# Optical Forums > Progressive Lens Discussion Forum >  Progressive Lens Design: Where do we go from here?

## Steve Machol

What's new in the world of Progressive lenses?  Are there any truly revolutionary concepts yet to be discovered, or has this technology reached its practical limits?

Let's see your thoughts on this subject.

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## chip anderson

Away from them and back to the glass panafocal!  Where else but to go backwards and call it a new discovery?

Chip:hammer:

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## Carol D

I would like an "occupational progressive" similar in function to the double segs we use for mechanics and electricians. I want a LARGE central distance target with a mid-range and near beneath and a large intermediate above. Something useful for pilots, mechanics, people running large commercial printing presses, etc..
Not like the old AO technica or the Overview.  Anybody got something in the works?

Carol D

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## John R

I'm pretty sure that there are plenty of new designs waiting to be brought out. The main problem at the moment is saturation there are too many diffrent suppliers with very similar products.
As Carol has said there are plenty of people who could use diffrent designs for their jobs but would there be a big enough market for it.
Maybe a casting system that would allow you to specifey your own lens design.

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## Steve Machol

While an 'occupational progressive' is certainly an interesting option, I was more interested in whether or not you think that the 'standard' Progressive len designs can be improved, and if so, how?

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## Joann Raytar

A standard progressive with the intermediate and near widths of one of the office lenses wouldn't be a bad creature.  I am not sure if that wouldn't cause too much distortion in the distance though.

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## Jackie L

Every time a lens manufacturer boasts a wider intermediate and near, another comes along that is even wider.  The Western World demands it.  Aaahhh, just imagine a PAL lens design with full fields in distance, intermediate and near vision.

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## Steve Machol

But the nature of the beast is that when you make one of the zones wider, you have to give up something elsewhere.  For this reason I wonder if we've reached the practical design limits for PALs.  Physics seems to dictate that not much more can be done, other than redistribute the unwanted astigmatism in new ways.

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## Joann Raytar

I know Enigma SV didn't fly but one of the reasons was the Rx limitations.  Is there a reason why the technology behind Enigma couldn't be applied to a PAL?  If Enigma was available in a PAL, we probably would have moved them in a snap.

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## judyseyes

Steve

New equipment is on the horizon which will customize RX based on PD, seg height, vertex, as well as RX.  Semi-finished lenses will become "hockey pucks", much like Gas Perm Buttons.  No more backorders! Also, endless options for materials.  Patients will benefit by having a more precise finished product, and ECP's will benefit by having better replication through their labs.  Every manufacturer is searching for new ways to capitalize on baby boomers.  ;)

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## Steve Machol

By the vote, a lot of people think that more can be done with PAL designs.  However, except for variations of current design concepts (and Jo's interesting Enigma PAL idea) I don't see any truly new ideas concerning progressive *lens designs*.  

I knew I shouldn't have made this into a Poll.  The problem is that people just vote and don't post.  :p  

If you voted that you think much more could be done with PAL designs, please post telling us what your thoughts are.

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## Specs

I think that your comment that not much more can be done, is perhaps true with the technology of fabrication that is available today. However, not true for our future.  I bet the Ben Franklin light bulb was about as good as technology allowed at that time. Now we have UV bulbs, flourescent lights, grow lights, natural full spectrum bulbs, mercury vapor bulbs, sodium bulbs, even randomly blinking Christmas lights, etc, etc. Our industry won't stand still either. The technology may not be right around the corner, but I guarantee you that the progressives will improve in all of the obvious areas, reading width, peripheral distortion, etc. Our progressives of today will one day be antique designs. As in most industries where there are substantial dollars to be made in capturing a decent size of a market, there will always be someone trying to build a better mouse trap. In this case a progressive lens. Mark my words, we may or may not see it in our lives, but it will happen.

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## Steve Machol

It's not the technology that is the limiting factor - it's the laws of physics.  After all, PALs are largely designed on the computers these days and computers aren't constrained by manufacturing technologies.  The truth is there's is only so much than can be done by manipulating the surface.  

Now if you're thinking of alternate materials and indices, then _perhaps_ something can be done.  However even in this case the optics  will be constrained by the laws of physics.

