Check this out....Definity lens.....

[hcjilson]

Check this out....Definity lens is the subject of our latest Product Review. PAKev has done an outstanding job and will be available to answer any questions.

Please follow this link:
http://www.optiboard.com/forums/show...&threadid=9341

[Ryan]

Great Review!! We recently started selling the Definity and have had wonderful results! ;)

[Bev Heishman]

We also have had wonderful results with the Definity lens in our office. I know of many individuals that have started to make this lens the lens of choice. I am wearing one and really like the distance vision at night time.:)

[Darryl Meister]

There are other "non-customized" products which also use a direct surfacing process. For example, in the 1.67 version SOLAOne is created via a direct surfacing process.

Actually, SOLAOne in 1.67 is customized. Each prescription lens is completely optically optimized for the typical as-worn position. Using proprietary optimization software, a base design is ray-traced for each wearer's prescription and adjusted in order to maximize performance. This process is repeated (iterated) until the best possible design is achieved. You can think of it as an atoric-like correction, specific to each individual prescription, incorporated into the design, but it's obviously more complicated than that. The distance and near powers are also adjusted for the typical as-worn position, so the lab will receive a compensated Rx form.

Best regards,
Darryl

[drk]

I know I'm missing something, so please help me on this.

Does "customization", as Pete describes it, refer to a design that has been compensated for position of wear, as well as Rx?

If so, wouldn't it just be easier for a dispenser to adjust the frames' "position of wear" to a "standard position" that a lens was optimized for, therfore avoiding the need for all this vertex and panto measuring?

Can't lens designers just assume a 12 mm vertex distance and 6 degrees of panto? That's how everyone adjusts frames, anyway (at least until the patient leaves the optical).

Is that what you are saying Sola does, Darryl?

[PAkev]

As indicated in my review, I am aware of other manufacturers in the "free form technology" arena. Although, PAL lens superiority can be argued by folks in the trade all day long, the other half is developing and maintaining a successful marketplace for a good product. Those circumstances were the prevailing reason of using the J&J DEFINITY throughout the review.

Remove yourself from the optical industry for a moment to realize how folks fealt about going for an airplane ride in 1903 with Langley or the Wright Bros. It took a lot of "confidence building" before passengers started standing in line at what we now call airports.

This is where I belive the context of my review supports J&J has done an excellent job of developing a good product while also developing good "End User" consumer acceptance.

Kevin

[Pete Hanlin]

Actually, SOLAOne in 1.67 is customized. Each prescription lens is completely optically optimized for the typical as-worn position. Using proprietary optimization software, a base design is ray-traced for each wearer's prescription and adjusted in order to maximize performance.
The literature indicated "freeform" was used for the 1.67 version only. I made some inquiries at the SOLA booth at VEE, and was told the 1.67 design was the same as the other materials. If I understand your description, the basic design remains the same, but parameters such as the base curve, etc. is customized to provide the best optics for the actual prescription. Thanks for the clarification.

Does "customization", as Pete describes it, refer to a design that has been compensated for position of wear, as well as Rx?
Currently, "customization" falls into three or four general categories- Rx, Lifestyle, Frame Fit, Visual Habits (or some combination of the four).

Most of the customized PALs out there include customization based on the Rx of the wearer. Since the surfaces are created via direct surfacing, the base curve can be optimized for the individual Rx. This customization takes into account the ametropia of the wearer (e.g., myopes receive shorter progressions than hyperopes, higher ADDs receive more inset, prescribed cylinder is optimized, etc.). I believe Shamir Autograph falls into this category, and from the description above, it would appear SOLAOne also does in the 1.67 version of the product.

Generally speaking, variation by Rx is something that exists in several modern traditional PALs as well- to a lesser degree.

Some customized PALs take into account the patient's activities. The Seiko Super Proceed I design has six different progression types which vary depending upon the activities of the patient's lifestyle. In addition, the progression length and inset also vary on the Super Proceed I depending upon the prescription.

Lenses customized to frame fit would include the Zeiss Gradal Individual and Rodenstock Impression ILT. The Zeiss product takes into account pantoscopic tilt, vertex distance, etc., and the Rodenstock product also takes into account the face form of the frame.

There is also customization based upon the wearer's visual habits. This is the approach taken by the Varilux Ipseo product (if there are other PALs in this category, I am unaware of them). The individual's head and eye movements are measured, and the results are used to customize the sphere slope of the design.

Although, PAL lens superiority can be argued by folks in the trade all day long, the other half is developing and maintaining a successful marketplace for a good product. Those circumstances were the prevailing reason of using the J&J DEFINITY throughout the review. Remove yourself from the optical industry for a moment to realize how folks fealt about going for an airplane ride in 1903 with Langley or the Wright Bros. It took a lot of "confidence building" before passengers started standing in line at what we now call airports.
I understand what you are saying, Kevin. One of the things Essilor touts about Varilux advertising is that it increases awareness of product and thus grows the overall market- Varilux and otherwise. Logically speaking, J&J advertising touting new technology should also build the market of those seeking an advanced solution to presbyopia. For the eye care practitioner, it is a good thing to have a patient coming into the office already convinced s/he wants advanced technology.

While the new technology is advanced- and very intriguing- I think it is important to understand what the technology does- and doesn't- actually do. With "freeform," the technology does NOT improve the design. It provides the potential for a more customized design, but it does not in and of itself change the quality of the design. Use "freeform" to create an Essilor Adaptar and you don't have an improved Essilor Adaptar- you just have the same design created with a different process.

Freeform should be exciting, because it does give us the potential to have customized designs. On a grander scale, however, it also gives manufacturers the opportunity to launch MORE designs. After all, the big impediment to launching new designs is mold and inventory production- "freeform" requires neither and therefore creates an easier delivery method for new designs.

Also important to consider, however, is that "freeform" or direct surfacing technology is still developing/evolving. It is a tougher process to control, and verifying the results can be challenging (what equipment does the typical lab have to validate the conformance of a PAL surface to the original design?).

[Darryl Meister]

The literature indicated "freeform" was used for the 1.67 version only.

And the literature is correct. ;) Your statement specifically referenced the 1.67 product, which is why I clarified that bit.

I made some inquiries at the SOLA booth at VEE, and was told the 1.67 design was the same as the other materials.

The basic design is the same, before any additional optimization is applied. Perhaps this is the source of the miscommunication.

but parameters such as the base curve, etc. is customized to provide the best optics for the actual prescription.

