by Schapero, Cline, Hofstetter they give the definition as “An instrument for measuring aberrations in experiments or observations.” They are not limited to optics. Mr. Meister must be only familiar with the intra-ocular ones. According to these sources an aberrometer typically called something else remains and aberrometer.   What’s typically called a runway by a duck is referred to as water by a Chukar. 

So, even though it’s my field, I think that declaring “aberrometer” mainly an ophthalmic &/or medical optics term is stretching the truth a bit to benefit ones own point of view, which I find a source of aggravation on these threads. So Mr. Miester, Mr. Thurn has you on that one. 

*The Questions*:
*I’m not discussing whether anyone is even doing wave front analysis on lenses currently.*  The question has nothing to do with coordinates, aberrometers or 3rd of 4th order aberrations.    

    The question is why do we need to analyze an individual’s intra-ocular aberration when, with spectacle lenses, we are dealing with extra-ocular wave fronts before they even reach the eye?

    If the incident wave fronts are made more like the ambient wave fronts to which the patient is accustomed then there will be less distortion perceived, because I know of no one who, with their "stand alone eyes," complains of aberration unless their eyes are diseased or surgically altered. 

    So why can’t we use wave front analysis to determine a more appropriate extra-ocular incident light pattern with out considering each individual?

Respectfully,
dbracer

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## optigrrl

> Physio 360 (among many others) is an improvement to normal front side progressives. However, they do not surface the front side. It is a cast normal front side progressive that they say is digitally designed (marketing). The distance/intermed/near are all done on the front side (confronted essilor on this and they admitted this -pre-moulded progressive). The backside of the progressive is aspheric/atoric and that is where the freeform component comes it. This asphericity allows for less abberation in the periphery. 
> 
> Dont take my word for it. To find out if you have a front side progressive and an aspheric inside curve (physio 360 while physio is just a normal conventional prog) simply use a sag gauge on the front of the progressive in different areas and u will see that all of the progression is on the front of the lens. If you clock the back (on the two meridians) you will see that there is only the slightest amount of asphericity. An improvement or conventional progressives but by no means the holy grail. Fully internal progressive are the real deal.
> 
> With respect to essilor claiming their fix higher order abberations well, its a marketing lie. Why? You need to know what you are correcting for. You need an abberometer which measures a persons eye and the higher order abberations therein (opthonics does this). The you can use that mapping to recreate and fix the higher order abberations. However you must ask yourself... if someone adjust their glasses or moves their eyes... that fix is out the door because that fix is at a fixed point only. Marketing is what these big vendors do best. Their staff simply spout what they are told and like to dazzle and wow people with a whole bunch of complexities that are more weighted towards marketing vs truth. That said it is definately an improvement over normal progressives, however i believe fully internal progressive (sag on front reads spherical and full progression on back) is the way to go. Overcomes the inherent weaknesses of having to look through lens material before you can even get to the active curves of the lens (the progression on the front side of progressives)
> 
> Also there are dual patents issued in north america for fully internal progressives. Seiko has one, and so does Zeiss/Sola. This means everytime someone produces any internal progressive (their own included), they have to pay just over $3US each. This is the most probably reason why Essilor has not come out with there own fully internal yet (however i suspect they will because the patents are being fought in court). Keep in mind the Essilors and big vendors are marketing machines that know exactly how to successfully launch products and create buzz.
> 
> Cheers,
> ...


Thank you for putting it so succinctly. Don't forget the Hoya iD.

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## Darryl Meister

First of all, let me say that I do enjoy discussing this sort of stuff, and I'm glad to have run across a few individuals who actually have a genuine interest in this topic.




> I was just trying to say I begrudgingly spent as many college hours in trig, calculus and physics as the next guy... *Level of understanding coordinates (not a question):*


At the end of the day, coordinate systems are just a means to express a location in a multi-dimensional space. It just so happens that some of them are more convenient than others for a particular application (e.g., rectangular/Cartesian, polar, curvilinear, etcetera). That is to say, the use of one coordinate system over another may simplify the mathematics involved, once the initial transformations to the chosen coordinate system have been completed. And you can certainly convert from one coordinate system to the another in many (if not most) cases, assuming they at least represent the same multi-dimensional space, that is.