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## Joann Raytar

We are all thinking in terms of front surfaces, I believe.  What about the new Johnson & Johnson lens?  From what I understand that lens design involves doing something different with the back surface.  What differences does altering the back surface make?

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## Steve Machol

> *Jo said:* 
> What differences does altering the back surface make?


Good question.  Other than being an interesting concept, does this really provide any optical benefits?  And if so, what are the advantages and how significant are they?

To my knowledge many, if not the majority, of PALs sold today are lenses that were designed more than 10 years ago.  For most people, these lenses work just as well as newer designs.  Why is that?

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## Alan W

I don't think Smart Seg Technology has been fully explored. And, with the advantage of lathe/3 axis/and "needs based" designs, I am convinced that what we see as a progressive lens "all in one" may someday give way to more customized lenses.  The computer programming part . . . Computer Aided Lens Design and Manufacturing that can drive high tech machines seems in my mind to be the area we have not seen nearly the likes of.

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## Ron

:Eek:  Check out the CFL-atoric progressive lens from Optical Dynamics.  It's molded and is very high tech.  Only molding can produce a double sided aspheric lens and it's available today.

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## Steve Machol

> *Ron said:* 
>  Check out the CFL-atoric progressive lens from Optical Dynamics.  It's molded and is very high tech.  Only molding can produce a double sided aspheric lens and it's available today.


But what exactly are the advantages of a double-sided aspheric lens?

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## Alan W

I would like to see more about the lens. 
I think a closer look at 3 axis motion control computer driven lens making may reveal how a mold is made. 
The Schneider Generator from Zeiss is in use in 5 locations here in Houston. I have contacted three of them and saw one system. It can do anything and creates back surfaces exactly as the computer design instructs it to do . . . aspheric, parabolic, etc. In fact , it creates back surface progressives using programming technology that is well regarded. I think we both will agree that back surface progressives have some fine advantages.
Nevertheless, there's room for all kinds of new technology. I just wonder, and would like to know what the economics are. So, if you have some additional information in that regard, please, by all means share it.  I can be reached at:

specsupport@ev1.net

Thanks

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## harry a saake

:D My thoughts are until we relate all aspects of any refraction and fitting, some of the best designs may not work as planned. First we must have phoropters that are more conducive to how a patient sees with there glasses. No one sees out of a pair of glasses the way they see through a phoropter.
......Next has to be how the actual frame fits on the patient. Until you know what the as worn postion of the particular frame is, how do you decide on a lens design.
..... Also, until vertex distance is measured from cornea to back surface of the lens, how do you compensate,especially with your high rx patients.
...... In summary, i think until we change the way we do things, and do each on a custom basis, we will never be as good as what we could, and the best lens designs in the world will not work as they could.

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## Clive Noble

Yes, I'm sure there can be ways to better the way the over 40s can see,  but rather than tackling it by trying to improve Progressive Lens Design, which we've all agreed may have reached a peak at present, maybe we should be looking at the problem from a different perspective..... it's called 'lateral thinking'

We've all seen over the years how TV manufacturers have attempted to get better and more efficient designs for the 'tube'
I don't think it can get any better today.
I can recall in the 50s, we had the tube of our tv overhauled then replaced, it was the regular thing to do in those days after a couple of years use.

In a few years time, the regular tube will be a museum piece, as will the glass monitor for the computer...... a bit of lateral thinking has produced the Flat Plasma Screen.

So, let's go away from the idea of how to design a better lens, think laterally, the ultimate goal is how to give the patient clear vision from 30 cm to infinity.

I wish I could come up with an answer!

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## Alan W

Years ago someone invented a device that stimulated nerves on the back in a pattern that emulated what a camera saw. It was for blind people.

Then, someone invented a device that was implanted in the ear and stimulated the nerve directly, a cochlear implant. For the hard of hearing from nerve damage or insufficiency.

What's the dudes screen name on Star Treck who's blind without those Maui Jim cool looking ocular nerve stimulating type framastinger doodads?

We need to develop a CCD, like muchomegamegapixels, in a contact lens format with a microwire that goes around to the back of the eye and stimulates the ocular nerve. It can be controlled by cerebral signals like an artificial limb.  Made by Kodak . . . OK . . . Olympus! Comes with lifetime supply of conductive Liqui Tears.

