Comparing individual single vision lenses

[Nikolay Angelov]

Hello everybody,

I love the idea of the personalized s.v. lenses but have one central question.
Namely how to objectively compare products from different manufacturers?
As i see it, there are two possibilities:

1. The optimizations are simple and the lenses are now possible thanks to the advances in manufacturing technology.
In that case i would like the manufacturers to give us the math formulas used to optimize the lenses as they are nothing secret.

2. The optimizations are innovative and the manufacturers have applied or been granted patents on them.
After all it would be common sense to patent such new non-obvious optimization technology.
In that case could the manufacturers point to the pattens involved so we could read about the the different lenses and compare them objectively.

I think the marketing simplifications for the end consumers are good as long as they are not deceiving. After all they help the buyer choose a suitable product without requiring him to become an optician.

However we as professionals need to know the objective merits and mathematics behind the new lenses.

I would hate this new product segment to become "foggy" and unclear as the progressives one has become.
We need the mathematics and the hard facts of these lenses.


PS: Originally i wanted to know the difference between the "Zeiss Individual SV" and "Rodenstock Impression Mono" :p .

PS2: OptiBoard rocks. I have already learned a great deal form all of you (Thanks for helping me take the Optician exams :) ).

[Uilleann]

In short: There is no realistic way for the average dispenser to do this. Not at least to the level of detail and information I believe you're hoping to find.

I hate to say it, but I further believe that are probably more likely to be influenced by the pricing, business model, or special rebate offers of a given manufacturer right now, than by any large difference in overall lens quality or optical benefit between them.

As for the 'foggy areas'...too late already IMHO. As you are no doubt aware, EVERY lens manufacturer on the planet uses marketing to try and gain a competitive advantage against their peers. I would hesitate myself to go so far as to say that they're lying about their particular products or technology. But I WOULD say that there is a very healthy dose of "working REALLY hard to make the data appear to support this claim or that claim we made about X lens style. It's the industry game, and it certainly makes things difficult for us don't it?!

If you do find out anything along the lines you're searching for, do let us know?

All the best!

Bri~

[optical24/7]

I agree with Bri~; There's very little difference in modern lens designs. All players in the field are racing for the same *supreme optical performance*. There's nothing revolutionary between them because they are all utilizing current knowledge and fabrication capabilities, they are racing towards the same goal.

Imho, You can put/switch most any current patient in a top design from whomever, and have great results, especially FF and DS lenses that offer atoric correction for cly Rx's. Keeping patients in their current designs is a non-issue today.

[Nikolay Angelov]

Patents do exist,
Here are some examples taken from "Ophthalmic lenses and Dispensing" 3rd edition by Mo Jalie:


"References:
...
2. UK Patent 2030722 1980/US Patent 4289387 1981. Ophthalmic spectacle lenses having hyperbolic surfaces.
3. US Patent 5083859 1992. Ophthalmic spectacle lenses having hyperbolic surfaces.
4. Hoya Corporation. Aspheric Eyeglass Lens International Patent application 1997; PCT/JP97/00054
...
"


The patent application from Hoya is for their Nulux aspheric lens - the math behind the lens is in the patent and explained partialy in the textbook.
There are patents covering the progressives but we have to start the search for science somewhere :)

I hope that Darryl Meister would be kind enough to inform us on the relevant patents concerning the "Zeiss Individual SV".
Georg Mayer could help us with information on the relevant patents concerning the "Rodenstock Impression Mono".
I am sure many OptiBorders would greatly appreciate their help in this.

Do we have to pay patent lawyers just to find technical information about the products we love and use :p ?!?

[Uilleann]

Patents have existed for centuries. Doesn't mean you'll learn very much trying to read them. Think of cars, or maybe airplanes...heck even rockets! None of them will deviate much from a standard design: A car has to roll, therefore they all have wheels. A plane has to fly, ergo the wings. A rocket much be able to fly fast so a ballistic shape and fins allows for speed and control.

