Zeiss Individual vs. J&J Definity

[Darryl Meister]

I have heard testimonials.

I could provide you with literally hundreds and hundreds of written testimonials from wearers that would lead you to believe otherwise. I'm sure Pete could do the same for his products.

Come on Darryl, you are an extremely bringht individual. You are actually going to say that the one lens is much better than the other?

More to point, I would definitely say that a wearer could tell a difference between Gradal Individual and Definity (except perhaps a low-Add wearer who isn't particularly discriminating). Now, could a wearer tell the difference between XLGold and Definity? Maybe not. ;)

I understand that the Individual takes these variables into play, but I have to question will these variables have an effect?

Here are ray-traced plots of optical blur produced by a typical +2.00 Add progressive lens for:

1) Plano Rx
2) Moderate Minus Rx with Moderate Cyl

1 2

Note how the zones of clear vision are reduced and distorted as the prescription deviates from the "optimal Rx" of the Plano prescription (1). These semi-finished lenses use the same basic design in both cases, but the second wearer (2) obviously wouldn't enjoy the performance of the "ideal" design (1) because of the effects of oblique aberrations, toric errors, position-of-wear differences, and so on. A free-form lens with prescription optimization ensures that the lens maintains the optical performance of the "ideal" design, regardless of prescription, so that all wearers receive the same optimal performance.

Because all lenses take PD into play... Most PALs do have some changes with RXs.

Unfortunately, no semi-finished progressive lens can take the wearer's specific prescription into account. Consequently, semi-finished lenses can only be customized for broard categories of wearers. An average distance PD must also be assumed, which means that the near inset of the lens will be off for wearers with a wider or narrower PD (since wider PDs require greater insets, and vice versa).

I would never dare to question or oppose Darry's capabilities when it come to mathematics and optical formulas because, he is a master, and I could not even tell, if he would be wrong.

Yes, I know a lot of the "math," but it would be impossible to truly understand the optics of spectacle lenses -- much less lens design -- without a foundation in mathematics. It is also true that much of my work relies on mathematics and statistical analysis. However, you're mistakenly assuming (as you have in many threads) that my experience is limited to mathematics, which is far from the case. I have been intimately involved with this industry for fifteen years in a variety of capacities, including basic dispensing, laboratory work, technical services support, quality assurance, standards development, optical analysis, etcetera.

So, above mentioned "tendency" is based on "life long expierience" which lets you recognize and feel the back stage of the theater even before the play is on.

Believe it or not, I have a few years in this industry, myself, Chris. Besides, who's to say that you haven't been doing it all wrong this entire time? ;) Knowledge certainly isn't forced upon you in this industry, no matter how long you've been in it. I would encourage you to avoid seeing your "life long experience" as a reason to assume that you already know everything or have nothing else to learn.

[QDO1]

A pantoscoptic tilt should be adjusted at ALL times

#So hypothetically, based on the RX: R+6.00 -3.00 x45, Add+3.00, Measured height=24 FBR, DOC 34/34 NOC 32/32, into a Aviator with a B (overall height) frame measurement of 35 mm, a Pantoscopic tilt of 8 degrees.... What adjustment would you make? to be easy, lets say the minimum fitting height of the lens is 18mm - say a 1.6 Varilux Panamic for example.?

[QDO1]

"ideal" design, regardless of prescription, so that all wearers receive the same optimal performanc.

To add some balance to my posts I have to ask: Are you absoloutley sure that a + 6.00 - 3.00 X 45 Add +3.00 will get the same optimal performance as a -2.00 Ds with a 1.25 add?

[harry a saake]

I have to agree with Darryl on this subject. As an old timer myself in this business, over 40 years, i have run across many Chris Ryser types, with the negative thinking about new products. If we were to follow this to its conclusion, we would still be dispensing glass lenses, kryptoks, front grinds, etc.
The old timers also use to say this business was good, but you will never get rich from it, just have a steady job, also not true as i was to experience.
Time has shown that all of these innovations, as slight as they might appear at the time, has been the backbone of the progress that has been made and will continue to be the force that drives newer and newer products.
One of the scenarios i have noticed, especially after being on optiboard all these years, is how little is understood by the average optician, and more especailly when it comes to lens design. Therefore i have to conclude, how can you be complaining, whining or knocking something that you don,t even know much about.
Question: how many optiboarders have been to a lens design school, or taken courses in lens design, i know i have not.
In closing what i can say is thank god for people like Darryl, who can explain it to us.