Damn . . . . I gotta run down to Radio Shack. If I'm not back in 1/2 an hour, call Steve M.

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## Alan W

PROBLEM:   You can no longer eat potato chips cause the sharp edge might sever the microwire.

ADVANTAGE: The conductive Liqui Tears can also be used with a defibrillator.

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## Texas Ranger

All studies indicate that the three most important factors of pal fitting are 1. the fitting skills of the optician, 2. the prescription, and 3. the lens design. From a "fitting skills" aspect, I think that monocular pd's and monoc. seg hts are critical, so is expertise in frame styling for the proper depth of lenses to accomodate pals, not redesigning pals to accomodate too shallow frame styles. 2. when I see an rx in plus cyls, I cringe. I believe plus cyl phoropters cause a great too many rx problems, and it is impossible to imulate the that eye exam with minus cyl lenses, and it's made even more difficult for presbyopes since you cannot compensate for their axis rotation at the near level in glasses that cannot be duplicated even in a trial frame. After fitting four generations of pals, I think the new ones are the best, but they are more "all-around" wear better. we need to do a better job of educating folks about the need and availability of specialty lenses, like for the computer, etc. per capita spending for eyewear lenses in america is about 1/6 of what we spend on shoes....people just tend to think something on their feet is more important than what's on their face, pretty sad..... so, MD's, get rid of those out-dated plus cyl phoropters! that's a start...

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## Steve Machol

I think the suggestions on fitting techniques for PALs is one area of potential improvement.  However in spite of 15 votes stating that 'much more could be done' with PAL designs I still haven't seen a single response that indicates what exactly that is.   :Confused:   Perhaps I worded the question poorly.  

Let me ask it another way:

What PAL lens is the current 'State of the Art' and why do you think so?  In particular, what optical advantages does it have over older designs?

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## Pete Hanlin

New equipment is on the horizon which will customize RX based on PD, seg height, vertex, as well as RX. Semi-finished lenses will become "hockey pucks", much like Gas Perm Buttons.
I'm convinced this statement pretty much sums it up.  People love to personalize products to themselves (one survey showed 37% of people were willing to pay 20% more for a product that was customized to their particular needs).  

In the future, I think the patient will be able to specify the softness, progression curve, and position of the channel by answering a computerized survey of their particular visual needs.

What PAL lens is the current 'State of the Art' and why do you think so? In particular, what optical advantages does it have over older designs?
I'll say the Panamic is current state of the art, even though I believe there are some Hoya and Rodenstock products out there that are more advanced.  I'll use the Panamic as an example, however, because it is widely used and has a number of features that represent the new generation of PAL (e.g., multi-design based on both base curve and add power, positional symmetry between the eyes which produces better binocular vision, etc.).  I'm not positive if the Panamic uses "as-worn" optimization, but that's another advancement that deserves note (I know Pentax's lens is designed with fitting characteristics in mind).

To sum, I think we've gone about as far as we're going to with current materials and "stock" SF lens blanks (although this weekend our Hoya rep was touting some "sensational" new PAL that is supposedly "far beyond" the Panamic... we'll see).  Further development will probably come as suggested earlier- through customization to the patient.

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## Ron

Steve, if you minimize the distortion on the cylinder side, the lens will be very easy to adapt to and be thinner.  Also if the lens is molded, there are no surfacing marks that reduce light that goes thru the lens.  There are several more reasons but those are 2 real good ones.

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## Steve Machol

> *Ron said:* 
> Steve, if you minimize the distortion on the cylinder side, the lens will be very easy to adapt to and be thinner.


Honestly I don't follow this at all.  Can you elaborate?  What are the optical principles involved?  Of course whenever you can minimize distortion, optics improve - that's a given.  But one of the main features of PAL lenses is that when you minimize distortion in one area it has to go somewhere else.  You can compress the distortion into smaller areas, but then you move closer to the older 'hard' designs like AO UltraVue and Younger 10/30.  You can also spread the distortion out which then brings you closer to the more recent 'softer' designs.  (At this point it would be interesting to get Darryl Meister's input on this issue.)