I suspect that the Zernike basis functions (i.e., Zernike "aberrations" or "modes") all look pretty much alike when the surface also looks the same in a given coordinate system.




> So, even though it’s my field, I think that declaring “aberrometer” mainly an ophthalmic &/or medical optics term is stretching the truth a bit to benefit ones own point of view, which I find a source of aggravation on these threads. So Mr. Miester, Mr. Thurn has you on that one... Mr. Meister must be only familiar with the intra-ocular ones


Keep in mind that I have already distinguished between wavefront sensors used in ophthalmic applications (i.e., "aberrometers") versus wavefront sensors used in other applications (e.g., adaptive optics for telescopes) in post #39, so I am certainly familiar with the use of these devices in non-ophthalmic contexts.

As I noted in that same post, I have only ever seen the term "aberrometer" (as applied to _wavefront measurements_) used in ophthalmic applications, but I certainly won't discount the possibility that someone -- somewhere -- has applied it in a different context. For that matter, much of our ophthalmic vernacular has subtly different meanings in other fields and contexts. In any event, I think you will find that modern usage of the term almost inevitably refers to a wavefront sensor used for measuring _ocular_ aberrations.

And, certainly, this is the common meaning of the term in modern vision science literature. Further, as you noted, Tscherning did not call his device an "aberrometer" (not that "aberrometer" is anything more than "aberration" and "meter" combined). However, if you find a specific -- and reasonably common -- reference to the use of the word "aberrometer" in a different ophthalmic context, or in a non-ophthalmic context, I would happily reevaluate this assumption. In the meantime, I would argue that a typical astronomer would still look at you in confusion if you referred to an "aberrometer," while a typical ophthalmologist would immediately identify it as a device for measuring _ocular_ wavefront aberrations.




> The question is why do we need to analyze an individual’s intra-ocular aberration when, with spectacle lenses, we are dealing with extra-ocular wave fronts before they even reach the eye?... So why can’t we use wave front analysis to determine a more appropriate extra-ocular incident light pattern with out considering each individual?


The short answer is that we do _not_ need to analyze the wavefront aberrations of the wearer to minimize the wavefront aberrations produced by the _spectacle lens_. However, there is no way around analyzing the wavefront aberrations of the actual eye before attempting to correct those -- at least beyond assuming a nominal correction for spherical aberration.

But keep in mind that a spectacle lens cannot fully eliminate the wavefront aberrations of the eye, anyway, without introducing additional lower- and higher-order aberrations as the eye rotates behind the lens.




> ...Mr. Meister...


post-scriptum,
It's just "Darryl." ;)

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## Andrew Weiss

First, this is one of the most educational threads I've encountered on the board in awhile (another is the Vision Source progressive thread).  I'm really grateful for the presence of people like Darryl, Kyle, dbracer and others who not only have the knowledge but also the ability to explain things simply and clearly.  What a gift!   Thanks to you all.

And to Tim -- g'day mate, welcome aboard!  My wife hails from Melbourne; we have family there and in Brisbane, Sydney and Hobart.  Whereabouts are you based?  And don't take things here too seriously. The attitude toward Essilor is a combination of some not-so-great experiences and more than a bit of "tall poppy" syndrome.

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## dbracer

Good post,

You're right. Coordinates drive me nuts, and there just a means to a location end. 

You're right. Just like a lot of "ometers" out there, aberrometer is just a combination of syllables.




> However, there is no way around analyzing the wavefront aberrations of the actual eye before attempting to correct those -- at least beyond assuming a nominal correction for spherical aberration.


But aren't you begging the question here? Why do we need to analyze the eye when the wearer of an unaltered eye has no complaints? He only has complaints with the spectacle alteration of incident light, right?




> But keep in mind that a spectacle lens cannot fully eliminate the wavefront aberrations of the eye, anyway, without introducing additional lower- and higher-order aberrations as the eye rotates behind the lens.


Here again the unaltered eye has no aberrations of human concern until the spectacles alter incidence, right?  

The industry has done a pretty good job of dramatically improving the PA distortion and disorientation from those of the old AO progressive first introduce in the 70's.