[For-Life]

Darryl, but with the Definity and Individual both being freeform Atoric how would provided by the Zeiss Individual improve the performance? Basically, how is the design changed to improve that?

[Darryl Meister]

To add some balance to my posts I have to ask: Are you absoloutley sure that a + 6.00 - 3.00 X 45 Add +3.00 will get the same optimal performance as a -2.00 Ds with a 1.25 add?

By "Optimal Rx," I'm referring to the lens design for a given Add power. As you know from our previous discussions, a +3.00 Add must have significantly more unwanted astigmatism than a +1.00 Add.

A prescription optimization routine (at least SOLA's) minimizes the differences between the optical performance of the actual lens with the specified prescription and the optical performance of the target design with the "Optimal Rx" by adjusting the design of the progressive lens surface accordingly. While there will still be differences in performance between +6.00 -3.00 x 45 and -2.00 sph lenses, those differences will be relatively small (and considerably smaller than they would be without the prescription optimization).

Darryl, but with the Definity and Individual both being freeform Atoric how would provided by the Zeiss Individual improve the performance? Basically, how is the design changed to improve that?

Definity isn't atoric though, and doesn't currently include any prescription, design, or as-worn optimization / customization (you can refer to my earlier post in this thread regarding the differences between Gradal Individual and Definity). However, that's not to say that Essilor won't ever incorporate this kind of technology into the design, should they continue to offer it.

I should also add that the Gradal Individual lens isn't strictly "atoric," but rather employs a more general, complex surface that combines the optical performance of an atoric design with the actual progressive surface optics -- in addition to some other refinements.

I would encourage you to avoid seeing your "life long experience" as a reason to assume that you already know everything or have nothing else to learn.

By the way, Chris, I don't want to come across as though I'm picking on you about this. For all I know, you might spend every day trying to learn something new.

In closing what i can say is thank god for people like Darryl, who can explain it to us

Thanks for the kind words, Harry.

[For-Life]

Okay, I understood that the Definity was atoric

[Chris Ryser]

........................................... i have run across many Chris Ryser types, with the negative thinking about new products.

Just in order to defend my type ......................having made many inventions of working processes and new products and ideas in the optical field over the last 20 years that are being used on a daily basis from manufacturing to retail.

How can this type of humans species be only a negative thinker ? In my eyes this type is mentally way ahead of people that are just followers and do not question reality.

Maybe you should re-define above quote....................to state that some active types of the old timers are still way ahead of passive professionals, that eat anything without questioning because big corporation advertising tells them so.

If we were to follow this to its conclusion, we would still be dispensing glass lenses, kryptoks, front grinds, etc.

Well well well well.........................what have you done, Harry, to get the industry out of your above quoted Hell ?

[Chris Ryser]

[QUOTE=Darryl Meister]
By the way, Chris, I don't want to come across as though I'm picking on you about this. For all I know, you might spend every day trying to learn something new.
[QUOTE]

Darryl, I dont mind being picked on..................gives me chance to pick back.

I never try to learn something new every day.....................I am forced to do it.

[Darryl Meister]

How can this type of humans species be only a negative thinker ? In my eyes this type is mentally way ahead of people that are just followers and do not question reality...to state that some active types of the old timers are still way ahead of passive professionals, that eat anything without questioning because big corporation advertising tells them so

But, Chris, you routinely make remarks belittling progress in lens design, and have in fact insinuated that most people would be better off in conventional bifocals (invented in the 1780s). Surely your implication is not that you are all for new technology, as long as it involves a product you sell? After all, the industry was also doing just fine without plastic tints and in-office lens coatings 230 years ago.

[Robert Martellaro]

Gradal Individual uses a traditional toric back surface and a free-form progressive front surface.