> Also if the lens is molded, there are no surfacing marks that reduce light that goes thru the lens.


Sounds good in principle, but again what are the practical benefits?  Assuming that we are talking about a properly surfaced lens, are 'surfacing' marks measurable and in any way noticed by the human eye? What clinical studies support this conclusion?   Also most surfaced lenses are backside coated.  What effect does this fact have on this claim?

Don't get me wrong, I'm not picking on you.  But it seems to me that there are very few actual clinical studies and wearer trials being done today to support the myriad of claims being made about the optical benefits of one product over another.  Food for thought! ;)

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## Pete Hanlin

It looks like you guys are in the same Arizona town, so you should discuss PALs over a cinnamon bun and coffee some time!  

All the hype aside, Steve has a point.  Facts are, in a PAL you have to get from point A (the distance Rx) to point B (the near) without the aid of a segmented line.  Getting rid of that line causes distortion.  You can cram all the distortion into the tiniest space possible (basically a blended lens), or you can spread it out evenly as possible all over the lens- but it will always be with us.

I suppose you are speaking of atoric or aspheric ocular (back surfaces), which is already being done by a number of manufactuers (e.g., Rodenstock's _Multigressive_).  Are the newer designs more comfortable to wear?  According to the patients who I've switched from VIPs to Panamics, the new design works much better. Does each and every new design we see really usher in a grand new concept in vision?  Of course not. 

My theory is that the key to success with _any_ PAL (new or old) comes down to the expertise of the fit.  I like to think of the corridor as a keyhole.  Center that key hole as close to the eye as possible, and you'll have good vision.  Slap it haphazardly in front of the eye and you'll get the whole gambit from "works fine" to "can't see a thing!"  Sure, use the best designs out there (Panamic, SolaMax, LifeC, etc.), but realize that PALs are like golf balls- some have the _potential_ to go farther and  straighter than others, but you still have to hit the dang thing just right to make it work!
 :Cool:

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## Joann Raytar

According to the Enigma website, they are planning on rolling out a PAL they just don't have an available date.

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## sandeepgoodbole

> *Steve Machol said:* 
> I think the suggestions on fitting techniques for PALs is one area of potential improvement.  However in spite of 15 votes stating that 'much more could be done' with PAL designs I still haven't seen a single response that indicates what exactly that is.    Perhaps I worded the question poorly.  
> 
> Let me ask it another way:
> 
> What PAL lens is the current 'State of the Art' and why do you think so?  In particular, what optical advantages does it have over older designs?


Just ignorant about this thread, 10 minutes earlier I have asked 
a Q about pals. That Q itself has a suggestion which I think could be the Potential Improvement : 
Instead of "Corridors"  : "Rows "of progression would be making them much better. :cheers:

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## yzf-r1

:idea: 

if a PAL was intended to be a 65mm uncut, would it not be possible to design it as though it was going to be say a 80mm uncut, then the distortion would be not only be far out in the periphery, in fact it would all be edged off, and you would end up with THE perfect progressive lens.

I know, i know, it sounds so daft, furthermore if it was possible someone would have already thought of it.  All you lab rats and lens experts will post and tell me that it is not possible, but what i want to know is why not???

yahya

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## myodisk

Sola came out (very boldly) with the "Smart Seg" (Stupid idea) It has all the worst traits of both standard multi-focal and progressive addition "invisible" bifocals.....  put a progersssive lens in a flat top design????

This may sound stupid, but can some explain to me why no one has come up with a "blended executive trifocal"???  Is this not we we all want the perfect progressive to be?   

1. unlimited width at all distances with no perephrial distortion
2. easy adaption with no "swim"
3. cosmetic acceptance with no "lines" or image jump.


I guess I just dont get the physics, otherwise I'd be a rich man..

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## sandeepgoodbole

[This may sound stupid, but can some explain to me why no one has come up with a "blended executive trifocal"???  Is this not we we all want the perfect progressive to be?   

1. unlimited width at all distances with no perephrial distortion
2. easy adaption with no "swim"
3. cosmetic acceptance with no "lines" or image jump.