Optical lenses, whether they're SV progressive or any other flavor are all aiming for the exact same goal - perfect vision for the end user. And since we all know that the optical performance of every material known (and used) by man to be less than perfect, we just have to use what we have. That also means using the current level of technology, computing power and machining capabilities. I doubt very much that you'll ever see a single player bolt out ahead of anyone else with a game changing breakthrough or truly revolutionary technology.

It's fun to hope though right?! :)

BEST!

[opticianbart]

I have a pair of the Zeiss Individuals and as far as I can tell they are the clearest SV lenses I've ever gotten my hands on. Although at the price tag they currently have they're waaaaaaaaay out of my price range! The only reason I was able to get a pair was when our rep wanted us to try them, and I'm certainly glad he did because I think they're great!

P.S. - Kudos, you used ergo in a sentence, can you make a word of the day thread? :)

A plane has to fly, ergo the wings.

[Nikolay Angelov]

I think we can learn a lot form the patents, just as an aerospace engineer can learn from the patents in his field.

With the theory and math of the lenses we can model their performance, recommend and sell them for justified big $ :D
http://www.lambdares.com/software_products/oslo/oslo/

Should we advice our clients to purchase a product (n) times more expensive than the current ones, based on marketing claims and "Data on file" ?!?
This week i will request the technical and patent information from the manufacturers and see how it goes.
I hope they will provide us with the info readily :)
Hey if i have some free time i will search the online patent databases as well

...
Watto: How are this lenses better than the current ones?
Qui-Gon Jinn: I have twenty thousand pages of marketing claims.
Watto: Marketing claims? Marketing claims are no good out here. I need something more real.
Qui-Gon Jinn: I don't have anything else...
[waves hand]
Qui-Gon Jinn: But marketing claims will do fine.
Watto: No, they won't-a.
[Qui-Gon waves his hand more firmly]
Qui-Gon Jinn: Marketing claims will do fine.
Watto: No, they won't-a. What? You think you're some kind of Jedi, waving your hand around like that? I'm a Optician. Mind tricks don't work on me. Only scientific evidence. No Scientific evidence, no sales, no deal!

[Barry Santini]

Human Beings are NOT telescopes, binoculars or cameras. Therefore, "data on file" does not and will not reveal the individual aberration weightings a specific design uses, nor will it reveal the intent of these weightings and their effects on client perceptiual satisfaction.

What works, works. Take my word for it (as I do from the lens designers).

B

[Nikolay Angelov]

Mr. Santini that is precisely what i want to do: take the word of the lens designers not the marketing people.

Now can we stop with the political and philosophical mumbo-jumbo. Please.

If you have technical information (mathematics, optimizations done, patents) on the individual s.v. lenses share it and lets discuss it. If you want to discus something else (lens politics, marketing, ..., the weather) please start another thread.

What i am after is:
Lens "A" is covered by patents 1, 2 and three. Or here is what optimizations are done to the lens: 1, 2 and three. Or call/fax this department for the information you seek. Or contact that department for the "Data on file". Etc.

Without solid data all the discussions would be useless for the problem at hand.

Sorry if i have come forth too directly but there are already a lot of posts containing zero technical information or advice on how to get info.:)

[WFruit]

Here is a great place to start for technical inforamtion: http://www.optiboard.com/forums/foru...File-Directory

Most Lens manufacturers have contact information on their websites that you can use to get further information specific to their lenses. Some even have the technical information you are looking for on their site as well.

[Nikolay Angelov]

Thanks,
I've read all that plus the pdf's from
http://www.personalizedlens.com/ProfTechnicalInfo.aspx

and

http://www.rodenstock.ca/index.php/p...tent/downloads

and

http://www.isoptik.com/forum/forum_topics.asp?FID=15

and everything from

http://www.opticampus.com/
More please :cheers: :D

[AngeHamm]

I have a pair of the Zeiss Individuals and as far as I can tell they are the clearest SV lenses I've ever gotten my hands on. Although at the price tag they currently have they're waaaaaaaaay out of my price range! The only reason I was able to get a pair was when our rep wanted us to try them, and I'm certainly glad he did because I think they're great!

