Zeiss Individual asks for POW measurements for each patient. Why cannot I specify POW for any digitally surfaced progressive, like Autograph 2 , to compensate for a frame that cannot be properly pantoscoped? Darryl?
Zeiss Individual asks for POW measurements for each patient. Why cannot I specify POW for any digitally surfaced progressive, like Autograph 2 , to compensate for a frame that cannot be properly pantoscoped? Darryl?
It depends if the software is capable, and whether that capabilty is implemented (read "paid for"). Keep in mind that free-form generators are capable creating complex surfaces as well as simple surfaces, that may or may not be optimized. Caveat emptor.
You can for the Auto 2 PAL, but not the SV lens, at least not yet....like Autograph 2 , to compensate for a frame that cannot be properly pantoscoped?
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Robert summed it up nicely. Not all free-form lens suppliers actually optically optimize their progressive lenses based upon the wearer's specific prescription and/or position of wear. This is why it is important to fully understand the features of a given product.Why cannot I specify POW for any digitally surfaced progressive, like Autograph 2 , to compensate for a frame that cannot be properly pantoscoped? Darryl
For CZV products, at least, there really is no ambiguity in defining the pantoscopic angle: It is the vertical angle that the frame plane makes from a plane orthogonal (perpendicular) to the line of sight at the fitting point of the lens. When measuring the pantoscopic angle, since there is no easy way to "visualize" a plane perpendicular to the line of sight without special equipment, it is typically measured from a vertical plane, which means that the line of sight should be relatively level (i.e., looking "straight ahead").But, the jury is still out as to just how this measurement is to obtain reliably obtained, independant of and without co-mingling it with client head posture.
Darryl J. Meister, ABOM
Help me out, here.
I've seen reference on a few threads, here, to the patients head angle as a variable in pantoscopic tilt.
I'm under the converse impression that the REASON for pantoscopic tilt is so the patient's head angle DOESN'T MATTER in it's relationship to the lens.
Which is wrong?
Having participated in some of those discussions, myself, I can certainly understand your confusion. Some of the information presented in one or two of those threads was ambiguous; some of it was completely inaccurate.I've seen reference on a few threads, here, to the patients head angle as a variable in pantoscopic tilt... I'm under the converse impression that the REASON for pantoscopic tilt is so the patient's head angle DOESN'T MATTER in it's relationship to the lens
Unless the frame is placed on the face in a different position, the relationship between the position of the eyeball and the frame + lens plane does not change. Hence, the angle between the lens plane and the line of sight, once the line of sight passes through the fitting point of the lens, does not change with head movement either. This is essentially the angle the lens makes with the line of sight in "primary gaze."
Of course, as the line of sight moves across the lens it forms a different angle with the lens plane. Lens designs properly optimized for the wearer's position of wear have the optics of the lens calculated at each new viewing angle, assuming that the lens is in a fixed position with respect to the position of the eyeball. (Technically, the effective center of rotation of the eyeball may change slightly with certain eye movements, but this effect is generally ignored in lens design.)
However, for any given wearer, the relationship between the frame + lens combination and the position of the eyeball may differ significantly. Even wearers in the same frame style can expect their lenses to rest differently relative to the eyes when worn, depending upon their particular facial anatomy. So the pantoscopic tilt angle of the frame + lens combination is indeed an important variable for optical optimization of the lens design.
That said, head posture can influence how pantoscopic angle is measured. Since the angle of the lens must be measured with respect to the line of sight in primary gaze, which should also intersect the fitting point of the lens when corrected positioned, any unwanted vertical head tip can throw off this measurement. Of course, it will throw off the fitting height measurement as well. Much of the discussion that you are referring to may have occurred in the context of measuring pantoscopic tilt accurately.
Darryl J. Meister, ABOM
Hi Barry.
Regarding our previous discussion, I still think the Pantoscopic angle is not an fixet value, and therefor nearly impossible to measure. It can only be an average value.
As you know, this is my personally point of view, and will for sure get someone up in the red zone :bbg:
Mike
Since eyewear is impossible to fix in place with respect to its fitting and adjustment, I'd have to agree with you. If you meant something else, by all means please go to the *red* zone!