It's actually more involved than that. The basic SOLAOne design is the starting point (or base design). The prescription and fitting parameters are then fed into the software. The entire lens is then essentially redesigned by optimizing the base design with the exact prescription and typical position-of-wear parameters, using ray tracing and merit functions and such. Consequently, all of the viewing zones, which would normally become restricted as the prescription moves away from the "optimal Rx" of a semi-finished lens blank, are kept nice and big, and the levels of blur are kept consistent with the original base design.

The result would be somewhat similar to the complex atoric designs produced for Rodenstock Multigressiv and Zeiss Gradal Top OSD... Though, since the atoricity is combined with the progressive surface, and done so in a more generalized fashion, we don't call the lens "atoric." Additionally, we even allow the optimization to change the prescription as much as needed at the distance and near measurement points to ensure that the wearer experiences the most accurate prescription possible. Consequently, the entire lens performs as well as possible, without the restrictions inherent in a semi-finished lens.

Is that what you are saying Sola does, Darryl?

Exactly. At present, for the "as-worn" fitting parameters used in the optimization I described above, we use numbers derived from a large sample population of wearers. Most jobs won't vary far from these measurements, and the differences in the optimization would be relatively small for most prescriptions anyay. But, more importantly, most dispensers don't have the tools to measure these fitting parameters accurately at this point.

As indicated in my review, I am aware of other manufacturers in the "free form technology" arena. Although, PAL lens superiority can be argued by folks in the trade all day long, the other half is developing and maintaining a successful marketplace for a good product.

I think Pete's point is quite valid. Ultimately, the end user (that is, the wearer) does not care how the lens was made, but rather how it works. There is no inherent advantage to free-form or direct surfacing technologies for the wearer, unless the manufacturer has taken the opportunity to apply some sort of individualized customization/optimization. Otherwise, it's just another manufacturing method. Basically, we need to remember that free-form technology isn't a benefit for the wearer, but it can be used as a vehicle to deliver features that are beneficial to the wearer.

Best regards,
Darryl

[Jim Stone]

Look out verilux, they are comming after you!. I just saw a new tv ad, that said, if you wear bifocals or progressives,things have a way of sneeking up on you. You need difinity. :D

[Pete Hanlin]

Consequently, the entire lens performs as well as possible, without the restrictions inherent in a semi-finished lens.
In other words, the freeform process allows a lens designer to go back to the Punktal concept Zeiss introduced in the early 1900s (every Rx had its own particular curvature to reduce marginal astigmatism). Tillyer grouped the powers into about a dozen base curves, and today products generally have 5 or 6 (aspheric products usually having more).

It's actually more involved than that.
Well, I did say "base curves, etc." ;)

The biggest advantage to freeform technology- in my opinion- is the inventory reduction that will result. Reducing the inventory levels of your local lab isn't all that sexy of a message, however, so most of what we will continue to hear (and in some of our cases, say) from manufacturers is how "optimized" the designs can potentially become.

Standing in the path of all this wonderful innovation is going to be practicality of it all. After all, it took about three decades for the industry to go from toric to corrected curve lenses- even though the price points were about equal. My suspicion is the cost of direct surfaced lenses will remain substantially higher than molded/traditionally surfaced product for some time. Mainly because it is difficult to produce lenses en masse using direct surfacing (and as more production is required, the typical yield problems associated with ramping up a new technology will probably kick in as well). The question will then become- do the "optimized" lenses provide performance which is superior enough to the "traditional" lenses to justify the extra expense (and delivery time)? For most prescriptions, the answer is probably going to be "no."

In my view, apart from the inventory savings direct surfacing may eventually provide, the optical design portion of the technology is kinda like the Ford GT (unveiled this year). At $180,000, it is truly a marvelous machine- however, Ford isn't planning to sell millions of them. Its a "see what we can do" product. Essilor, Rodenstock, Zeiss, Seiko, SOLA, Shamir will each roll out their versions of direct surfaced product- and (like traditional lenses) all of them will have design features to tout. Wearer acceptance will be in the high 90s% for pretty much all of them, and we'll continue to have fodder for our debates for generations to come.

[For-Life]

So Pete, with free form technology offering a better way of inventory management does that mean that when free form technology becomes more popular that progressive lens costs will go down. I know Walmart and Dell work with Just In Time management where they carry only the inventory they need (Dell carries no inventory except for that being processed) and order only when they need the inventory. By doing this they keep their costs down. So with free form being a more efficient way to manage lens inventory does that mean that companies will be charging less?

[Jim Stone]

For-Life said:
So Pete, with free form technology offering a better way of inventory management does that mean that when free form technology becomes more popular that progressive lens costs will go down. I know Walmart and Dell work with Just In Time management where they carry only the inventory they need (Dell carries no inventory except for that being processed) and order only when they need the inventory. By doing this they keep their costs down. So with free form being a more efficient way to manage lens inventory does that mean that companies will be charging less?

Right now there are royalties involved in programing that keep the prices up. Maybe when more "points files" become available the cost will be more competitive. Some lens companies are trying to make it hard to market these "files" for obvious reasons.

[Darryl Meister]

In other words, the freeform process allows a lens designer to go back to the Punktal concept Zeiss introduced in the early 1900s (every Rx had its own particular curvature to reduce marginal astigmatism).

The notion is more or less the same. With the use of complex surfaces, you can also compensate for astigmatism, the position of wear, and -- in the case of progressives -- different regions of the lens. But I want to emphasize that this is not simply "base curve" customization, but a much more sophisticated and generalized approach to optimization, over the entire (global) surface.

The biggest advantage to freeform technology- in my opinion- is the inventory reduction that will result.

From a lab perspective, this would certainly be an advantage. From a wearer perspective, however, a reduction of inventory is irrelevant unless it translates to a price reduction, faster turnaround time, or some other tangible benefit. Customization, on the other hand, delivers meaningful benefits to the wearer, regardless of these other factors.

The question will then become- do the "optimized" lenses provide performance which is superior enough to the "traditional" lenses to justify the extra expense (and delivery time)? For most prescriptions, the answer is probably going to be "no."

Does this statement include Essilor's approach to customized lenses (i.e., Ipseo), or just everyone else's? ;)

Just In Time management

I would hate to call their distribution model "just in time management." This is more of a clever euphemism that a marketing team cooked up for a cost-cutting measure. ;) Dell takes up to a week or more to ship a computer. Any wholesale laboratory could operate with zero inventory, and simply order lens blanks with priority shipping directly from the manufacturer whenever a job was ordered. However, ECPs generally demand faster turnaround time than that.

the other half is developing and maintaining a successful marketplace for a good product.

Ultimately, J&J may increase the progressive lens market through consumer advertising, or at least their own share of it through brand awareness, but they will not increase the market through the introduction of some novel technology with their current approach. As Pete stated, their lenses currently provide none of the potential advantages of free-form (or direct-surfacing) technology, while they undoubtedly suffer from many of the disadvantages, including additional costs and turnaround time.