P.S. - Kudos, you used ergo in a sentence, can you make a word of the day thread? :)

I completely agree. I have two pair each of Zeiss Individual and Essilor SV360. Both show a far wider area of center focus in my -7ish lenses than standard aspheric 1.67, but the Zeiss lenses are ENORMOUSLY better than the Essilor.

[Uilleann]

...that is precisely what i want to do: take the word of the lens designers not the marketing people...

Methinks you're setting yourself up for epic failure in thy quest my liege.

Lens designers aren't paid to talk to the general public, nor even to ecp's. They're paid to design lenses. Now their respective marketing departments on the other hand...

There is a wealth of information available all over the web pertaining to lenses, and general design concepts. But I would make the absurd assumption, that if you truly want to understand what makes a lens perform in a given manner, your best chance of that is to take your masters or PhD in advanced optics, join that respective company's design team, and learn it all from the inside.

Otherwise, I doubt you'll get much farther than you have already. Phone calls would, I expect, only get you many polite rejections as what (I think) you're asking for equates to VERY sensitive company trade secrets. Think they aren't gonna do everything they can to protect that? Think again.

[Nikolay Angelov]

OK searched WIPO and found gold :D
There are MANY patents with TONS of information on the topic.

This is SMALL sample of Rodenstock's patents and/or patent applications.
Hmmm Looks like Rodenstock is a bit ahead looking at their patents/applications and the dates of applications :)

(WO 2005/019904) INDIVIDUAL SINGLE VISION SPECTACLES

(WO 2008/089999) METHOD FOR OPTIMISING A SPECTACLE LENS

(WO 2010/054817) OPTIMIZATION AND PRODUCTION OF AN EYEGLASS LENS FOR CORRECTING AN ASTIGMATIC REFRACTION

(WO 2009/083218) METHOD FOR CALCULATING AND OPTIMIZING A PAIR OF EYEGLASSES IN CONSIDERATION OF BINOCULAR PROPERTIES

(WO 2007/062784) METHOD FOR CALCULATION OF THE MAGNIFICATION AND/OR DISTORTION AND METHOD FOR PRODUCTION OF A SPECTACLE LENS WITH LOW MAGNIFICATION AND/OR DISTORTION

And some Zeiss patents :

Curious about the Zeiss:) wavefront optimizations ... read:

(WO 2010/017938) SYSTEM AND METHOD FOR PRESCRIPTION OF VISUAL AIDS
In one aspect, the invention features a method for determining an eyeglass prescription for an eye. The method includes obtaining a measurement of a wavefront indicative of the refractive properties of the eye, establishing an optimization space corresponding to a plurality of possible prescriptions for the eye, determining a value for a merit function for each of the possible prescriptions in the optimization space, where the merit function value corresponds to a visual function of the eye when corrected using the corresponding possible prescription, generating a representation of the merit function values, and outputting the representation to an eye care professional.


Look at what AR Zeiss is developing ... Nice :)
(WO 2010/025829) EYEGLASS LENS HAVING A COLOR-NEUTRAL ANTIREFLECTIVE COATING AND METHOD FOR THE PRODUCTION THEREOF


Here is the search engine, have fun:cheers:
http://www.wipo.int/pctdb/en/


If you are interested the actual texts are online. Google is Your friend ;).

Uilleann thanks for the encouragement

AngeHamm anecdotal evidence means nothing ... scientifically speaking :) .

People Please stay on topic or start another thread.

PS: You know you love your job when you are doing it in 1:00 in the morning ... in your free time.

PS2: Why people patent stuff in excruciating technical details? If they do not their competitors will and they will have to pay Them royalties instead of the other way around.
Ahem ... Essilor (Anti slip coating) patent/application ahemm:

(WO 2010/055261) METHOD FOR TREATING, BY MEANS OF AN ADHESIVE FILM, AN OPTICAL LENS COMPRISING A DIRT-REPELLANT COATING FOR THE EDGING THEREOF

[Darryl Meister]

I hope that Darryl Meister would be kind enough to inform us on the relevant patents concerning the "Zeiss Individual SV".

