Lets get this straight: Wavefront spectacle lenses

[chip anderson]

Where did any of us ever get the idea that "improvements in technology" were to "provide better vision?" Most "improvements in technology" are to "Attract a higher market share or market value, period." Even Der. Miester has told you that the purpose of aspheric technology is to "more nearly mimic corrective curve lenses." Logicly this means that corrected curve lenses are better but they are older technology made of older materials.

Perhaps it is time to go back to "corrected curve lenses." People saw very well out of lots of old designs, Ziess Puctal, B&L (trade name escapes me at the moment), Contintal had one, Modern Optics had several.

New = Most recent. Best=Most applicable for the job.
New does not equal better, much less best. Sometimes better means better than the piece of junk we had yesterday.

Chip

[fjpod]

Perhaps it is time to go back to "corrected curve lenses." People saw very well out of lots of old designs, Ziess Puctal, B&L (trade name escapes me at the moment), Contintal had one, Modern Optics had several.

New = Most recent. Best=Most applicable for the job.
New does not equal better, much less best. Sometimes better means better than the piece of junk we had yesterday.

Chip

Was the B&L called Orthagon?

[mirage2k2]

Great analogy Darryl! :D

I've looked at Finalite but my optician only deals with nikon and essilor - I looked at the SeeMax which could be great for me but the ABBE is 32! Although the overall vision might be better I'll still have the color seperation (which I see almost on the OC!) as a result of +5 base out prism. Incidentally, I'm seeing my optician in an hour to discuss the options:)

Aren't some 1.67s 36 ABBE?

Anyway, since there is all this new technology happening, wouldn't it be good to research the use of mixed index material? Thanks to your help, I now understand that none of the new lens designs can reduce chromatic aberrations - the problem is in the material and not in the design! So, is there any research being done for a mixed index material? I'm guessing that for a plus lense the high index would be in the OC and then the index would reduce towards the periphery ... and then some fancy aspheric curve would deal with the vision in the periphery?

[Darryl Meister]

Logicly this means that corrected curve lenses are better but they are older technology made of older materials.

Optically, you're exactly right: Aspherics aren't any better -- at least until you get into cataract lenses, which aren't especially common anymore. But, cosmetically, aspherics are thinner, flatter, and lighter in weight -- with less eye magnification.

Was the B&L called Orthagon?

Orthogon. Very close.

[Darryl Meister]

By the way, for those who are interested in this sort of stuff (all four of you ;))...

AO's was the Tillyer
B&L's was the Orthogon
Zeiss's was the Punktal
Shuron's was the Widesite
Continentals's was the Kurova
Univis's was the Best Form
Titmus's was the Normalsite

[mirage2k2]

Where did any of us ever get the idea that "improvements in technology" were to "provide better vision?" Most "improvements in technology" are to "Attract a higher market share or market value, period." Even Der. Miester has told you that the purpose of aspheric technology is to "more nearly mimic corrective curve lenses." Logicly this means that corrected curve lenses are better but they are older technology made of older materials.

But the aspherics look great! These days it has almost become unacceptable to walk the streets with milk bottles for glasses!!! People want to look good as well as see good! I looked at my wedding photos the other day - my glasses were almost as big as my face and my eyes looked huge!!! I preferred the vision in my best form lenses but with my new aspherics I look normal again:D

[rinselberg]

Aren't some 1.67s 36 ABBE?

Hoya 1.70 with Abbe 36 ...
http://www.hoyaopticallabs.com/170_eyry.htm

[fjpod]

By the way, for those who are interested in this sort of stuff (all four of you ;))...

AO's was the Tillyer
B&L's was the Orthogon
Zeiss's was the Punktal
Shuron's was the Widesite
Continentals's was the Kurova
Univis's was the Best Form
Titmus's was the Normalsite

Good grief. I remember having to memorize all these for the national boards back then.

[mirage2k2]

I've just figured out how to quote so I thought I'd quote myself :D

Anyway, since there is all this new technology happening, wouldn't it be good to research the use of mixed index material? Thanks to your help, I now understand that none of the new lens designs can reduce chromatic aberrations - the problem is in the material and not in the design! So, is there any research being done for a mixed index material? I'm guessing that for a plus lense the high index would be in the OC and then the index would reduce towards the periphery ... and then some fancy aspheric curve would deal with the vision in the periphery?