Barry
As I said, some of the information presented in the other threads was completely inaccurate. Rather than rehash the entire discussion appearing in those threads, however, I will simply defer to another thread ostensibly dedicated to the subject of confusing eyecare professionals on the subject of free-form technology: http://www.optiboard.com/forums/show...w-this-secrets.Regarding our previous discussion, I still think the Pantoscopic angle is not an fixet value, and therefor nearly impossible to measure. It can only be an average value.
Some technical concepts seem to be misapplied or at least applied ambiguously in your post above, even as these concepts have been implemented with your own product (Shamir Autograph):
1. If a measurement value varies upon taking repeated measurements of the same person, it is reasonable to take an average of those individual measurements. You can certainly do this right now for any free-form lens with customization for the position of wear, including Zeiss Individual. For that matter, you could do this for any measurement for any lens, including the fitting height of traditional progressive lenses.
2. If only a single measurement value can be utilized for every person, it is reasonable to use a representative value based upon the average of the entire population of potential wearers. For instance, if you order GT2 3D lenses by Zeiss, or do not supply specific position of wear measurements with Zeiss Individual, such "representative" or "default" values are used, instead. This is actually the concept that you are referring to, which has nothing to do with the first concept.
I don't necessarily agree that it is "impossible" to keep eyewear relatively stable through proper adjustment, at least within a reason, but we were actually discussing the apparent shift of eyewear with head movement in the earlier post. For instance, if you measure the pantoscopic tilt of the frame from a vertical plane, this angle will change as the wearer tips his or chin. However, the lens, itself, generally does not change with respect to the eyeball.Since eyewear is impossible to fix in place with respect to its fitting and adjustment,
Darryl J. Meister, ABOM
Darryl, nice to see you have finally learned that the Panto is only an average measure. Just as I have said many times.
Now you only need to learn a little about Vertex as well. As I have already claimed, it is impossible to measure Vertex prober as well, and does not influence the optical design noticeable.
SO all in all Panto and Vertex is somehow marketing gimmicks.
I do not say Individual and GT2 is same same if you use default measures, because I agree that Individual is a much better lens than GT2, just as Auto II is a better lens than Auto Plus. BUT that is not because of the Panto & Vertex, thats because of two complete different designs.!
But one thing your right about. We dont need to discuss that in this thread.
Mike
I'm afraid we'll just have to agree to disagree, Mike. I believe that I explained these principles to you very clearly in the other thread, ad nauseam, so I don't really have anything more to add regarding your opinion about your Shamir Autograph product.Darryl, nice to see you have finally learned that the Panto is only an average measure. Just as I have said many times.. SO all in all Panto and Vertex is somehow marketing gimmicks... We dont need to discuss that in this thread.
You obviously believe that position of wear measurements are pointless (well, all of them with the exception of wrap angle, since you currently use that one for some reason), and have chosen not to offer your customers this particular Prescriptor option with the Shamir Autograph lenses you supply.
Darryl J. Meister, ABOM
Your right. I think Vertex and Panto are pointless, unless you could measure the average value prober enough, but you canīt, I canīt and no one canīt. Only laser equipment mounted on the head in a week could give you a usable average. And for what reason? NONE because the pow-, and design comp. would be minimal anyway.
Mike
While I find the notion of becoming a "cyborg" intriguing, I would recommend instead using one of the digital centration systems specifically designed for capturing these measurements, such as the i.Terminal, or using one of the inexpensive manual fitting tools that are also available.Only laser equipment mounted on the head in a week...
;)
Mike, as you know, I routinely disagree with most of what you post on this subject, since it is more often than not wild conjecture with no technical substantiation or clinical validation that serves only to support your own product positioning. But, in this particular instance, I think that you are still simply commingling the two very distinct concepts that I described above.unless you could measure the average value prober enough
Darryl J. Meister, ABOM
Hi Darryl.
First of all Iīm not market our own product with these personally claims, because we need the measurement to Auto II just as anyone other "individual" product.