So I would think that using wave front analysis could further improve the industry. 

Respectfully,
dbracer

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## dbracer

> First, this is one of the most educational threads I've encountered on the board in awhile (another is the Vision Source progressive thread).  I'm really grateful for the presence of people like Darryl, Kyle, dbracer and others who not only have the knowledge but also the ability to explain things simply and clearly.  What a gift!   Thanks to you all.
> 
> And to Tim -- g'day mate, welcome aboard!  My wife hails from Melbourne; we have family there and in Brisbane, Sydney and Hobart.  Whereabouts are you based?  And don't take things here too seriously. The attitude toward Essilor is a combination of some not-so-great experiences and more than a bit of "tall poppy" syndrome.


Your are definitely overrating me, and putting me in a class of my superiors, but I'll take the compliment anyway. 

Respectfully,
dbracer

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## Darryl Meister

> But aren't you begging the question here? Why do we need to analyze the eye when the wearer of an unaltered eye has no complaints?


But I'm not suggesting that we _do_ need to measure them. I'm simply saying that the aberrations produced by the _spectacle lens_ are independent of the aberrations produced by the _eye_, though they will obviously interact to some degree, and that if you _want_ to minimize the aberrations of the eye, you need to know what they are, first (using a wavefront sensor, for instance).




> Here again the unaltered eye has no aberrations of human concern until the spectacles alter incidence, right?


This quote was originally referring to lenses that have attempted to minimize any higher-order wavefront aberrations of "human" concern. The spectacle lens can correct those aberrations only for a single angle of view. As for whether or not those higher-order ocular aberrations should've been corrected in the first place, I guess it would really depend upon the individual wearer. Though, in general, I think you are much better off getting a carefully determined second-order correction that considers the "effects" of the higher-order aberrations on lower-order sphere and cylinder errors and maximizing the depth of focus of the eye over a wide range of luminance levels.




> The industry has done a pretty good job of dramatically improving the PA distortion and disorientation from those of the old AO progressive first introduce in the 70's.


Yes, indeed. And those aberrations are considerably more detrimental to vision than the higher-order aberrations (of either the spectacle lens or the eye).




> So I would think that using wave front analysis could further improve the industry


You may have lost me here; I thought you were arguing _against_ the necessity of measuring and correcting higher-order wavefront aberrations...?

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## drk

Summary:
Physio: lens' higher order aberrations.
I-zon: eye's higher order aberrations (claim).
Custom ablation: ablation pattern's higher order aberrations.

Now, the nagging residual questions:
1.) Definity only puts +0.75 on the back? That's not that big a deal. I'm suprised.

2.) Is there higher-order lens aberration control in other designs?

3.) How much bang does an internal progressive provide? Yeah, the keyhole effect, and all, but maybe 2mm in a low minus lens matters. I guess I can understand that 5mm in a thick minus lens matters.

How about that, low power thin lenses vs. high power thick lenses and the variable keyhole effect?

4.) How to conceptualize the optical advantage of two-sided digital surfacing in the distance portion? How is 5 + 5 better than 10 + 0 ?

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## dbracer

> You may have lost me here; I thought you were arguing _against_ the necessity of measuring and correcting higher-order wavefront aberrations...?


lol, Darryl. We're now becoming a comedy of errors, mainly because of my poor communication skills.

No, I'm actually supporting consideration of higher order aberrations in PA's, or high &/or unusual powers to provide more optically compatible and acceptable lenses.

The intra-ocular higher order aberrations aren't part of this picture, because the average human wearer of unaltered healthy eyes has no problem with them. The higher order aberrations caused by the correcting lenses is what disorients the patient. 

In that same line of reasoning, I think some of the refractive surgery technology just might be helpful in producing better PA's, and other complex lenses.

What do you think, Darryl?

Respectfully,

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## dbracer

> Summary:
> Physio: lens' higher order aberrations.
> I-zon: eye's higher order aberrations (claim).
> Custom ablation: ablation pattern's higher order aberrations.
> 
> Now, the nagging residual questions:
> 1.) Definity only puts +0.75 on the back? That's not that big a deal. I'm suprised.
> 
> 2.) Is there higher-order lens aberration control in other designs?
> ...