Carl Zeiss Vision's (ZEISS/SOLA/AO) intellectual property for single vision lens design goes back many decades. Of course, the first corrected curve (Punktal) and aspheric (Katral) spectacle lenses were invented at Carl Zeiss Optical. But, over the years, several advancements have been made in aspheric and atoric single vision lenses, including lenses described by US Patent 3,960,442 (granted to AO in 1976) and US Patent 6,305,800 (granted to SOLA in 2001), among many others.

The technology that really served as the basis for modern ZEISS single vision lenses, however, which utilize real-time optical optimization in conjunction with a free-form manufacturing platform, was first described by US Patent 4,613,217 (granted to ZEISS in 1986). This patent described a lens with a complex or "free-form" surface that was optically optimized for the position of wear. Of course, the technology has evolved a great deal over the past 30 years. And several other relevant patents have been granted since then.

Best regards,
Darryl

[DCrespo]

Hi,

Being a lens designer myself, this is what I think that all personalized SV lenses try to do in one way or another:
- The main aberrations that affect a SV ophthalmic lens, and that can be reasonably corrected with free-form technology are oblique aberrations: oblique unwanted astigmatism and oblique power error. (The other single aberration that is very important would be transverse chromatic aberration, but there is not much that free-form technology can do to imporve this, this needs to be imporved through new materials).
- In a traditional lens, oblique aberrations will make that visual acuity drops when you are looking through the sides of the lens, the lens is only perfect in the center. This effect depends strongly on the combination of prescription and front curve.
- Traditionally this has meant that a particular base curve must be selected for each prescription (remember Tscherning's ellipses?).
- In the case of lenses with a high wrap, there is also a prismatic effect induced by the wrap angle that needs to be corrected.
- But a free-form surface can be modified point-by-point to compensate oblique aberrations (and of course, the prismatic effect induced by the wrap). Therefore, it expands the area in the lens where we have good visual acuity.
- This also implies that you have much more freedom to select any base curve for any prescription, because oblique aberrations are no longer a limiting factor. There are still limits, but these limits are much broader than with traditional lenses.
- The particular way to reduce aberrations and compensate prism can change from one designer to another, but we are all looking for the same.
- Some designers have claimed (like the Izone lenses did at the beginning) to be compensating higher order aberrations like coma. It is not possible to reasonably correct high order aberrations of the eye with an ophthalmic lense for a reasonably wild field of view, so these claims should be considered just as marketing distractions.

[Darryl Meister]

In a traditional lens, oblique aberrations will make that visual acuity drops when you are looking through the sides of the lens, the lens is only perfect in the center. This effect depends strongly on the combination of prescription and front curve

Additionally, oblique astigmatism is introduced through the center of traditional lenses due to pantoscopic and wrap lens tilt. This error will be proportional to the power of the lens and the magnitude of the lens tilt. A fully optically optimized lens will compensate for this effect.

You can read about some of the technical details of ZEISS Individual Single Vision in the Individual Single Vision White Paper, now available online.

Best regards,
Darryl

[Barry Santini]

Additionally, oblique astigmatism is introduced through the center of traditional lenses due to pantoscopic and wrap lens tilt. This error will be proportional to the power of the lens and the magnitude of the lens tilt. A fully optically optimized lens will compensate for this effect.

You can read about some of the technical details of ZEISS Individual Single Vision in the Individual Single Vision White Paper, now available online.


Best regards,
Darryl

Darryl,

Regarding the points you make above, I have some continued confusion I hope you can clear up.

If one fits a best-form, SV spherical lenses optimally, that is, on PD and with the OC displaced vertically to compensate for pantoscopic tilt, and, let's assume, as a conventional vertex distance of 13mm -

Shouldn't the sectional-area of the lens, intersected by the axial gaze, be assumed to enjoy excellent overall correction (especially for marginal astigmatism), as long as the semi-field of view angle is between 10-15 degrees from the OC?

I can only assume that what POW compensated, SV FF lense do is 're-weight" the section of the lens intersected by the central gaze, and more completely optimize it for the POW values supplied. With respect to this central gaze, most non-ff lenses, properly fitted, should deliver excellent optics for what range of pantoscopic tilts and spherical powers?

Thanks in advance.