Best regards,
Darryl

[Pete Hanlin]

Does this statement include Essilor's approach to customized lenses (i.e., Ipseo), or just everyone else's?
Absolutely. As an example of my point, I have a digital thermostat that controls the temperature in my house. It kicks the HVAC on and off according to the times and temps I've selected.

Now, let's say I could have a system that could control the temperature not to the degree, but to the tenth of a degree. Yeah, its a cool concept (pun intended), but the problem is, I am probably incapable of noticing the extra accuracy anyway- so who really cares? If I'm a techno-geek (and I've been so accused), I might point it out to visitors to the house, but I'm not likely to spend a whole lot of extra money on this feature.

The same holds true for a lot of the "customization" we're discussing here. Okay, let's say a toric lens is made atoric (and a number of manufacturers do just this in their customized designs), great! However, there are two factors that limit our appreciation of this accomplishment. First, the benefits of atoricity come in the periphery of the lens. Far enough in the periphery, in fact, that in today's small frames the "areas of greatest improvement" have probably been cut off anyway.

Second, the astigmatism of the eye isn't really all that well organized. Look at a typical topography plot of a cornea with astigmatism and you'll notice it usually isn't all that well "distributed." In other words, the system we're correcting is nowhere near as regular as the correction device we're using.

Am I saying there is no benefit to the fine tuning of base curves, atoricity, asphericity, etc.? Of course not. However, the benefit is not so dramatic as to impact vision to the point where people try the product and say "I just have to have this from now on." AR is such a product. Increase lens transmittance by 6-10% (and take away distracting reflections) and people notice a marked improvement in the comfort of their vision. Marked enough to justify the extra cost the next time around.

Realistically speaking, Varilux Comfort was another example of a dramatic design improvement. Comfort was so remarkably better than Varilux Infinity that sales simply went through the roof (and 10 years later, its STILL the favorite).

There are still cases to be made for improvement of design. Whether the improvement justifies the cost will determine the success or failure of the product. Rodenstock Multigressive was- IMO- way ahead of its time (came out what- five or six years ago). However, delivery was slow, cost was high, and- to be honest- the patients I tried it on weren't overwhelmed (of course, after spending $400 and waiting for a month, you figure these better be the best #*$% glasses I've ever had!).

This reality is no different for Varilux Ipseo. The concept is awesome- customize a design based upon the way the patient actually uses his/her eye and head movements. Based upon the research findings, the result should be a lens that adapts to the patient (rather than vice versa). However, the key will be delivering the product in a timely and cost effective manner- and clearly communicating the use and technical features of the product. In the end, if a patient doesn't actually see better ($100 or so better), there won't be repeat sales of the lens- and all the technology in the world won't matter.

All this to say, there's a reason why virtually all non-aspheric products use 5 or 6 base curves. This has been the level of "customization" that has provided high enough quality to create a balance between cost and performance. Further customization will involve an increase in cost, and the only way to justify the costs is a noticeable increase in performance.

[Darryl Meister]

Now, let's say I could have a system that could control the temperature not to the degree, but to the tenth of a degree.

However, your analogy is an example of precision (how closely we can measure something), not accuracy (how close a measurement is to the desired value).

Since we are talking about accuracy here, a more appropriate analogy would be a thermostat that was off a few degrees. For instance, say whenever you set it to 70 deg you really got 67 deg. If your thermostat was off enough, you would obviously have to go change its setting again to get the desired room temperature. However, with spectacle lenses, the wearer does not have the luxury of turning a dial to get a more accurate power.

And keep in mind that our sense of vision is considerably more "sensitive" than our sense of touch, and certainly makes a more important contribution to our daily lives, so even this analogy undermines the significance of a product meant to improve what most would consider to be our most precious sense.

Lastly, we should not make the mistake of assuming that just because a wearer can tolerate a certain compromise in vision that it is desirable. A typical observer can tolerate up to 0.50 D of power error. Does that mean that he or she wouldn't appreciate, or even prefer, a design with much less? Ignorance may be bliss, but once we see what we are missing, many (if not most) of us would be willing to pay a higher premium -- commiserate, of course, with the gain in performance.

Far enough in the periphery, in fact, that in today's small frames the "areas of greatest improvement" have probably been cut off anyway.

An effective as-worn optimization strategy will generally adjust the power of the lens across the entire viewing zone. For instance, you might very well receive a compensated prescription from the laboratory for a fully customized lens, demonstrating that even while looking ahead you are getting an improvement to the prescription. While the improvement may be small during primary gaze, the point is that the improvements occur immediately, not simply at some far reaching corner of the lens.

Also, keep in mind that progressive lenses suffer from reduced distance and near utility already, unlike single vision lenses. Even small amounts of aberration or power error will interact with the regions of surface astigmatism and mean add power across the lens, which will often shrink the usable viewing zones, or even translate them slightly to different positions. The value of a good optimization strategy comes not from subtle changes in the power perceived by the wearer, but rather from increases in overall utility.

Consequently, viewing zones that would normally shrink in the presence of power errors created by the prescription and the position of wear remain as large and as clear as possible. This is especially important to a progressive lens wearer, particularly in small frames.

Moreover, since we apply this optimization to a lens design made in a high-index lens material, which already suffers from the reduced optics produced by chromatic aberration, it is all the more important to reduce the monochromatic aberrations produced by the lens design. Consequently, a free-form lens design complements high-index materials quite nicely.

Finally, we assess our lenses for distance vision over a +/-30 degree range horizontally and +/-15 degree range vertically, which even small frames will afford. Our near field assessments are also impacted very little by fitting heights (within a reasonable range). In higher prescriptions, the ray-traced fields of acceptable binocular vision increase up to 50% or more when switching from a conventional semi-finished design (SOLAOne) to a fully customized design (SOLAOne HD). I find such numbers rather compelling.

In summary, the wearers will get the largest viewing zones possible for a given prescription. Granted, in some prescription combinations the results may not be as dramatic as others, but the point is that the wearer is always ensured of getting the best performance possible from their lenses, which should certainly be a consideration for premium lens designs, progressive lens designs, or high-index lens designs... Or, in the case of SOLAOne HD, all three.

Look at a typical topography plot of a cornea with astigmatism and you'll notice it usually isn't all that well "distributed."

Still, the overall wavefront reaching the retina can be decomposed into primary spherical and cylindrical elements, which is exactly what an eye doctor does during a refraction (at Essilor, you might refer to this as the 3rd, 4th, and 5th order terms of a Zernike polynomial). The eye is a fixed optical system, and the retina does not move relative to the cornea. So, unless regions of the cornea are deliberately occluded, or you are designing a lens that moves with the eye, the local surface variations across the cornea aren't particularly important.