Any takers?

[Darryl Meister]

Hoya 1.70 with Abbe 36 ...

Here is a pretty comprehensive list.

is there any research being done for a mixed index material?

What you're referring to is known as a gradient index lens (or GRIN), and it would be relatively expensive to utilize for a spectacle lens -- at least for the advantages it would provide.

[mirage2k2]

thanks, great link:cheers: . Are gradient index lenses something you see as becoming affordable, i.e. do you see a use for them in specs in the future - all things get cheaper right? They would certainly be useful in very high rx in high index, combined with free-form/double aspheric/premium lenses - where the customer is already spending big.

BTW saw my optician and he is warming to the idea of finalite or hoya 1.6 :)
If he can get me hoya I will definitely try the Nulux EP double aspheric:bbg:

[Darryl Meister]

They would certainly be useful in very high rx in high index, combined with free-form/double aspheric/premium lenses - where the customer is already spending big

I imagine at some point GRIN spectacle lenses will be commercially available. Ophthonix is already using a similar technology for their wavefront lenses. However, I doubt GRIN technology will be used to improve Abbe value or to reduce chromatic aberration. Most likely, it will be used to produce changes in power (progressive lenses, wavefront guided lenses, and so on).

[AWTECH]

Is the only way for a practicing optician to determine if the patient has a problem with the material due to ABBE, by verbal questioning the patient and asking if they see multiple colors when they look to the sides of the lens?

I do not know of any to confirm an ABBE value concern at retail.

Please advise if there is any equipment that can determine the chromatic abberations.

[Darryl Meister]

Is the only way for a practicing optician to determine if the patient has a problem with the material due to ABBE, by verbal questioning the patient and asking if they see multiple colors when they look to the sides of the lens?

Usually, if the wearer's problem is related to the color-fringing produced by lateral chromatic aberration, it will be the first thing they complain about -- and the complaints will include seeing blue or amber along white edges and that sort of thing. Axial chromatic aberration will result in reduced clarity in the periphery, but in my opinion this is less likely to elicit a complaint from the wearer.

[mirage2k2]

Usually, if the wearer's problem is related to the color-fringing produced by lateral chromatic aberration, it will be the first thing they complain about -- and the complaints will include seeing blue or amber along white edges and that sort of thing. Axial chromatic aberration will result in reduced clarity in the periphery, but in my opinion this is less likely to elicit a complaint from the wearer.

Since I have these problems it seems apt that I speak from experience - I see color seperation and blur (out of focus) - the blur is by far the worst thing since you see things go out of focus as you look through the periphery. But I have always put the blur down to the color seperation - perhaps the blur is the result of axial chromatic aberration?

Darryl, wouldn't the color seperation (LCA) also generate a certain amount of blur and general lack of visual accuity, since, in the most extreme case you could be seeing three of everything

[Darryl Meister]

Darryl, wouldn't the color seperation (LCA) also generate a certain amount of blur and general lack of visual accuity, since, in the most extreme case you could be seeing three of everything

Yes, as I noted, axial (LCA) chromatic aberration will result in reduced clarity in the periphery. However, it may be difficult to tell whether the reduced clarity is the result of axial chromatic aberration due to Abbe value, the result of monochromatic aberrations due to poor lens design, or the result of both. In this case, minimizing the monochromatic aberrations by using a good lens design will reduce the overall blur.

[mirage2k2]

I'm looking at your article again -

Lateral Chromatic Aberration (LCA) - this is color seperation generated by induced prism - looking away from the oc = decentration = induced prism - so this is mainly an off-axis problem? Adding prescribed prism would compound this problem?

Axial Chromatic Aberration (ACA) - this is where the different colors have different focal points and this is the lesser evil? - so if and when this is a problem is it a problem in the whole lense, i.e. oc as well as off-axis?