The add is on the front surface? Are there any free-form PAL's with the full add on the back? Obviously it needs to be one that is free-form on the back surface. My understanding was that both sides of the Zeiss lens were surfaced and I assumed they were both direct surfaced or free-form. Looks like I need to take a closer look at how this new technology is implemented.

Regards,

[harry a saake]

Chris, what have i done, nothing, and i,m not ashamed to admit i am not bright enough to make the kind of changes that people like Darryl can routinely do.
...As far as what hell, what hell are we in, i simply stated that if everyone had your views we would be back in the stone ages.
.....your statement on the bottom of every thread you send is the problem, you dont want the established order changed as don,t a lot of others that do not want anything changed they cannot comprehend.
...Your statement you NEVER try to learn anything new, why not, and BTW who,s forcing you to learn. In the US we have an answer for that malady, its called early retirement

[Darryl Meister]

The add is on the front surface? Are there any free-form PAL's with the full add on the back?... My understanding was that both sides of the Zeiss lens were surfaced and I assumed they were both direct surfaced or free-form.

The implementation varies from manufacturer to manufacturer. For example, AO Easy HD and SOLAOne HD are made by free-form generating both the progressive optics and the prescription curves together on the back surface (the front surface is cast). Zeiss Gradal Individual and Short i are made by free-form generating the progressive optics on the front surface, while the prescription curves are generated using conventional equipment on the back.

[harry a saake]

Darryl, does this mean that every single lens is actually ground on the front and then polished, and if so how do they accomplish that on a production basis.

[Darryl Meister]

Darryl, does this mean that every single lens is actually ground on the front and then polished

With Gradal Individual, each lens is actually generated twice. The front surface is generated and polished using CNC free-form generators and CNC free-form polishers, while the back is generated, fined, and polished using traditional generators and cylinder machines. With SOLA HD (High Definition) lenses, the front surface is already cast to the desired nominal base curve, and the back of each lens is generated and polished using CNC free-form generators and CNC free-form polishers.

if so how do they accomplish that on a production basis.

A lot of time and $$$. ;)

[Chris Ryser]

Surely your implication is not that you are all for new technology, as long as it involves a product you sell?

After all, the industry was also doing just fine without plastic tints and in-office lens coatings 230 years ago.

Here we go again................ping pong........back and forth.

Of course you are right, I am interested in new technology specially when I developed it myself, ........................if I sell it or not........it is there and I am taking the credit.

The industry has been doing fine for all this time for 230 years as you state.
However for 205 of these 230 years the trade was a very labour intensive industry improving the products as it went along with time. The ultimate goal of the industry for this time, was to provide the best vision aids possible for the particular time segment in its history.The last main invention and development was by SL (now ESSILOR) by bringing the Varliux lens on the market in 1955.

The principle of this lens was (and still stands)to replace multifocal lenses by providing a progressive power flow over from distance to near vision without any visible lines and the image jump old style bifocals were providing.

However this could and still can only be achieved by having areas of distortion on the front surface, also the size of the reading area becomes smaller as the reading addition increases. Including some alterations and improvements by one or the other company the original principle still stands.

All the large optical corporations now treat the progressive lens as their crown jewels and create super advertising and hype to convert as many people as possibe to purchase these products which are their most profitable items on the program of products.

And one more thing Darryl, ............whenever the company you defend and work for, comes up with a progressive that has ZERO distortion throughout the whole lens area it merits a Nobel price and all critical comments should be prohibited.

[Darryl Meister]

However for 205 of these 230 years the trade was a very labour intensive industry improving the products as it went along with time. The ultimate goal of the industry for this time, was to provide the best vision aids possible for the particular time segment in its history.

Chris, the goals of this industry -- and any other industry for that matter -- haven't changed: produce a quality product, generate a consumer demand, improve production efficiency, minimize overhead, maximize profit, and so on.

The principle of this lens was (and still stands)to replace multifocal lenses by providing a progressive power flow over from distance to near vision without any visible lines and the image jump old style bifocals were providing.