Realistically speaking, Varilux Comfort was another example of a dramatic design improvement. Comfort was so remarkably better than Varilux Infinity that sales simply went through the roof (and 10 years later, its STILL the favorite).

Keep in mind many would argue that Panamic isn't significantly better than Comfort, yet you still charge significantly more for Panamic. But, more to the point, I am not asserting that optical refinements to a design will produce the same kind of night-and-day differences that moving from a "bad" design to a "good" design will. I am not even suggesting that you can turn a "bad" design into a "good" design using these optical refinements. After all, Garbage In = Garbage Out. I am asserting, however, that you can certainly make a "good" design even better with sensible optical refinements.

All this to say, there's a reason why virtually all non-aspheric products use 5 or 6 base curves.

It may not be entirely fair to assert that our current industry model balances performance with price, particularly since I don't know that many manufacturers decided upon the appropriate number of base curves by wearer studies or anything that scientific. I suspect that inventory requirements have been the biggest consideration. Not to mention the fact that the price a lab pays for a lens blank isn't directly proportional to the total number of base curves made available.

Laboratories must stock dozens and dozens of different lens designs in dozens of materials. Multiply that by 60 (the number of base and add combinations in a typical progressive lens series), then by the quantity of each lens blank the lab plans to keep on hand in order to meet demand, and you have a fairly massive inventory. Consequently, it is in the lab's best interest to carry as few base curves as necessary.

Also keep in mind that astigmats, who account for around 70% of the prescriptions out there, won't really benefit from having additional base curves -- only atoric base curves.

This has been the level of "customization" that has provided high enough quality to create a balance between cost and performance... Further customization will involve an increase in cost, and the only way to justify the costs is a noticeable increase in performance... after spending $400 and waiting for a month

I don't disagree with your point at all.

I think a more appropriate comparison in this instance is the move to high definition television (mainly because I'm into home theater, not thermostats ;)).

Just about anyone who compares a high definition picture to a traditional television picture sees a dramatic improvement. Though, if you would have asked them ten years ago whether their current television broadcasts were "good" or not, they probably would have said "Yes," because they really didn't have anything with which to compare them. But initially the cost for these sets was very high, and the availability of hi-def programming content was limited, so many people held off on buying one when shopping for new televisions.

However, as the prices came down and the availability of hi-def content improved, more and more people switched over to hi-def televisions. I would say the same of fully customized progressive lenses, which initially required high costs and long turnaround times (many still do) -- as you pointed out. Certainly, incremental improvements in vision are still subject to the law of diminishing returns when cost is factored in... But we're not charging $400 for a pair of hard resin progressive lenses, or even making people wait a month for them. ;)

Ultimately, most people will pay more for better vision. But how much more, and for how much better, will of course vary from wearer to wearer. But anyone willing to purchase a premium progressive lens design in a premium high-index lens material with a premium AR coating, would probably be more than willing to invest a little more in order to get a customized lens that offers the best vision possible.

Best regards,
Darryl

[drk]

Darryl,
When will SolaOne HD be available?

[Pete Hanlin]

However, your analogy is an example of precision (how closely we can measure something), not accuracy (how close a measurement is to the desired value).
Actually, my analogy has to do with perception as it relates to both precision and accuracy. Let's use a ruler as an example. My ruler may indeed be inaccurate- perhaps one inch on the ruler is actually 1.0004 inches. However, since my perception is incapable of perceiving the seperation of .0004 inch (approx. 1/100th of a mm), the ruler remains a device that is useful to me. It meets my performance requirements.

Lastly, we should not make the mistake of assuming that just because a wearer can tolerate a certain compromise in vision that it is desirable.
No argument here- however, as the example of the ruler shows, we also shouldn't overestimate the effects hyperaccuracy may have on performance- performance being measured by the wearer.

Consequently, viewing zones that would normally shrink in the presence of power errors created by the prescription and the position of wear remain as large and as clear as possible. This is especially important to a progressive lens wearer, particularly in small frames.
I follow the reasoning, but not necessarily the conclusion. That is, it is fairly easy to calculate the aberrations at different points in a lens (easy, that is, because I have your OpticsLite program- which is a nifty tool). However, experientially (here comes the philosophy degree), even at -4.75 I had a very difficult time noticing a perceptible change in vision when changing pantoscopic, face form, and vertex distance in moderate amounts.

Still, the overall wavefront reaching the retina can be decomposed into primary spherical and cylindrical elements, which is exactly what an eye doctor does during a refraction (at Essilor, you might refer to this as the 3rd, 4th, and 5th order terms of a Zernike polynomial). The eye is a fixed optical system, and the retina does not move relative to the cornea. So, unless regions of the cornea are deliberately occluded, or you are designing a lens that moves with the eye, the local surface variations across the cornea aren't particularly important.
However, the point remains- the eye is not an aberration-free device and there are limits to the perceptual capability of the eye. Meaning, you can place an absolutely aberration-free device in front of the eye and it will still experience visual limitations. Conversely, you can introduce a certain level of aberration that will remain unnoticed below certain levels.

Keep in mind many would argue that Panamic isn't significantly better than Comfort, yet you still charge significantly more for Panamic.
I would actually agree that the jump in visual performance from Infinity to Comfort was probably greater than from Comfort to Panamic. If you owned a Model T and moved to a 1994 Buick Regal the change is going to be more dramatic than when you trade that Regal in for a 2000 Riviera. Varilux Panamic does perform better than Varilux Comfort- and I'm not arguing that SOLAOne doesn't perform better than SOLAMax, or whatever previous generation you wish to compare it to- however, it is a matter of degree.

In the case of Varilux Panamic, I happen to be very comfortable describing it as a better lens, because I dispensed it and the lens performed as billed. There are also non-performance factors which sometimes affect the sales performance of a lens. For example, SOLA Percepta introduced new design concepts (that was the "Prescription by Design" introduced in the 90's, right?). Unless I'm mistaken, however, that design never really sold as well as- say- SOLA VIP. I don't believe the VIP is a better design than Percepta...

It may not be entirely fair to assert that our current industry model balances performance with price, particularly since I don't know that many manufacturers decided upon the appropriate number of base curves by wearer studies or anything that scientific. I suspect that inventory requirements have been the biggest consideration. Not to mention the fact that the price a lab pays for a lens blank isn't directly proportional to the total number of base curves made available.
I would argue that most everything comes down to a balance of performance and price. For example, look at the automotive industry. A Mercedes-Benz is going to have a much tighter standard for things like the gap between body panels than my Chevy Camaro. I guarantee that if I measured my friend's Benz and my car, there would be real differences. I'm also certain GM could probably produce a Camaro (if they still made that model) with gaps every bit as tight as the Benz. However, they certainly couldn't do it for the same price. And so, Chevy will produce cars that have as much quality as they can provide for the price people are willing to pay for cars of the type they make.