That's Excatly what I wanted to say.. you have refined what I am calling Exceutive Pals last couple of days ..That would be great!:cheers:

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## Steve Machol

I hate to burst everyone's bubble but there is no way to create a progessive surface without some distortion.  If you think this is easy to do, then try it yourself with some model clay.  Cover the surface of a Flat-Top or Exceutive bi/trifocal lens with clay.  Then carefully remove the clay retaining as much of the original surface topography as you can.  Now use your fingers to smooth out the lines without reducing the reading area or introducing other distortions.

If you can do this, then immediately locate a patent attorney.  You are destined to be very rich indeed! ;)

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## shanbaum

> *Steve Machol said:* 
> If you can do this, then immediately locate a patent attorney.


Or an exorcist.

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## Refractingoptician.com

::

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## Refractingoptician.com

""

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## John R

> *Gary said:* 
> Randomly aimed it at whatever. The result ? A beautifully focused , full field picture of whatever it was aimed at. 
> 
> Now that is a real progressive lens !!


Mmm, but a bit bulky to have in a pair of glasses....:hammer: 
You can have this now...You just need a pair of s/v specs for every distance..

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## Refractingoptician.com

::

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## paw

I think lens designers? manufacturers?  marketers? need to consider that state of the art can't get TOO expensive for the average Joe Eyeglasses.  We are told by marketing materials to encourage second pairs and prescription sunglasses.  How many people are going to spend this kind of money before they figure out that one zap of LASIK is more cost efficient in the long run?

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## John R

> *paw said:* 
> I think lens designers? manufacturers?  marketers? need to consider that state of the art can't get TOO expensive for the average Joe Eyeglasses.  We are told by marketing materials to encourage second pairs and prescription sunglasses.  How many people are going to spend this kind of money before they figure out that one zap of LASIK is more cost efficient in the long run?


I think LASIK has a long way both in terms of time and cost before it becomes more cost effective. Dont forget even after LASIK folks will still need glasses. Sure not as bad powers but glasses all the same. Untill someone comes up with replacement lenses that can replace your damaged ones in your eyes then glasses are here to stay.

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## John R

> *Gary said:* 
> Actually, the camera's auto focusing mechanism has already been adapted to help low visual acuity people get back into the school classroom. The idea is not far fetched. 
> 
> Eye position sensors are a reality . Auto focusing sensors are a reality. Adjustable , controllable lens systems are a reality. The two together with computer chip technology may well be  tomorrows answer to full field sight .


Yes these things may be around now, but like many other so called inovations that make the headlines. How long if ever will they find their way to the general public's market place.
Sure stuff like auto focusing on camera's works but look how bulky it is even on the smallest camera's compared to a pair of frames which it will have to be fitted into...Moden frames are getting smaller in all ways,  which leaves less room for this type of technology.

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## Di822

Well, all I can tell you is from my own personal experience.  Fifteen years ago, I went into my first progressive.  It was something from Pearle.  Seems like it was a Sola XL.  Not sure.
In 1991, I began selling the Comfort by Varilux.  For the first time, I could read easily without having to work at it.  The periphery was "ok".  I could tolerate it.  Then I went to the Panamic when it came out a few years ago.  The periphery was much better.  Not a lot of change otherwise.  This year I am promoting the Hoya Wide and Hoya Summit.  This was the most remarkable change I have ever experienced.  The optics in the Phoenix Hoya are awesome.  It has the clarity of looking through glass to me.  I haven't seen things so sharp in 15 years.  I presume it is because of the higher ABBE value.  I have not had one non-adapt in 6 mos. of selling it.  And I have switched all my Varilux people to it without a single complaint.  Matter of fact, I see them experiencing what I saw the moment I put their glasses on them.  It is almost like having AR on your lenses.  Very clear.
Does anyone have experience with this lens and know more about it than me?  
I AM THE " X VARILUX QUEEN"

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## Optical Plumber

> *paw said:* 
> How many people are going to spend this kind of money before they figure out that one zap of LASIK is more cost efficient in the long run? ...


There will always be a significant percentage of the population who for one reason or another (dangers both real and imagined) will never permit the wielding of sharp objects in the vicinity of their eyeballs.