Actually, the principle was to replace the eye's natural accommodation, once it has been lost to presbyopia.

All the large optical corporations now treat the progressive lens as their crown jewels and create super advertising and hype to convert as many people as possibe to purchase these products which are their most profitable items on the program of products.

Actually, in terms of percentage of return, the tints and in-office coatings you sell are by for more profitable than progressive lenses.

And one more thing Darryl, ............whenever the company you defend and work for, comes up with a progressive that has ZERO distortion throughout the whole lens area it merits a Nobel price and all critical comments should be prohibited.

1. I'm not defending my company. I'm defending the entire industry against your misguided attempt to keep everyone in flat-top bifocals. On second thought, this week I'm actually defending the entire industry against your misguided attempt at convincing everyone that all progressive lenses are exactly the same because they all have some degree of "distortion." The bifocal argument was last week. ;)

2. Until they invent a flat-top bifocal that produces no image jump, no scotoma, a full depth of field, and still looks good, you should stop assuming that the distortion in progressive lenses is the only factor worth considering here.

[Chris Ryser]

On second thought, this week I'm actually defending the entire industry against your misguided attempt at convincing everyone that all progressive lenses are exactly the same because they all have some degree of "distortion."

Darryl.....................you have to be congratulated of having taken the old corporative armour out, to defend the entire industry against my misguided attempts.

I have never said that all progressives exactly the same...........but i have said they are all the same in principle with some variations. They also do have some degree of distortion, your own example posted, does show some of it. When you look at the outlay of the finished lens, as per your posted picture below, the non distorted area does seem pretty small at least to me, the old misguided critic.

Note how the zones of clear vision are reduced and distorted as the prescription deviates from the "optimal Rx" of the Plano prescription

Maybe I am not so misguided after all. Furthermore I have also never tried to discourage anybody from purchasing or selling progressive lenses wherever they are the right choice, but I have always said that optical retailers should be aware that there are many cases where progressives are not the best choice.

However the industry you are officially defending is handing out non adapt warranties therefore tempting the retailers to go ahead and sell, sell, sell them also to patients that are much less than ideal cases to adapt to these types of lenses, out of many various reasons. The retailer can always use the warranty to save his reputation and or lack of judgement.

[QDO1]

For-life neglected to answer my question earlier in the thread, to be fair to Daryl - he did answer mine....


Quote:
Originally Posted by For-Life
A pantoscoptic tilt should be adjusted at ALL times

#So hypothetically, based on the RX: R+6.00 -3.00 x45, Add+3.00, Measured height=24 FBR, DOC 34/34 NOC 32/32, into a Aviator with a B (overall height) frame measurement of 35 mm, a Pantoscopic tilt of 8 degrees.... What adjustment would you make? to be easy, lets say the minimum fitting height of the lens is 18mm - say a 1.6 Varilux Panamic for example.?
__________________
King
_____________________________________________

[Darryl Meister]

to defend the entire industry against my misguided attempts

Well, no one else stepped in. ;)

Maybe I am not so misguided after all.

Unfortunately, Yes, you are. ;)

The plot you are referring to represents the zones of "perfectly clear" vision in order to more clearly distinguish the differences made by prescription power errors between designs. This plot does not represent the zones of "usable" vision in a progressive lens, as any progressive lens wearer could tell you.

Furthermore, this particular type of plot could not effectively illustrate the optical limitations of a flat-top bifocal, which include a significant jump in image size and location over a rather large region of the surface, significant blur and scotoma (blind area) around the segment margin, and loss of intermediate utility -- in addition to any prescription power errors in the major (distance) portion.

You are also trying to convince people that any two progressive lens designs -- such as the two shown below (typical hard and soft progressives) -- will perform exactly the same for the wearer.



And, quite often, you are simply misinformed. For example:

The last main invention and development was by SL (now ESSILOR) by bringing the Varliux lens on the market in 1955... The ultimate goal of the industry for this time, was to provide the best vision aids possible for the particular time segment in its history.