Look, heaven knows I am all for technology, optical refinement, and all that. The projects that excite me here at Essilor are the cutting edge, marvels of vision, type stuff. However, we still sell a lot of FT28s and spherical single vision lenses- and there's a reason for that.

The truth is, most of the "traditional" non-customized PALs today are pretty good. Some of those PALs are very good. Can optimization of base curve, asphericity, atoricity, polyvalence, as-worn positioning, prescription by design, and measurement of visual physiology for design (to throw in one Essilor concept) create improvements? Of course they can and do (since some of my job duties involves development of new projects, I sure hope so, anyway). However, for the difference to have a market, it has to be deliverable in a way that is both time and cost effective.

There will always be people willing to spend whatever for the best performance (which is what keeps Mercedes, Ferrari, and Aston Martin in business). However, the vast majority of product will be purchased by individuals wanting the best value- that is, a product that provides the highest perforance at a set price. My argument is- in the market as it is today, the best value is offered by traditional molded and surfaced lenses.

[Darryl Meister]

When will SolaOne HD be available?

As far as I know, it's available now.

Best regards,
Darryl

[Darryl Meister]

Actually, my analogy has to do with perception as it relates to both precision and accuracy.... However, since my perception is incapable of perceiving the seperation of .0004 inch (approx. 1/100th of a mm), the ruler remains a device that is useful to me... we also shouldn't overestimate the effects hyperaccuracy may have on performance

Okay... Then you would have to assume that your level of accuracy is within your level of precision; that is to say, you are assuming that the total error produced by your lens-eye optical system won't be off anymore than your ability to detect the difference. This entire argument rests on the very bold assumption that any combination of unintentional power errors experienced by the wearer while wearing a progressive lens will be within his/her threshold of detection. I'll address this later, since this is a recurring theme in this response.

However, experientially (here comes the philosophy degree), even at -4.75 I had a very difficult time noticing a perceptible change in vision when changing pantoscopic, face form, and vertex distance in moderate amounts.

It is interesting to note that this is precisely why we currently employ averaged measurements for as-worn optimization. Once you optimize the lens for a typical position of wear, small changes don't have a dramatic impact.

However, the point remains- the eye is not an aberration-free device and there are limits to the perceptual capability of the eye. Meaning, you can place an absolutely aberration-free device in front of the eye and it will still experience visual limitations. Conversely, you can introduce a certain level of aberration that will remain unnoticed below certain levels.

I thought your point was directed at the use of atoricity for the correction of ocular astigmatism, but if you were actually referring to the limits of resolution of the eye, I would say that a corrected eye is probably limited more by diffraction and the density of retinal receptors than by the higher order aberrations of its optical system, at least until the pupil size increases enough for spherical aberration to become important.

Nevertheless, to your point, a typical observer certainly has both a detection threshold and a difference threshold for blur (also affected by pupil size). Let's use 0.25 D as a convenient threshold, since it is the basis for refracting.

Here's where I believe your argument starts to unravel a bit... The introduction of any power error will defocus the image, even if the power error is within the detection threshold. Moreover, power errors are additive, so additional power errors will defocus the image that much more. Essentially, you need to remember that you can always make things worse, and it won't take a great deal to make it worse than your threshold. You can always add to a problem that is already present, quickly making it intolerable.

Using your ruler analogy on the additivity of these errors, if your ruler is off by a certain amount, and you are using it to measure a large table, every ruler-length you measure will add that much more error to the final result. Consequently, you won't have to measure long before the final error is well above your precision (ability to detect it). Now, obviously, power errors won't always compound each other systematically, but not many would have to before it becomes an issue.

Moreover, your "it's close enough for me" theory can break down quite quickly, even if you never once experience a single error above 0.25 D, which is already an unlikely proposition. Right off the bat we must assume that, because lenses are only prescribed in 0.25 D steps (+/-0.12 D) and only held to a +/-0.12 D tolerance, you have the potential for up to 0.25 D of error -- your entire threshold -- right out of the gate. So, before we even think about oblique power errors, as worn compensations, toric errors from surfaces with cylinder, or the limitations of progressive viewing zones, we are already potentially sitting at our threshold. Any additional errors will just makes things that much worse.

However, so far, we are arguing over small, potential errors and whether or not the wearer could discern them. What we are primarily concerned about is the global performance across the entire lens in the presence of real optical errors, which can easily exceed 0.25 D. Let's take a look at some real scenarios, instead. So, allow me to demonstrate my point and hopefully put to rest your doubts about the potential benefits of full optical customization when applied properly. ;)

The series of plots, below, demonstrate the ray-traced optical performance of a typical progressive lens design in a +2.50 Add, across a range of prescriptions. (A design you are undoubtedly very familiar with.) Now, the green contour line represents our 0.25 D detection threshold, while the red contour represents a threshold of 0.50 D, representing acceptable vision.

Note that 1) I haven't even looked at threshold levels you would consider irrelevant, 2) These plots assume that the lens was prescribed and surfaced with absolutely no error, and 3) I haven't adjusted any of the as-worn parameters between plots, which would further affect blur. Consequently, all of the changes in blur you see are simply the result of optical power errors produced by the prescription. I have even included a smallish frame as a reference point.

Blur Field for an Emmetrope
Using Recommended 5.00 Base


Blur Field for a Low Myope
Using Recommended 3.50 Base


Blur Field for High Compound Myopic Astigmat (X 180)
Using Recommended 3.50 Base


Blur Field for High Compound Myopic Astigmat (X 045)
Using Recommended 3.50 Base


For convenience, I used an implied object field from optical infinity at the distance reference point of the lens, down to a 40-cm working distance through the near reference point. While your specific ray-tracing assumptions will vary the look of the plots, you will see the same basic trends.

The purpose of these plots is simply to demonstrate how the utility of the lens design and regions of blur are affected by the prescription, even for the same base curve. I think you would agree that the Emmetrope wearer enjoys a rather generous range of vision over the lens, while some of the more extreme prescriptions result in noticeably restricted fields of clear and usable vision.

Ultimately, the purpose of optical customization is to ensure that all wearers get the maximum optical performance possible from the lens design, as well as the same generous zones of vision. Consequently, that compound myopic astigmat can get the same (or at least nearly the same) level of performance as that emmetrope, and they can both get the best performance possible.