Hey drk,

I think you may have some pretty good questions here.  I just don't quite understand them -- not that I have the answers.

Could you expound a little? 

Respectfully,
dbracer

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## Darryl Meister

> The intra-ocular higher order aberrations aren't part of this picture, because the average human wearer of unaltered healthy eyes has no problem with them. The higher order aberrations caused by the correcting lenses is what disorients the patient.


As it turns out, the higher-order aberrations produced by modern progressive lenses are seldom greater in magnitude than the higher-order aberrations of the wearer's own eyes (see, for instance, Villegas _et al.,_ "Spatially Resolved Wavefront Aberrations of Ophthalmic Progressive-Power Lenses in Normal Viewing Conditions" _Optom. Vis. Sci._ Vol. 80, No. 2). Secondly, lower-order astigmatism and defocus dominate most of the progressive lens surface. One could conceivably argue that small amounts of higher-order aberrations may increase the wearer's depth of focus and, consequently, improve the wearer's tolerance to the blur by the second-order aberrations of the progressive lens.




> In that same line of reasoning, I think some of the refractive surgery technology just might be helpful in producing better PA's, and other complex lenses


I'd hate to see wavefront correction referred to as "refractive surgery technology," simply because this technology was around long before refractive surgeons ever started using it. Also, while the goal of wavefront-guided ablation is often to achieve supernormal visual acuity by correcting higher-order aberrations, this goal is seldom realized. While wavefront-guided ablation certainly minimizes the wavefront aberrations traditionally produced by the refractive surgery, itself, such as spherical aberration, clinical studies have demonstrated that postoperative results are frequently no better than the patient's best corrected acuity prior to surgery.




> Now, the nagging residual questions


Hasn't this Physio thread been derailed enough? ;)




> 2.) Is there higher-order lens aberration control in other designs?


Some lens designs result in inherently low levels of higher-order aberrations because of specific choices made by the lens designers, such as minimizing the gradients -- or rates of change -- in power and astigmatism. Certainly, the presence of higher-order aberrations in a progressive lens surface as a result of rapid changes in power have been long understood. I have a 25-year-old book from Mo Jalie that discusses these optical principles in detail.




> 3.) How much bang does an internal progressive provide?... How to conceptualize the optical advantage of two-sided digital surfacing in the distance portion? How is 5 + 5 better than 10 + 0 ?


In terms of astigmatism and blur, the differences are negligible between front versus back versus dual surface designs, since 5 + 5 does indeed equal 10 + 0 (at least for thin-ish spectacle lenses).

Still, one could argue that moving the optics to the back surface 1) Brings the limiting apertures closer to the eye thereby slightly increasing the fields of view, 2) Reduces distortion since differences in front surface curvature contribute to magnification effects, and 3) Minimizes the potential for surface alignment errors. Lastly, if you believe that free-form surfacing produces a more accurate lens surface, one could also argue that it is better to free-form surface the progressive lens design, not just the optimized prescription curves.

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## drk

You are most kind, and most wise, Darryl-san.  

Your dilligent responses fill the oceans

with deep waters of understanding..:D

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## Pete Hanlin

Physio: lens' higher order aberrations.
I-zon: eye's higher order aberrations (claim).

Concisely put...  The visual system of an ametrope consists of both the eye itself plus any corrective lens placed in front of the eye.  Therefore, higher order aberrations in either the eye OR the corrective lens will increase the higher order aberrations of the system (and decrease the modulation transfer function of the system- which results in a lower contrast sensitivity threshold).

Ophthonix has a system that measures higher order aberrations in the eye, then attempts to resolve those aberrations with the corrective lens.  Varilux Physio, Varilux Physio 360, and Varilux Ipseo reduce the higher order aberrations in the corrective lens, but do nothing to correct higher order aberrations in the eye itself.  The progression of Varilux Physio & Varilux Physio 360 is placed entirely on the front of the lens- the progression of Varilux Ipseo is placed on the back (along with the distance power).