For starters, the progressive lens was first conceived in 1907 (by Owen Aves). Improved designs were patented in 1909. But Essel did invent a new class of progressive lenses, which were first released in 1959, and certainly the first commercially successful progressive lenses in Europe (Omnifocal had them beat by a year or two here in the US). Secondly, lens manufacturers have always tried to improve upon and differentiate their premium products from competitors, including corrected curve lenses, low-dispersion flat-top bifocals, cataract lens designs, progressive lenses, and so on.

Furthermore I have also never tried to discourage anybody from purchasing or selling progressive lenses wherever they are the right choice

You have repeatedly railed against lens manufacturers as the perpetrators of some vast dark conspiracy (e.g., referring to Essilor as the "Evil Empire"), touted flat-top bifocals as indisputably superior optically to progressive lenses, accused all progressive lenses of being "exactly the same" on several occasions (including this very thread), and so on.

Chris, if you want to sell only flat-top bifocals (and I didn't think you sold lenses at all), that's certainly your prerogative. And eyecare professionals can purchase the multifocal of their choice, as well (virtually every major progressive lens manufacturer also makes flat-tops).

But keep in mind that progressives do have their advantages, both optically and cosmetically. Furthermore, they are also more profitable for the eyecare professional. Many -- if not most -- consumers appreciate premium products, and see legitimate "value" in progressive lenses. Eyecare professionals are not going to grow their business selling only antiquated flat-top bifocals, though -- Yes -- these lenses have their place.

[Darryl Meister]

Chris, to the extent that you are trying to educate eyecare professionals on optics and lenses, whether your statements are entirely accurate or not, I have no issue with your post. You have a great deal of valuable experience in this industry, which is useful to the entire 'Board. However, several of your posts often seem to suggest an underlying bitterness with corporations -- and lens manufacturers, in particular -- for reasons that you have never really made entirely clear.

[QDO1]

I have never said that all progressives exactly the same...........but i have said they are all the same in principle with some variations. They also do have some degree of distortion, your own example posted, does show some of it. When you look at the outlay of the finished lens, as per your posted picture below, the non distorted area does seem pretty small at least to me, the old misguided critic.

Chris - I think you are out of order

What you are saying is like this (Im making another car analogy):
Bicycles are the best form of transport, cars are all the same, we used to have horses years ago. Ford motorcars have a vendetta to get rid of cycles, because they want to sell you cars, they keep upgrading thier car, hell they even put windows and a roof on it, but Im not worried, because bicycles are the best. Dammit GM have put a roof on a car - they are just recycling the same old thing and re-packaging it

many years later, cars still have 4 wheels, engines brakes and steeringwheels, but you must agree - they are a long way from the original ones made. And we still have bicycles. What form of transport is the best - neither - in the desert a horse, in delli - a cycle, in urban america a car

We have many different patients, and as you know each dispense for a presbyope is a comprimise. We choose from a range of lenses the best comprimise - sometimes a D35, or progressive, or single vision - they are all right, for the right patient

To slag off manufacturers for pushing the envelope of whats possible, is like complaining that they put roofs on cars. Out of preference I would fit a varilux comfort over a varilux 1, why - because it factually is a much better lens. For many years we have had the same basic surfacing teqniques available to us. Now with the Advent of freeform, and computers fast enought to develop lenses and work freeform, and the vision of the R&D departments, we can break away from the "one design fits everyone" philosopy and work with patients as individuals

why not for a period of say 6 months, leave your skeptical hat outside, Bone up on the technology, learn why the R&D departments do what they are doing (perhaps even go visit one)- you might be surprised, what actually is possible

[Chris Ryser]

Chris - I think you are out of order

I don't think so. Darryl loves to pick on me..........and I can get him going into an attack mood. We have had periodic differences and then we lay down our arms and become peaceful again. So dont get exited the storm will blow over.

[QDO1]

I don't think so. Darryl loves to pick on me..........and I can get him going into an attack mood. We have had periodic differences and then we lay down our arms and become peaceful again. So dont get exited the storm will blow over.

I wasnt talking about Daryl, I was talking about you

[Darryl Meister]

Chris and I ensure that OptiBoard never gets too dull. ;)