I fully understand your point #2, but cant see what you think I donīt understand with this. I told you that Individual IS actually more individual comparing to GT2 especially because of the panoramic angle.
But you know, because I know, that GT2 design is not even close to the Individual design. Itīs a complete different design comparing with Individual. AND thats the MAIN reason for the better Individual design. Not the panoramic, not the Vertex but the improved design. As manfacturer of lenses, we will always use our best design for the most expensive, right? With Freeform technology we can change the design as we like to, and put in into different price levels as we change the size of the vision area, and the sharpness. This is not magic as you like us to think.
Mike
Case in point, my points dealt strictly with the notion of "average pantoscopic tilt," irrespective of any particular product, yet you are now off on an unrelated tangent comparing the performance of GT2 and Individual.I fully understand your point #2, but cant see what you think I donīt understand with this. I told you that Individual IS actually more individual comparing to GT2 especially because of the panoramic angle
I'm not really sure whether you are referring to GT2, which is a semi-finished lens, or to GT2 3D, which is a free-form lens. In any case, both are based upon the lens design platform used to design Individual, although there are subtle optical differences between the three lens designs (e.g., GT2 has more near zone emphasis, GT2 3D is a softer design overall to improve binocularity).But you know, because I know, that GT2 design is not even close to the Individual design. Itīs a complete different design comparing with Individual. AND thats the MAIN reason for the better Individual design.
Remember that I was the one supporting my arguments with scientific reasoning and actual optical comparisons. You were, and still are, the one supporting your arguments with little more than your personal assurances. I don't believe in magic, which is why I routinely encourage eyecare professionals to look beyond the "smoke and mirrors" of poorly supported marketing puffery to understand, instead, the actual implementation details of the lens design.This is not magic as you like us to think
Darryl J. Meister, ABOM
Hmmm I thought it was night or VERY early morning in Kansas? Are you sitting in Europe?
About "Scientific reasons" thats okay, but Science alone is not the answer of right and wrong. Itīs only a tool.
You can make all the science about cars, but you still have the slowest car.
Mike
It's very late, but I'm currently discussing a project with my German colleagues in Aalen.Hmmm I thought it was night or VERY early morning in Kansas?
I don't disagree with you. Clinical validation is very important. And you will see some very impressive clinical validation for Zeiss Individual very soon.About "Scientific reasons" thats okay, but Science alone is not the answer of right and wrong. Itīs only a tool.
Darryl J. Meister, ABOM
Good grief, here we go again! Still, I can't help but interject:
Obviously, Mike wears those cool, continuously-panto-adjusting glasses, probably with mirrored lenses, that way, people of different heights can't see his eyes and it always appears as though he is looking in their direction!
C'mon Barry, surely you would agree that if you have properly fit someone's eyewear, it will remain in pretty much the same location on their face from one second to the next??
Mike, maybe you need a new refraction, as that is not what Darryl said at all. He explained it very well here, not that I would expect you to agree or understand:
"Having participated in some of those discussions, myself, I can certainly understand your confusion. Some of the information presented in one or two of those threads was ambiguous; some of it was completely inaccurate.
Unless the frame is placed on the face in a different position, the relationship between the position of the eyeball and the frame + lens plane does not change. Hence, the angle between the lens plane and the line of sight, once the line of sight passes through the fitting point of the lens, does not change with head movement either. This is essentially the angle the lens makes with the line of sight in "primary gaze."
Of course, as the line of sight moves across the lens it forms a different angle with the lens plane. Lens designs properly optimized for the wearer's position of wear have the optics of the lens calculated at each new viewing angle, assuming that the lens is in a fixed position with respect to the position of the eyeball. (Technically, the effective center of rotation of the eyeball may change slightly with certain eye movements, but this effect is generally ignored in lens design.)
However, for any given wearer, the relationship between the frame + lens combination and the position of the eyeball may differ significantly. Even wearers in the same frame style can expect their lenses to rest differently relative to the eyes when worn, depending upon their particular facial anatomy. So the pantoscopic tilt angle of the frame + lens combination is indeed an important variable for optical optimization of the lens design.