As Darryl notes, some PALs inherently have less higher order aberration than others- simply as a result of other design characteristics.  W.A.V.E. Technology is a design characteristic specifically focused on lowering higher order aberrations.  As a result, lenses with WAVE Technology have little or no higher order aberration in the area of the lens primarily used for distance viewing.

Definity only puts +0.75 on the back? That's not that big a deal. I'm suprised.
Well, J&J thought it was a big deal when they launched DEFINITY, and Essilor must have thought it a big enough deal when they subsequently purchased the technology.  The primary feature of DEFINITY is low levels of unwanted astigmatism.  Typically, you can change a PAL wearer from a +1.50 ADD in a traditional (front surface only) PAL, change them to a DEFINITY, and- even if the ADD power in the new lenses is +2.00- the level of unwanted astigmatism will decrease in the new DEFINTY lenses.

Best regards,
Pete

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## Darryl Meister

> Ophthonix has a system that measures higher order aberrations in the eye, then attempts to resolve those aberrations with the corrective lens.


I agree that they are measuring the higher-order aberrations of the eye with their aberrometer, though I would argue that it is mathematically impossible to correct those aberrations fully with a spectacle lens, at least without introducing additional higher- _and_ lower-order aberrations as the eye rotates behind the lens.

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## Pete Hanlin

I agree that they are measuring the higher-order aberrations of the eye with their aberrometer, though I would argue that it is mathematically impossible to correct those aberrations fully with a spectacle lens, at least without introducing additional higher- _and_ lower-order aberrations as the eye rotates behind the lens.
In a nutshell, I'm sure that's the question folks from Ophthonix hear most often (I know that's the one I asked them during their SILMO presentation a couple years ago).

Without attempting to speak for another company, the reply I recall was something to the effect that the visual axis usually remains relatively close to the center of the lens.

While I can accept that the eye probably does stay within a few mm of the OC (especially when looking steadily at a distance object- such as a TV or a road at night), the question then becomes one of how the lenses are fit.  I would imagine to have any benefit the frames would have to be fit with zero pantoscopic tilt with the OC positioned directly in front of the eye.

I've been measured on the iZon (aberrometer) machine, which indicated I have significant spherical aberration in my cornea (not surprising, since I had LASIK 5+ years ago and have noticed some aberration at night).  I'm hoping to try the Ophthonix lenses at some point (unfortunately, they "don't trust" the readings they get at Expo- so I have to make it to an office with the equipment)- just to see if there is any observable improvement in my night vision.

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## Darryl Meister

> While I can accept that the eye probably does stay within a few mm of the OC (especially when looking steadily at a distance object- such as a TV or a road at night), the question then becomes one of how the lenses are fit. I would imagine to have any benefit the frames would have to be fit with zero pantoscopic tilt with the OC positioned directly in front of the eye.


I do agree that the line of sight remains within, say, 14 or 15 degrees of the optical axis of the lens under static viewing conditions. Head- and eye-tracking studies have demonstrated that this is a reasonable cut-off before the eye begins to execute a compensatory head movement. (In fact, +/-15 degrees (30 degrees total) is almost exactly the width of a sheet of paper at 40 cm reading distance. However, at the spectacle plane, this represents a total range of over 13 mm, which is easily up to 3 pupil diameters under typical lighting conditions. And vertical head rotation probably varies depending upon both the person and the viewing task.

Now, if the line of sight moves just _one-half_ of a pupil diameter from an "ideal" correction, the induced aberrations around this "sweet spot" exceed the level of correction provided within the "sweet spot." That is to say, if the eye moves just a few millimeters from the center of a zone that has been perfectly corrected for higher-order aberrations, you can actually introduce higher levels of aberrations than you eliminated within the zone, itself. Of course, this isn't to suggest that Ophthonix is providing an "ideal" correction at any point on the lens; they have been very vague about how their lenses actually work, as far as I can tell.

Also, keep in mind that this all assumes the lens has been _exactly centered_ in the first place. Do they require monocular PD and fitting height measurements for their single vision lenses?

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## drk

Pete, if +0.75 back surface add is good, I'm sure the logic dictates that the full add on the back is very, very good.

I've tried to experiment with a pinhole...field of view with 1 mm pinhole smashed into eye socket (vertex ~ 0) is roughly 15 degrees at 40 cm...