Terry

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## Optical Plumber

Adaptive optics could potentially provide an incremental improvement over the best of today's PAL designs. This technology has already been hinted at by several of the posts in this thread. Here is an excerpt from Adaptive Optics Discussion 




> Some of the technology derived from adaptive optics (AO) research is already being used by ophthalmologists to measure aberrations in the eye with unprecedented accuracy, and it may not be long before AO-based devices replace the conventional phoropter used to calculate prescriptions for eyeglasses and contact lenses. In addition, researchers are using adaptive optics technology to obtain extraordinary views of microscopic structures in the eyes of human subjects


Taking this idea one step further, one could use the data from the Adaptive Optics phoropter to generate a customized surface on the lens. This technology, however amazing it may seem, will STILL suffer from the frequently mentioned flaw of peripheral distortion in PAL designs. 

It seems to me that the idea of a true variable focus lens such as is found in cameras, combined with adaptive optics technology will be the ultimate future of NON-intrusive vision correction. In my wildest imagination, I see a flexible lens, with the shape controlled in much the same way as the human eye's lens is controlled.

On the otherhand CCD and nano-chip technology should eventually provide the ability for everyone who is willing to undergo the necessary cerebral implant, to see everything (infrared, ultraviolet, night vision, etc.) with 20/10 vision.

After this, Xray vision should be a cake-walk!

Terry
:D

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## ogEE

a new pal design is available in germany from ZEISS.  this lens is "built" on an individual basis using 9 perameters.  to do this you need a $30K piece of equiptment called a video infral system. this lens will not be available to the USA market untill about 2004. check it out at www.zeiss.de.  i think you will see lenses in the future that will move beyond the constrictions of physics.  how about an LCD lens that changes foci as the cysiline lens changes it's shape??? the computer is a box;  the MIND is infinate.  thats my perspective.  and yours?
                         yours in optical fun,
                           ogEE (aka  phil harris )

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## dfisher

Custom progressives are the upcoming "next generation" of lenses.  Some are "custom molded", a technology I don't at all understand, but two German companies are doing true custom front surface design based on PD, vertex, Rx, add, frame dimensions and who knows what else.

How about**:
     * The optimum base curve for *every* Rx?
     * Corridor length based on the "B" measurement
     * Change the with of either the intermediate or near
        ( based on occupation or lifestyle.)

These are just a few of the things that can be customized for each Rx.  And as R&D continues, the software can be refined to create the next "next generation" lens.

Zeiss Individual is coming very soon.  And in Europe, the Rodenstock Individuality and Impression ILT are available using this very technology.  From now on new designs will simply be software updates.

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## Nikki B

see www.discoverylens.com for details :D

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## dave lien

Steve,

Would there not be some optical beneifit if the design on a progressive could be atoric?  With a more indepth rx range then what is  now in single vision    My thinking here is that there would be less distoration.  Thus an improvement on lens design.

Dave

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## Steve Machol

> *dave lien said:* 
> Steve,
> 
> Would there not be some optical beneifit if the design on a progressive could be atoric?  With a more indepth rx range then what is  now in single vision    My thinking here is that there would be less distoration.  Thus an improvement on lens design.
> 
> Dave


Yes, an atoric design would be an improvement, particularly for larger cylinder powers.  In fact the only way to do this effectively is with backside atorics that are custom-ground per prescription.

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## Robert Martellaro

How about a variable index of refraction lens?

http://www.eggfactory.com/egg_na_062801.html

The refractionist hands you a Rx in the form of a smartmedia card. The optician downloads to your eyeglasses along with any firmware upgrades. Looks like I better take that unix class I've been putting off!

http://www.darpa.mil/dso/thrust/sp/bio_optic.htm

Instead of cleaning your glasses twice a day you will need to feed them twice a day.

Robert

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## OpticianLynn2000

:Mad:  You know, I've been wearing progressives for about 13 years now, and have worn MANY of the different brands.

There only have been a couple that I feel are not too bad.
No matter who makes the lens, the peripheral still sucks with a progressive.