Barry

[Darryl Meister]

If one fits a best-form, SV spherical lenses optimally, that is, on PD and with the OC displaced vertically to compensate for pantoscopic tilt, and, let's assume, as a conventional vertex distance of 13mm... Shouldn't the sectional-area of the lens...

IF the lens has a sphere power that corresponds to the optimal sphere power of the base curve or lens design and IF the lens has no cylinder power and IF the lens has no wrap tilt and IF the optical center has been positioned below the line of sight to compensate for pantoscopic tilt then, yes, a traditional lens will deliver good optical performance. But this is rarely the case in practice.

Of course, many jobs with traditional lenses will come pretty close, delivering acceptable vision to many wearers. The real benefit of customized lenses, in my opinion, is the ability to offer every wearer a lens that will deliver the best optical performance possible, regardless of his or her specific prescription requirements or frame fitting characteristics. Obviously, some wearers will enjoy more of a benefit than others.

Best regards,
Darryl

[Barry Santini]

Thank you. That's it!

B

[Nikolay Angelov]

Thank you for the help Mr. Meister :)

I have found additional patents/applications on the topic, but it was a busy week without much time to read them . I will read as much as i can during the weekend and post the list with the relevant information.

Textbooks covering the topic, more patent/applications and technical information are more then welcome so keep posting everyone :)

Here is a link for one of the patents Mr. Darryl Meister referred to:
Spectacle lens having astigmatic power - Patent 4613217


PS: The more i read on the topic the more i like these lenses.
We sold our first Zeiss Individual SV this week :) and our medium prescription colleague will be trying the Impression Mono hopefully soon :)
PS2: Optical reading + cold bear + beach = great weekend :cheers: :D

[xiaowei]

Hi,

Being a lens designer myself, this is what I think that all personalized SV lenses try to do in one way or another:
...
- But a free-form surface can be modified point-by-point to compensate oblique aberrations (and of course, the prismatic effect induced by the wrap). Therefore, it expands the area in the lens where we have good visual acuity.
- This also implies that you have much more freedom to select any base curve for any prescription, because oblique aberrations are no longer a limiting factor. There are still limits, but these limits are much broader than with traditional lenses.
..

Hi DCrespo, sorry for my late return to this forum and thread, but I think your statement requires some clarification:
With FF technology you can - in principle - really point-by-point compensate oblique aberrations, however this will generally NOT lead to a continuous surface!
This is a mathematical not a technical limitation, or in other words, the "PAL dilemma" that is so nicely illustrated by the "elephants trunk" analogy: When you try to bend the trunk so that curvature increases both along and perpendicular this works only along one "umbillc" line, while "wrinkles" must appear in all other areas.

[xiaowei]

Look at what AR Zeiss is developing ... Nice :)
...

(WO 2010/025829) EYEGLASS LENS HAVING A COLOR-NEUTRAL ANTIREFLECTIVE COATING AND METHOD FOR THE PRODUCTION THEREOF

...

Hi Nikolay, thanks

Sorry, somewhat OT, but interesting news for me, some time ago, when we had a new coating plant installed in our company, I had an interesting discussion with the company experts(?) and I also mentioned the so-called color-neutral AR that now some companies in the eyeglass busyness try to sell, which led to some amusement by the very same experts, because they also said it could not be done.

I tried to explain to them, that at least for a given spectrum of incident light, "white" appearance can always be achieved, even if the AR spectral response is not really flat, because of the way our eyes work. (On your TV, when it shows white, there are also actually three more ore less distinct RGB peaks)

Nice and reassuring to know that Zeiss seems to actually have done that and also improved as far as possible WRT varying incident light.

[Darryl Meister]

With FF technology you can - in principle - really point-by-point compensate oblique aberrations, however this will generally NOT lead to a continuous surface!

This is very true, but we should clarify that the goal of optical optimization is to find a continuous surface that comes as close as possible to delivering the ideal sphere and cylinder power corrections at every point across the lens. So, numerical optimization techniques using bivariate splines are utilized to manipulate a continuous surface repeatedly, until we can find the "best" continuous surface that minimizes optical aberrations as much as possible, much like in modern progressive lens design.

Best regards,
Darryl