...drops to ~half of that @ ~+5 mm vertex distance...very dramatic...

...certainly this reduction in field of view is linear with vertex distance...

...but certainly aperture size is another variable, and that probably is non-linear...(thinking exponent of 2, since area seems to work that way...)

Who knows how much additional field of view a ~15 mm wide near zone aperture gives with an ~5mm reduction in vertex distance? Can't be more than the order of 10-30&#37;. Not peanuts, though...

Totally unrelated visual science thought: Darryl, I noted that you say studies show that if the peripheral object if regard is within approx. the central 30 degree visual field, no head movement is made to fixate the object, but only an eye movement.

Interestingly, we seem to have arrived at 30 degrees as the "gold standard" for visual field testing in perimetry, as well.

Synthesizing all this, it's almost as though if a peripherally viewed object falls within our favorite 30 degree from fixation field of view, we will acquire it with a simple eye movement, but if the peripheral object is outside the 30 degrees, we will know to move our head, too. 

Just fun stuff.

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## dbracer

> I'd hate to see wavefront correction referred to as "refractive surgery technology," simply because this technology was around long before refractive surgeons ever started using it.


I'm sure you're right. I just never paid much attention to it until they started doing "laser retinal bounces."  I've only worked in medical optics. Have some of you worked in device optics like telescopes, microscopes, binoculars etc? Always thought such things would be interesting. 

I like what I do, but I'm in private practice in a rural area.  And sometimes...the stress of bleeds, trauma, glaucoma, tumors, corneal melt-downs etc. makes me long for just working with optics. 




> While wavefront-guided ablation certainly minimizes the wavefront aberrations traditionally produced by the refractive surgery, itself, such as spherical aberration, clinical studies have demonstrated that postoperative results are frequently no better than the patient's best corrected acuity prior to surgery.


Well said, and the good surgeons, at least the ones with whom I work, recognize that fact. 

You could also say that the "distortions (or at least complaints) of shape perfection" was why the surgeons started looking at wave front analysis more closely. Such complaints are expensive.




> I have a 25-year-old book from Mo Jalie that discusses these optical principles in detail.


I've only recently paid attention to this guy's stuff. Mo Jalie ain't your run-of-the-mill light bender. 

Respectfully,
dbracer

----------


## dbracer

> Hey drk,
> 
> I think you may have some pretty good questions here.  I just don't quite understand them -- not that I have the answers.
> 
> Could you expound a little? 
> 
> Respectfully,
> dbracer


drk,

Okay you don't have to address my question. These guys are clearing-up your points quite nicely for this rather dim wit. 

Respectfully,
dbracer

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## Darryl Meister

> Have some of you worked in device optics like telescopes, microscopes, binoculars etc? Alway thought such things would be interesting.


No. But I did sleep in a Holiday Inn Express last night. ;)

Seriously, though, I am reasonably familiar with telescope optics from a project I did for an astronomy course in college (knowing basic telescope optics was also required for my Master certification). And I've become very familiar with the application of adaptive optics for phenomena such as atmospheric turbulence over the past few years, as well as the application of aberrometry for higher-order ocular aberrations.




> Mo Jalie ain't your run-of-the-mill light bender.


He is a very friendly, well-spoken person though -- and probably one of the most knowledgeable folks in the field.

----------


## Andrew Weiss

> I've been measured on the iZon (aberrometer) machine, which indicated I have significant spherical aberration in my cornea (not surprising, since I had LASIK 5+ years ago and have noticed some aberration at night).  I'm hoping to try the Ophthonix lenses at some point (unfortunately, they "don't trust" the readings they get at Expo- so I have to make it to an office with the equipment)- just to see if there is any observable improvement in my night vision.


I'll be interested to hear what your experience is of wearing the lens.  A little real-world test group of one ;).

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## dbracer

Oh Boy,     I gets to find out something completely off the subject but I've always wanted to know.

Is Mo Jalie pronounced -- Moe *Jol'*ly   or   Moe zhau *li'* ??

I've alway said the latter, but just because I like it better.

Respectfull,
dbracer

----------