SOLA Percepta introduced new design concepts (that was the "Prescription by Design" introduced in the 90's, right?). Unless I'm mistaken, however, that design never really sold as well as- say- SOLA VIP.

Yes, but that's not because wearers feel that VIP is better -- or even comparable -- to Percepta, but rather because of the very significant cost difference involved.

I would argue that most everything comes down to a balance of performance and price... A Mercedes-Benz is going to have a much tighter standard for things like the gap between body panels than my Chevy Camaro... And so, Chevy will produce cars that have as much quality as they can provide for the price people are willing to pay for cars of the type they make... However, they certainly couldn't do it for the same price.

Wasn't this really my point all along, though? If it makes you feel any better, think of SOLAOne HD as a Mercedes, only considerably less expensive and with better gas mileage. ;)

And you make another interesting point that I had alluded to earlier... You now speak of the balance of performance and price in the context of different tiers of performance for different price points (e.g., Chevy versus Mercedes). Before you seemed to be speaking more generally of the balance between price and performance, as if it applied to all lenses and all consumers, universally. I interpreted your post to suggest that there is no market for added optical performance if it comes at a cost, unless the difference is night-and-day.

But, of course, that would suggest that there is no market for Mercedes Benz in your auto industry analogy. After all, tighter body panel tolerances and other refinements may not mean much to the average consumer, but they certainly would to the average luxury car buyer.

As I said, when discussing premium lens designs in premium lens materials with premium lens coatings, we are obviously referring to the next level of performance, though I believe your comments are more relevant to the commodity progressive lens market. And it's equally important not to lose sight of the fact that SOLAOne HD is currently a 1.67 high-index product. Many ECPs will buy the lens because it is a premium high-index lens design; for them, the optical optimization is just an added benefit.

However, for the difference to have a market, it has to be deliverable in a way that is both time and cost effective.

Do you feel that SOLAOne HD isn't time- or cost-effective for some reason?

My argument is- in the market as it is today, the best value is offered by traditional molded and surfaced lenses

I don't know that your premises have actually surported this conclusion, but we make those lenses, too... So I guess we offer both the best value as well as the "finer things in life" for those willing to pay a little more to have the very best. ;) But, seriously, we don't expect everyone to buy SOLAOne HD in 1.67. We do, however, want those who do buy it to get the most for their money.

Best regards,
Darryl

[Pete Hanlin]

This entire argument rests on the very bold assumption that any combination of unintentional power errors experienced by the wearer while wearing a progressive lens will be within his/her threshold of detection.
The argument rests on the not-so-bold assumption (based on experience) that most patients are capable of receiving very satisfactory performance from one of the traditional PALs currently on the market.

You can always add to a problem that is already present, quickly making it intolerable.
Of course, and the ability to fit the atypical patient with eyewear that meets his/her special needs is what seperates the "frame sylist" from a fully trained Optician. However, the majority of patients walking through the door have distance ametropias involving relatively low amounts of myopia and/or astigmatism- with a percentage of hyperopes mixed in just for fun. For these patients, vision through traditional PALs is not only "tolerable," it is quite functional and acceptable- especially when they use advanced PAL designs like Varilux Panamic, Gradal Top, or perhaps SOLAOne (even in its "non-customized" CR-39 form).

The purpose of these plots is simply to demonstrate how the utility of the lens design and regions of blur are affected by the prescription, even for the same base curve. I think you would agree that the Emmetrope wearer enjoys a rather generous range of vision over the lens, while some of the more extreme prescriptions result in noticeably restricted fields of clear and usable vision.
As a pre-eminent Optician who writes extensively on ophthalmic optics once said, "Contour plots, although a useful tool for analyzing and comparing the optics of a progressive addition lens, are simply mathematical models of the lens surface. Although they may be indicative of lens performance, they are not enough to predict patient acceptance." In this case, you have posted "blur field plots." Although you don't list the exact powers of the lens, I've fit numerous myopes of moderate to high correction- some with cyl- who seemed extremely happy with their zones of vision with Varilux Panamic (which was my lens of choice when I quit dispensing and came to Essilor two years ago). In my final six months of dispensing, we were converting patients from our previous lenses of choice (two different designs), and it was interesting to see the "Global Design Management" of the lens at work.

Sounds like a cheesy testimonial, but when converting patients from the one design we used, I'd just ask them if they'd like to get rid of the swim in the bottom of their lenses. For the ones who actually noted that the swim did bother them, the Panamic was always an improvement. Now I can come up with all kinds of cool looking graphs and plots to explain why that's the case, but I was a LOT more impressed hearing it from wearers.

Moreover, your "it's close enough for me" theory can break down quite quickly, even if you never once experience a single error above 0.25 D, which is already an unlikely proposition.
I think you are misunderstanding my take on advanced design. If I could wave a magic wand, I'd like everyone to have lenses which are truly customized not only to reduce the aberrations associated with correction of their ametropia- but also to the visual habits ingrained into them over the 40+ years they have been viewing the world (which only Varilux Ipseo does ;^). It would also be marvelous if everyone could benefit from materials perfectly matched to their particular needs (and for the sake of argument, let's throw AR on there and polarization on all those second and third pairs I'd love them to have)...

Yes, but that's not because wearers feel that VIP is better -- or even comparable -- to Percepta, but rather because of the very significant cost difference involved.
Ah, but there's exactly my point... all of these wonderful things cost money. I'm not even saying they cost too much money (after all, we're talking about the equipment they will use to see the world over a one or two year span), however, the truth is they often cost more money than people are inclined to spend.

Look, I wish all the success in the world to SOLAOne HD (well, not as much success as I'd wish for something like Varilux Ipseo, but you get my point). Likewise, I'd love to see the US Market filling more than 8% of Rx lenses with high index, 20-30% with AR, and 50-60% of presbyopes with PALs. Also, I believe these trends will continue to go up over time. If SOLA can figure out how to move tons of people into a higher market quickly, there are a lot of companies that will be interested in learning your secrets. Varilux and Crizal have been growing the upper-tier market for years, and its a slow- if profitable- road to travel. (Yes, of course other companies, including SOLA, also grow the upper-tier market with their own products, like SOLAOne HD and Teflon, but its a long road.)

Adding to the slowness is the state of our market today. Many dispensers are attracted by the $5 and $10 spiffs being doled out by various manufacturers. Who can really blame them? If I were still making $9-10 an hour dispensing glasses in PA, that extra money would probably look pretty good. All that to say, for every boutique optical out there selling $600 eyewear routinely (and I've toured many of these shops- they're awesome), there are four or five shops out there selling PALs at $139-179 (and I've worked in several of these places- they are quite capable of producing good eyewear that people are very satisfied with).