That said, head posture can influence how pantoscopic angle is measured. Since the angle of the lens must be measured with respect to the line of sight in primary gaze, which should also intersect the fitting point of the lens when corrected positioned, any unwanted vertical head tip can throw off this measurement. Of course, it will throw off the fitting height measurement as well. Much of the discussion that you are referring to may have occurred in the context of measuring pantoscopic tilt accurately."
I really doubt you have the credentials to say what Darryl needs to learn; might want to take a little of your own advice there.
Ridiculous. Are you serious? I sure hope not. Probably so though.
Now don't get me wrong here people, I'm not pretending to be the smartest optician on the planet, but seriously, this Mike guy has his own agenda. Not only does he try to make us all think that his product is the only one worth having, but he also likes to belittle people and talk down to them when they say there may be other options or answers. It's pretty obvious that Darryl knows his stuff; the jury's still out on Mike. We all know that vertex and panto can and do make a difference in vision. Well, all of us except Mike, that is.
Bryan Finley, Florida Board Certified Licensed Dispensing Optician
From my point Of view
I agree that The panto and the vertex can never be exact 100% but is better to have one near value then nothing that is why i think that the vertex and the panto can not be marketing issue to sell more!!
also the calculation software that are in the market and that calculate the PAL surface prouve that the panto and the vertex can change a lot the power espacelly for a panto more then 10°
regards
Hamza Mahmoud
Mail : mahmoud.hamza@optylab.com
Web : www.optylab.com
Okay finney.
Obvious you are wery low educated here among others. Without sounding lecturing, I will ones again explain for you, and king Salamon, why Panto is a gimmick measure and Panoramic is not.
We all know that by increasing the Panto angle a little more we can sometimes solve a reading issue, but this is only because some frames are adjusted more vertical on the nose than others. It can happens even though you have customized a pair of Zeiss Individual, Impression, Auto II and even though you have measured the Pantoscopic tilt prober. If the Pantoscopic tilt are 0-5 degrees some gets reading problems you can solve by increasing the angle!
I and other well educated and informed opticians, know that most people, cant feel any different at all when changing the Pantoscopic tilt between 5 and 15 degrees.!
You and others obvious dont know why. I tell you. Because the tilt from 5-15 degrees donīt make any noticeable changing in the design, and the small changings only affect a very small area of the lens, and thats the small reading area.
Otherwise the Panoramic angle. THATīs a different story. When you change the panoramic angle just 5 degrees it immediately change the comfort of the lens. You get horrisontal prism effect both in the distance and in the reading zone, and destroy the size of the reading area every time you increase the pantoscopic angle with just 3 degrees. Darryl, you and others should be careful with claiming that Iīm wrong when you donīt know a s*** about this. Someone here are very low educated in optics or just students that believe in all Mr. Meister tell you. Are there any well educated opticians left in this forum at all?????
You are bullying the wrong person here finney and please tell me what you think my agenda is? I donīt see your point.
Last edited by OCP; 03-12-2010 at 07:20 AM.
First of all, I want to reiterate that both measurements are important. While I still find it odd, and more than a little self-serving for your product, that you believe one position of wear angle is "very important" while the other is a "gimmick," I am willing to entertain your reasoning one last time.Panto is a gimmick measure and Panoramic is not... Because the tilt from 5-15 degrees donīt make any noticeable changing in the design, and the small changings only affect a very small area of the lens, and thats the small reading area.
Secondly, there is no optical difference between pantoscopic and face-form (panoramic) tilt. Each introduces the exact same optical effect, oblique astigmatism, albeit with a different cylinder axis. And each interacts with the optics of the lens design in similar ways. I already posted contour plots for you to look at showing the effects of this tilt, which you essentially ignored since they disproved all of your wild conjecture, in the other thread that you're attempting to rehash here.
What you're describing is not an optical phenomenon. You're simply increasing the field of view through the near zone by bringing it closer to the eye. Or reducing the field of view through one axis or the other by tilting the lens about an axis perpendicular to it. And either pantoscopic tilt (vertical compression) or face-form tilt (horizontal compression) will reduce the field of view.If the Pantoscopic tilt are 0-5 degrees some gets reading problems you can solve by increasing the angle! You get horrisontal prism effect both in the distance and in the reading zone... When you change the panoramic angle just 5 degrees it immediately change the comfort of the lens.
