http://www.integratedlens.com/stage/...ligraphy.shtml
Did anyone ever fitting this free form PALs ? I would like to hear the comment. :D
http://www.integratedlens.com/stage/...ligraphy.shtml
Did anyone ever fitting this free form PALs ? I would like to hear the comment. :D
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Nope!
Might it be that all rear surface free form proressives boast the same advantages?
mike.elmes said:Technically it is possible for all backside freeform lenses to have the same advanages but very doubtful. The math involved in calculating these designs can be quite different.Might it be that all rear surface free form proressives boast the same advantages?
To someone not familiar with an automobile they can be described as vehicles with 4 wheels. This does not mean a Chevrolet and a Ferrari have the same advantages. If you are looking for the fastest the answer is different than if you are looking for the most economical.
There are significant differences in freeform PAL designs eventhough the concepts seem very similar. Overall I would say a freeform designed backsurfaced PAL will be a better design than a traditionally surfaced PAL but there can still be many advantages of one excellent design over another.
with corridor 13 , 15 and lastest news they have corridor 11 nowwwww
Last edited by suwit; 12-12-2006 at 09:31 AM.
:drop: :drop: :drop: :drop: :drop:
So is this the design that is now marketed under the ProFit Calligraphy design?
John
Any body notice that they sell these things compareing them to conventional spherical lenses and graphs? Seem to be using the same graphs and comparisons to sell aspheric lenses when they came out vs spheres.
Chip
I'm about to try the Caligraphy. Any more hints, tips, or comments from others who have tried it?
All true free form progressive lenses have the same advantages provided the designs were highly optimized. A back surface compared to a front surface free form will not yield a better design if both designs were optimized equally. A back surface free form with a spheric front will have more disadvantages in the polishing phase than a front aspheric with back progressive or a front progressive with a back aspheric. The disadvantage is the loss of data points in the polishing process.
Doc in China makes a good point regarding quality of orginal design. The same design produced by two different labs can produce products that are different. Polishing is just one area that can cause these differences. Traditional lab processes also have similar risk factors for the ECP.
The production of complex designs requires a multitude of checks and balances. Having the most expensive equipment using a famous design does not mean the end product will be good. Understanding the lens design, the fabrication of the lens design and the result of the finished product requires a deeper understanding to produce a quality, state-of-the-art lens.
My local lab has seen a great deal of variation in the quality of the SAME free form design from different labs that he gets them from. Its to the point that he has dropped certain labs that supposedly were making the same lens.
John
Interesting when you think about it: Your lab offers a freeform design but gets it from a number of other labs that actually produce the lens. The lens design is provided by a lens company. Now you sell this to the patient or customer.
How much value is being offered by each of the firms in this method of lens delivery???
Starting from the ECP there is the order for the lens and there are both the lens design and lens production to deal with. Any other steps are just additional sales and distribution functions.
No doubt about it, you add cost by ordering from your local lab who then farms out design and production to another lab. On the flip side, my local lab is a stickler for quality and scrutinizes the lenses closely before edging and releasing to me, so that has value IMHO, especially with designs where the Rx is run through an algorithm and the powers manipulated during the design phase.
John
Each step can have value and if the charge is appropriate, no problem. With complex designs most local labs have no way to check the accuracy other than traditional lensometer reading of a local power point location.
Most errors are not going to be the result of the lens power surface calculations but rather the processing steps involved. Like most computer data= good data in = good data out, and bad data in = bad data out.
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