Additionally, our field is not consistently educated. One of the obstacles Varilux Panamic has encountered is the imprecision with which eyewear is commonly fit in the US Market. I'm not trying to offend the American Optician, but when I visit a lab and notice that over 30% of the PAL orders have binocular PDs, its not hard to see why a design with a design which particularly benefits from a precision fit sometimes encounters problems. Likewise, the level of refinement we have been talking about goes out the window if eyewear isn't being fit properly.

So, to sum- all the design features you describe are great. I love reading about them (and working with them in-house here at Essilor). Without a doubt, we are capable of producing a lens that is better than what the average person is wearing today. Within that statement is part of the problem, however. We can create a lens, we can even create several thousand lenses... After taking a recent tour of a lab facility in Europe that produces over 8,000 pair of lenses a day, however, I'm not convinced freeform technology is ready to produce advanced lenses for the masses just yet, however.

That doesn't mean we shouldn't keep slugging our way down the road- or that these new designs aren't fabulous for the few percent of patients who will spring for them. It does mean, however, that you have to temper the "great new design" stuff with a reality check now and then, and take into consideration that most patients are rather happy with their vision today. For anyone who has ever tried to sell new eyewear to a patient the doc has just told "still sees 20/20" out of their current pair, you are familiar with the problem.

PS- On that note, I highly recommend the book "20/20 is Not Enough." Great discussions on the finer aspects of vision we don't often measure or correct.

[Darryl Meister]

The argument rests on the not-so-bold assumption (based on experience) that most patients are capable of receiving very satisfactory performance from one of the traditional PALs currently on the market.

But that wasn't your original argument, was it? If I recall, your original was point was that the performance differences were indiscernible because the eye couldn't measure them (power differences were generally within the precision of the optical system of the eye).

Stating that people could accept or tolerate performance limitations is an altogether different argument, and I don't disagree with your point here at all. After all, most states require a visual acuity of only 20/40 in order to drive without corrective lenses, which is equivalent to roughly 0.75 D of power error. So the government has decided that the typical person can not only tolerate that much error, but still operate a motor vehicle as well. (And, hey, as long as I'm not in the car with him/her... :))

Not to mention the fact that people received satisfactory performance from VIP and Adaptar... Does that mean we should stop trying to make better lenses? Should Intel have stopped at the 8088 chip or Ford at the Model T you mentioned earlier?

I will actually cite your earlier point concerning the balance between performance and cost here. However, that balance is dictated by consumers, not manufacturers.

the ability to fit the atypical patient... However, the majority of patients walking through the door have distance ametropias involving relatively low amounts of myopia and/or astigmatism- with a percentage of hyperopes mixed in just for fun.

Yes, but keep in mind that SOLAOne HD is a 1.67 high-index lens, which is often the first material of choice for those "atypical" patients. Also note, from my comparisons above, that even a 1.50 D myope loses some performance relative to the emmetrope. Consequently, optical optimization can be beneficial to just about any wearer. Though, as we've agreed, for lower powers, the choice to achieve incremental gains in performance using a premium lens will obviously depend upon the individual wearer.

Contour plots, although a useful tool for analyzing and comparing the optics of a progressive addition lens, are simply mathematical models of the lens surface. Although they may be indicative of lens performance, they are not enough to predict patient acceptance

And I still stand by that. Keep in mind that:

1. I didn't provide contour plots of the lens surface, which is specifically what that statement is referring to; I provided ray-traced optical plots of the object-lens-eye system.

2. I made no statements regarding patient preference or acceptance, but simply demonstrated how the optical performance of the lens changes in the presence of real prescriptions. This is measure is strictly quantitative, not qualitative.

Although you don't list the exact powers of the lens, I've fit numerous myopes of moderate to high correction- some with cyl- who seemed extremely happy with their zones of vision with Varilux Panamic (which was my lens of choice when I quit dispensing and came to Essilor two years ago).

I prefer not to make anecdotal claims, particularly since I do work for a manufacturer. Having been a dispensing optician once, myself, for six or seven years, I can easily claim to have fitted this SOLA lens or that, with unparalleled success, but many people would probably fail to see any objectivity in such a statement. And, the truth is, I had success with a lot of different lenses from a lot of different manufacturers, including Essilor.

And the powers of the lenses are Plano for the emmetrope, -1.50 DS for the low myope, -3.75 DS -2.00 DC (at both 180 and 045) for the compound myopic astigmat.

Sounds like a cheesy testimonial

Just a little. ;)

Now I can come up with all kinds of cool looking graphs and plots to explain why that's the case, but I was a LOT more impressed hearing it from wearers.

Likewise, I can post literally dozens of SOLAOne testimonials (I have a file of them around here, somewhere). But that's not the kind of argument I'm trying to support.

The final performance of a product on a population of wearers is obviously paramount. However, and I realize that this is not the case with Essilor, when the merits of your product rely solely on your ability to get positive feedback from some consumers (which isn't entirely difficult), and not at all on demonstrating the actual differences and technical merits of your product, you have moved your marketing into the realm of late-night television advertising.

And it's important to realize that you can't design a lens using a "Wearer Feedback" merit function. If you create a prototype design and test it on a small wearer population during a developmental trial, you still need to assess some sort of optical characteristic before you can refine it any further. Otherwise, you would have no idea as to why the wearers did -- or did not -- like a particular design, which leaves little room for improvement.

Lastly, since you are basing your argument on wearer trial results instead of optical differences, unless you've tested a fully optimized version of Panamic on a population of wearers, and determined that there is no statistically significant forced-choice preference for the optimized design, can you really make a claim one way or the other on the basis of wearer preference? Do you know that wearers wouldn't prefer an optimized Panamic?

and for the sake of argument, let's throw AR on there

No argument here.

Ah, but there's exactly my point... all of these wonderful things cost money... however, the truth is they often cost more money than people are inclined to spend.

I didn't think that was ever a point of contention. However, you're certainly welcome to have any Varilux Panamic wearers who feel that they are paying too much for progressive lenses to switch over to the incredibly affordable SOLA VIP. ;)

I doubt that this was your intention, but my understanding of the underlying point in your argument is that (you feel) Panamic is worth the extra $$$ over Comfort to most people, for reasons that have not been clearly defined, but that SOLAOne HD in 1.67 is not?

Yes, cost is obviously a factor, but I haven't argued against that. But I don't know that you've provided any evidence that these newer, better designs cost too much, although you've frequently alluded to that fact (at least for the non-Varilux designs, like SOLAOne).

