Thanks, Darryl. I've added my emphasis.
The thing is, though, that I'm thinking that NONE of the manufacturers are willing to divulge just what their "secret (design) sauce" actually is, so an ECP could begin to differentiate potential design benefits.
My take: all the high quality designs are closer than they are different.
Discussion?
B
I agree that most manufacturers are very vague regarding the actual lens design attributres of their free-form products, but I'm not sure how much more detail anyone could possibly want from Carl Zeiss Vision regarding our "secret (design) sauce": Individual white paper and Individual Single Vision white paper...The thing is, though, that I'm thinking that NONE of the manufacturers are willing to divulge just what their "secret (design) sauce" actually is, so an ECP could begin to differentiate potential design benefits
Darryl J. Meister, ABOM
I apreciate the graph on page 3 "Wavefront Aberrations" I like the visual of astigmatism, defocus, trfoil, and coma. It would be noticed that by the image you could say that coma is reduced by more than 50%, but you can see that this effect is negligable same with trfoil. It's not the information available, but it's raw form that allows the optician to educate themselves.
Another great example that I have liked about this white paper: traditional lens right next to the individual on the base curve chart, it becoems evident that in certain cases the traditional lens is going to offer comparable optics to the individual, this chart can actually be used to see the "WOW" effect that could be expected from the individual version.
Data was calculated using a 6mm pupil diameter, this is important when comparing too small of a pupil size and effects from coma, sph aberration, etc are minimized making the lens performance better than expected in a real life scenario.
Design is produced on the fly with the prescription taken into account, this is very important as I mentioned above in my questions regarding what I need to know about a PAL design, if the lens is compensated for prescription this is done so that the DRP is optimized, however if the compensation is done to the design as well we are ensured that the entire surface matches the optimal perfromance that the designers intended.
"Each Zeiss Individual
lens is optically optimized online by Carl Zeiss Vision’s opticaldesign engine using the wearer’s exact prescription requirements"
Does this mean that the software resides on the Zeiss servers with the lab LMS connecting and sending the needed data to Zeiss and then recieving the required data file to produce the lens? Almost seems that way with the wording.
"By fine-tuning the optical design of the lens for the
exact prescription, residual lens aberrations are virtually eliminated,
resulting in up to 50% wider fields of clear vision."
I make my assumption that this means compared to the minkwitz theory. Is that something that you can confirm or deny?
"Furthermore, unwanted changes to the location and shape of the
viewing zones are also eliminated, preserving the binocular utilityof the lenses with wide, symmetrical fields of view"
The lens has horizontal symmetry.
"Moreover, progressive lenses produced by free-form surfacing must
be frequently validated against the target designs by “mapping”quality guidelines and optical design specifications."
the optics over the entire lens (Figure 17). Failure to validate the
production quality of a free-form surfacing process on a regular
basis can lead to inferior quality compared to traditional lens
molding, if the process begins to “drift” from best practice. Freeform
progressive lenses from Carl Zeiss Vision must meet stringent
Thank you for the open discussion on the QC measures needed to deliver the "promise". This white paper is truly exceptional and I have a copy sitting at both home and work.
Yes, that's exactly what it means: The laboratory's computer connects to a central ZEISS server, which calculates the lens design and transmits the data back to the lab.Does this mean that the software resides on the Zeiss servers with the lab LMS connecting and sending the needed data to Zeiss and then recieving the required data file to produce the lens?
In this particular context, the 50% wider claim pertains to the increase in fields of view produced by optimizing the lens design for the wearer's exact prescription requirements and position of wear.I make my assumption that this means compared to the minkwitz theory. Is that something that you can confirm or deny?
However, because Individual also utilizes a variable corridor length, the viewing zones will also be wider due to Minkwitz's theorem at many fitting heights compared to "standard" progressive lenses with only one or two corridor lengths.