[Darryl Meister]

Yes, sorry, I should have used ACA (axial chromatic aberration is also called longitudinal chromatic aberration, which has the same abbreviation as lateral chromatic aberration). Both axial and lateral chromatic aberration result in "color separation," and you are correct in your assessment. Lateral chromatic aberration will be worse in the periphery because of prism, while axial chromatic aberration will affect the clarity of the lens everywhere -- though the effects of axial chromatic will be compounded by both the color fringing of lateral chromatic aberration and the blurring effects of monochromatic aberrations.

[QDO1]

I suppose wave-front technology is only as good as the algorythm used, and the measurements used for the data

[Cherry Optical]

I've attached two images at the bottom of the post. The first image represents the wavefront analysis of a 5mm beam of light passing through a Varilux Physio lens (with no distance power). The image depicts beams located +8, -4, 0, and 6 degrees to either side of the fitting cross respectfully. A competitor's latest lens design is shown in the second image. Essilor does not typically do "comparison" marketing, and I attach these here only for illustration.

In short, it is unfortunate and unintended if anyone misconstrues what I believe to be a rather carefully thought out explanation of the product- from both a marketing and technical standpoint. To the degree that I was involved in those messages, accept my apology for any shortcomings in scientific/technical content. I'm sure you would have a much more interesting conversation with several ladies and gentlemen from St. Maur, France on the topic of aberration, design, etc.

The fact is, this product was created via a design process which was able to analyze the wavefront passing through each surface and manufacturing processes which are capable of translating a design to the lens which eliminates/reduces/moderates the affects of higher order aberration and unwanted astigmatism. The extensive wearer tests that have been conducted seem to bear out the design's superiority over anything (Essilor or otherwise) currently out there.

I'd much rather hear it from you Pete. BTW: I think I know who's competitive lens you have choosen there. Good call!

The lens seems to be performing well. I have about a dozen pairs in the lab for current Panamic wearing dispensing Opticians, so that will be my test. We currently have done 80+ Physio/Physio 360s so far with little to no problems. My market will determine what I sell.

Adam

[hardbox_happy]

Darryl Meister,

i had read the article that you post on opticampus,have some question is that any progressive design, once the Add increase,that mean the reading portion,or the distortion will be more?

[Darryl Meister]

i had read the article that you post on opticampus,have some question is that any progressive design, once the Add increase,that mean the reading portion,or the distortion will be more?

The distortion always increases as the Add power increases.

[Barry Santini]

Yes, as I noted, axial (LCA) chromatic aberration will result in reduced clarity in the periphery. However, it may be difficult to tell whether the reduced clarity is the result of axial chromatic aberration due to Abbe value, the result of monochromatic aberrations due to poor lens design, or the result of both. In this case, minimizing the monochromatic aberrations by using a good lens design will reduce the overall blur.

Darryl,

correct me if i'm wrong, but peripheral (off-axis) color is correctly called lateral chromatic aberration, not longitudinal, which is on axis... yes?

barry

[Darryl Meister]

A lens technically suffers from both lateral and axial chromatic aberration in the periphery of the lens. Axial (longitudinal) chromatic aberration still results in the blurring of colors in the periphery as each color comes to a focus at a different distance from the image plane, while lateral (transverse) chromatic aberration results in different image sizes for each color -- producing the infamous "color fringing."

[Barry Santini]

I say again that lens technology now widely exceeds to accuracy and precision of traditional refraction.

"this or this" ..."or that"... is soooo last millenium....

I for one, look forward to a new paradigm in refraction...and none too soon.

That said, we're stuck for now with what's been doin'. Who knows the following:

dioptric value of 20 feet

Dioptric value of 10 feet

Average dioptric value for Night myopia for 25 year olds, and for 45 year olds

New ANSI power tolerances for progressives

Mix the above all up on the right day and in the right way, and...

you get patient disatisfaction. All of the above is easy to address..right now!

...without any free form complexity and expense.

What da ya say? For me its let get refraction *removed* from being considered (somehow) a medical procedure, and let us expand it and bring it into line with current lens technology


FWIW

Barry Santini, ABOM

answers: 0.16D; 0.33D; 1.25D & 0.37D; respectively; 0.14D (now *that's* alot of possible additive power error to compromise distance acuity)