I understand your point regarding the balance of performance and price, but I think you might be arguing against SOLAOne HD in the context of hard resin progressives, not 1.67 high-index progressives. Certainly, incremental gains in vision may not merit a super-expensive product for most people, but SOLAOne HD in 1.67 is not a super-expensive product, particularly in the context of 1.67 premium progressive lenses. And the gains in vision for some people may be rather significant.

If SOLA can figure out how to move tons of people into a higher market quickly, there are a lot of companies that will be interested in learning your secrets.

Haven't we derailed this Definity thread enough, already? ;)

Without a doubt, we are capable of producing a lens that is better than what the average person is wearing today.

Your earlier responses led me to believe that you feel as though modern progressive lenses could not be improved enough for wearers to actually notice...?

It does mean, however, that you have to temper the "great new design" stuff with a reality check now and then, and take into consideration that most patients are rather happy with their vision today

This gets back to my earlier points: People are seldom dissatisfied with current technology. They weren't that dissatisfied with Natural before you introduced Ovation, they weren't that dissatisfied with Comfort before you introduced Panamic, they weren't that dissatisfied with Nintendo 64 before Nintendo Gamecube, they weren't that dissatisfied with Windows 6.1 before Windows 95, they weren't that dissatisfied with analog televisions before high-definition televisions. And so on.

The fact is, technology will continue to evolve. And, while people may be "satisfied" with the current limits of technology, they generally embrace newer, better technology with open arms... Because it is better. Until you -- or anyone else -- has seen how good something can be, it is often human nature to live with it as it is. Sort of like the expression, "Don't know what you're missing." And, more often than not, they are perfectly willing to pay a little more for it.

Pete, ultimately, I understand that the major manufacturers all make pretty good products. Sure, some may be better than others. And I also consider both Panamic and Comfort to be great designs. The fact is, traditional progressive lens design is starting to reach somewhat of a plateau. You just can't make the basic design of a well-performing, traditional progressive lens that much better, which is a point I think you would echo. However, refinements and customizations allow us to further improve the design, once a given lens design has started to reach that plateau of perfection.

Customization allows us to deliver the best performance possible. Better and more meaningful forms of customization allow lens manufacturers to differentiate their products and offer wearers truly unique optical solutions. A fully customized design allows us to close the gap between lens design technology and the individual wearer by designing a lens specifically for the wearer. And keep in mind that we have discussed mainly full optical optimization, which is only one element of customization.

Customization has always played a vital role in the evolution of progressive addition lens designs. Essilor is well aware of this, since -- to the best of my knowledge, at least -- they introduced the first asymmetric design (customized by eye) and the first multi-design (customized by add power). You have even recently embraced customization by frame style with the new Ellipse lens. You are also pursuing customization by various biometric parameters with Ipseo.

Consequently, I am not entirely sure why you would argue against forms of customization simply on the basis that "most people are satisfied with what they have now," or even on the basis that fully customized designs may cost a little more (and I suspect Ipseo will be priced higher than Panamic).

Sure, progressive lens designs will continue to improve incrementally, but various forms of customization will also allow us to achieve improvements in performance for the wearer -- in some cases, perhaps even greater improvements in performance than the incremental changes in lens design can offer.

Best regards,
Darryl

[Pete Hanlin]

In the interest of avoiding carpal tunnel syndrome, I'll just respond to one segment, because I think it goes to the heart of where I think we may be differing in our approach to the discussion...
Consequently, I am not entirely sure why you would argue against forms of customization simply on the basis that "most people are satisfied with what they have now," or even on the basis that fully customized designs may cost a little more (and I suspect Ipseo will be priced higher than Panamic).
I'm not intending to argue against customization as a tool to improve the optics of a lens. What I intended to discuss in this thread from the start is:a.) all "freeform" lenses aren't customized, b.) "customization" doesn't always create a better lens if the design is poor, and c.) "customized" lenses are unlikely to replace traditional molded and surfaced PALs anytime soon. I still see no reason to doubt any of these three points.

You are stating that SOLAOne HD- with "as worn" customization- represents an improvement in optical quality when compared to "non-customized" PALs. Assuming the lens is fit and fabricated properly, I offer no reason to doubt this assertion. However, as numerous examples from both our companies demonstrate, better optics don't always result in the market's embrace of the product- there are other factors to consider.

Perhaps one day- when I'm wearing PALs- I will try on a pair of "as worn customized" lenses vs. a pair of well-designed "traditional" PALs and will experience an epiphany. Until then, I'll remain slightly skeptical regarding the translation of ray-tracing benefits to actual wearer benefits.

[fvc2020]

This thread was quite interesting and I actually followed most of it, but I have one question.


What is SolaOne HD? I have a Solaone which I don't wear because I see better out of my Panamics, so what's the big deal?


Christina

[Darryl Meister]

What I intended to discuss in this thread from the start is:a.) all "freeform" lenses aren't customized, b.) "customization" doesn't always create a better lens if the design is poor, and c.) "customized" lenses are unlikely to replace traditional molded and surfaced PALs anytime soon.

And I certainly agree with all of these points.

You are stating that SOLAOne HD- with "as worn" customization- represents an improvement in optical quality when compared to "non-customized" PALs.

Specifically, I am stating that a lens fully optimized for a given prescription (in the as-worn position) will deliver better vision than the same design in a semi-finished form. We should be careful to distinguish between simple as-worn compensation and optical optimization of the design for a given prescription in the as-worn position. But, to your earlier point, the differences in performance between the fully-optimized and semi-finished designs will become more pronounced as the prescription deviates from the "optimal Rx" of a given semi-finished lens blank.

However, as numerous examples from both our companies demonstrate, better optics don't always result in the market's embrace of the product- there are other factors to consider

I agree with that one, too.

Until then, I'll remain slightly skeptical regarding the translation of ray-tracing benefits to actual wearer benefits.

It's just a more accurate means of modeling the optics of a lens. Unfortunately, it's nothing terribly new and people have been doing it since the dawn of optics. (Though many manufacturers have just recently started using it for progressive lens design.) In precision optics, for instance, everything is based upon ray-traced calculations. The aspheric lenses you guys use, and the aspherized distance zones of your flatter progressives, were probably also based upon the mathematics used for ray tracing (if they weren't optimized using ray tracing in the first place).

So, getting back to Definity... ;)

Best regards,
Darryl

[Darryl Meister]

What is SolaOne HD? I have a Solaone which I don't wear because I see better out of my Panamics, so what's the big deal?

SOLAOne HD is a 1.67 high-index version of SOLAOne with full optical optimization. (You can read some of the posts above for a detailed discussion on optical optimization.)

As far as "seeing better" through one or the other goes, that statement is a bit vague, so I don't know that I could give you any specific advice, other than to ensure that the lenses were fabricated and fitted correctly.

Best regards,
Darryl