I certainly appreciate the positive feedback. I also do all of the optical analysis, layout work, and illustrations for our technical pieces, so these take a fair bit of effort to put together. So I'm glad to know that someone out there is reading this stuff!This white paper is truly exceptional
Darryl J. Meister, ABOM
-Tony
I got mine from my rep last Friday. Pretty neat how they did the dihedral (face-form angle) measurement. I was using Darryl's "Basic Frame Wrap Angle Protractor" but this looks like it will be more accurate, although the two I checked so far were withing one degree. The Panto measurer seems a little stiff- I'm concerned I might scratch the lens on the finished product at dispense. I'll probably keep using Zeiss's non-contact metal device with the similar plumb line system. The vertex measuring ruler is better than guessing, but for more accuracy I would use a distometer.
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.
I like the basic idea of the tool. I chuckled at first glance. My first impression is how can you claim to have such highly sophisticated and accurate lenses, made with highly sophisticated machinery, by using measurements from something so rickety and unsophisticated?
:o:cheers::cheers::cheers:
This is actually one of the basis ideas from Shamir, not to have sophisticated machinery to make the best lenses out there.
-and the lenses will be ordered with perfect frame curve measure every time.
Look at the little Pat.#. This is the only tool that measure the frame curve where it´s most important....right in the pupil. :)
Mike
Last edited by OCP; 12-23-2009 at 03:38 AM.
I have not yet seen this Shamir tool, but measuring and/or calculating the frame, (lens curve), is very important. As the frame angle and lens angle are different.
To illustrate think of an 8 base wrap large A measurement frame. With a narrow PD. The angle of the front of the lens compared to angle of the frame is much less. With a 0.50 base curve lens in the same frame the frame angle is now almost the same as the lens angle.
I think there is more room for error by the optician trying to accurately measure the lens curve vs. measuring the frame curve angle.
Hi Fezzy, glad to know all's ashore. : )
Correct, Mike,Please note that Shamir are using a different calculation value compared to other devices. The value is 90 degree higher.
Mike
My understanding is:
If the ECP supplies a wrap angle (5, 10, degrees), the visual software program (Prescriptor) will know that the frame was likely placed on a printed angle chart, the PD was not involved, and adapt the calculations.
If the ECP supplies a wrap angle (95, 100, 105 degrees), the software will know that the Panorameter was used, and know that the PD is incorporated, and adapt the calculations.
And, Robert, I agree, dusting off the ol' distometer is a good thing....a trusted and trued (no pun intended) device.
: )
Laurie
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.
I think a lot of people are brain washed. Most progressives are basically designed the same with about 50-60% distortion (just in different areas) As for the whole free-form digital hype the detection level is so minor. I have yet to receive a WOW response. It will be the norm in the future which is great but until the cost comes down considerably I cant justify passing the cost on to my customers. which are well informed, consulted and never sold.
klsoptical.com
Last edited by unbi'ased; 04-02-2010 at 04:52 PM.
Maybe you have not seen it yet but the combination of cosmetic results and optical results that are now possible get WOW reports from many other opticians. The design and capabilities of the manufacturing does matter. There are some good designs that are not any more expensive than a premium molded lens.
Just thought I'd share. I'm at work so did not have time to look over all 8 pages of posts but I found this site very informative and detailed as to technical characteristics of FreeForm/Digital lens and all progressives. It looks to be kept up and very current. Some of you may be already aware of the site but wanted to share it in this thread post.
http://www.thelensguru.com/index.php
may i know where to find more information for FreeForm technology?actually i dont quite understand about this design?
You might have a look at Optics of Free-Form Lenses.
Best regards,
Darryl
Darryl J. Meister, ABOM
When patients ask what the difference is when comparing the same level of technology across brands, I find
I really dont have an answer except to say they are comparably similar - some people prefer certain brands. I try and explain
that the "best" (read:more expensive) doesnt neccessarily translate into a noticeble difference in vision. Except in cases where the Rx is more complicated (high sph/cyl/add); I would prefer to see them in better technology. I unfortunately dont have the Rx to do comparisons myself yet, so I rely on listening to people who have no vested interest : dispensers who have experimented themselves or customers feedback on previous lens choices.
Lastly where is this elusive Pro's Only forum?
Now with "Acti- Lift" technology!
http://www.tide.com/en-US/product/tide-original.jspx
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