Further, this kind of non-optical reduction in field of view due to lens tilt is actually quite negligible for 5 deg of face-form tilt. But, since I like to stick to facts and not conjecture, I will "do the math" for you since you continue to refuse to do it yourself, assuming a near zone size of 20 mm made on a 6.00 Base hard resin (1.500) puck with a 5 mm center thickness:
Apparent Width = Actual Width * COS Tilt
Apparent Width = 20.0 * COS 5
Apparent Width = 19.92 mm
And, for the induced prism that you mentioned:
Induced Prism = Center / Index * Base * 100 * TAN Tilt
Induced Prism = 0.005 / 1.5 * 6.00 * 100 * TAN 5
Induced Prism = 0.17 Prism Diopters
So, ignoring the optical effects of oblique astigmatism for now, which you have no interest in for some reason, you are looking at a reduction in near viewing zone with of less than 0.1 mm and induced horizontal prism of 0.17 PD with 5 deg of face-form tilt. And these two effects are solely responsible for the major "discomfort" for wearers that you describe above as well as for the general dissatisfaction that wearers may express for a given pair of progressive lenses?
Then I guess it's a good thing that we optimize the Individual lens design for face-form tilt, in addition to eveything else.
After fifteen years, that's probably the single silliest thing that I have ever read on OptiBoard. And I say that with the lens designer's version of CZV's free-form optical design engine literally running on my computer in the background.Darryl, you and others should be careful with claiming that Iīm wrong when you donīt know a s*** about this.
Mike, you made your agenda very clear in your other threads. Further, I'm not bullying you. Nor do I engage in childish insults and ad hominem. In fact, I would prefer not to get into these protracted debates with you, since you typically resort to insults in the absence of any scientific reasoning or clinical evidence to support your arguments.You are bullying the wrong person here finney and please tell me what you think my agenda is?
In any event, as the title indicates, this thread about position of wear customization in Zeiss Individual and similar products. Since you are obviously not sufficiently familiar with the technical details of the position of wear customization of Zeiss Individual, your posts in this thread serve only to attempt to derail legitimate discussion of a competitor's product with wild speculation. You have already started similar threads on this topic, like this thread, ostensibly for the sake of promoting your own product, and I'm sure that your input in those threads would be much more appropriate.
Darryl J. Meister, ABOM
You still mix up design and power compensating.
I did never say Panto is irrelevant.
I did never say panto does not influence the power comp.
-but I did say some here are very low educated in optics.
This is ridicules as long you think Zeiss individual and Zeiss Infral is the answer of all the needs and all optical issues. Your so wrong.
Do you remember me attempting to explain to you in great detail the differences between compensating for lens power and optimizing the lens design for the position of wear in your other thread? In particular: Here and Here.You still mix up design and power compensating.
You've actually been contradicting yourself on this topic to suit your needs. In this thread, alone, you've stated:I did never say Panto is irrelevant.
"Pantoscopic tilt DOES matter. The issue is to measure this value prober, "
"I will ones again explain for you, and king Salamon, why Panto is a gimmick"
"most people, cant feel any different at all when changing the Pantoscopic tilt"
"I think Vertex and Panto are pointless"
You originally argued that pantoscopic tilt is important, but because it is constantly "changing on the face" somehow, impossible to measure. Once other participants expressed disagreement with this notion, however, you simply started arguing that pantoscopic tilt is instead "pointless" because it has no optical effect on the wearer.
I don't think that Zeiss Individual is the answer to all optical issues. Nor do I think that Shamir Autograph is.This is ridicules as long you think Zeiss individual and Zeiss Infral is the answer of all the needs and all optical issues
Yes, you've made your opinion clear. Unfortunately, you continue to do a poor job of supporting that opinion.Your so wrong
Last edited by Darryl Meister; 03-13-2010 at 02:40 AM.
Darryl J. Meister, ABOM
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