The stonger a "seasoned wearer's" RX gets, the more they will notice the characteristics of a progressive.  Someone comes in to get new glasses, wears a Varilux, same lenses for say.....about 5 years.  Now the RX changes big time.  Guess what!  They must be told that they will have to find their new areas and will be more aware of the characteristics at first.

I still wear separate computer glasses at home.  The progressive is great, however, us presbyopes need more than one pair to accomodate ALL of our needs.  

What I tell patients is this.........There comes a time when one pair will not work anymore.  There comes a time when we must "Rob Peter to Pay Paul", or give something to get something.  When I explain that to them, they are ready to try the lens and are not expecting to see through them like their old single vision glasses!:)

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## Jenean Carlton

Since we know that progressive designs are limited by the laws of physics it is quite possible that, with the current materials and productions methods, PAL designs have reached their limit. Furthermore, there are so many older designs available in the market, rather than being withdrawn by the manufacturer when newer designs become available, which confuses the selection process.

One way to determine the proficiency of a PAL design is to know the year that the lens entered the marketplace. This way, the technology that was available at the time of release is an indicator of how well the lens will perform. For example, PAL's developed in the past 5 years, versus designs created 15 years ago, will perform much better due to computer aided design technology (CAD). CAD assists the lens designer in maximizing optical zones and in creating superior lenses to those that were developed before this technology was perfected.


Congratulations to all of those responsible for producing this forum. It is very well done.


Also, Steve, after much pondering  I believe that the "Hokey Pokey" IS what it is all about.

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## Steve Machol

> *Jenean Carlton said:* 
> Congratulations to all of those responsible for producing this forum. It is very well done.


Thanks Jenean!




> Also, Steve, after much pondering  I believe that the "Hokey Pokey" IS what it is all about.


I knew it! :D

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## ogEE

Please,  please,  please,  stop calling them "blended or no-line trifocals !  Tell it like it is:  INFINATE VISION. Thank you in advance for your cooperation.
                    Yours in optical fun,
                         ogEE (aka Phil Harris )

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## Optical Plumber

I am following this thread with great interest because I deal with progressives regularly as part of my job and also because I wear them. After many years in the software business dealing extensively with progressive lenses, I still don't feel that I understand the product very well. I have worn four different progressive designs from two different manufacturers over the past few years and none of them has been completely satisfactory. I am a -.75 with a +1.75 add. My problem is that I don't believe I am achieving optimum visual acuity in either the distance or the near. Also, there are still many functions in the intermediate zone that I don't use my glasses for.

My question is this. Should I expect to get the same level of visual acuity in my progressives that I get in my single vision drivers or my single vision reading glasses? 

Terry
:(

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## Jim Stone

> *Carol D said:* 
> I would like an "occupational progressive" similar in function to the double segs we use for mechanics and electricians. I want a LARGE central distance target with a mid-range and near beneath and a large intermediate above. Something useful for pilots, mechanics, people running large commercial printing presses, etc..
> Not like the old AO technica or the Overview.  Anybody got something in the works?
> 
> Carol D



There was a occupational progressive made, but the manufacturer deemed the market not large enought to continue the product. No more overvue. I suggested it many times.  Just like the super modular.  Not a big enough market.

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## jherman

There is still room for improvement and with the better software and not being limited to one side production, a better lens is now becoming available.

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## QDO1

> Sola came out (very boldly) with the "Smart Seg" (Stupid idea) It has all the worst traits of both standard multi-focal and progressive addition "invisible" bifocals..... put a progersssive lens in a flat top design????
> 
> This may sound stupid, but can some explain to me why no one has come up with a "blended executive trifocal"??? Is this not we we all want the perfect progressive to be? 
> 
> 1. unlimited width at all distances with no perephrial distortion
> 2. easy adaption with no "swim"
> 3. cosmetic acceptance with no "lines" or image jump.
> 
> 
> I guess I just dont get the physics, otherwise I'd be a rich man..


There once was, a few years ago, a blended round 24 seg, and it was awful, and patients complained like hell about it.  basically there was a 4 (ish) mm blend zone to the edge of the seg.   the biggest problem was the huge "wobble" experienced in geting past the blended bit.  Looked OK, but in practice - complete failure

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## QDO1

I saw a paper once about a LCD type arragment, which worked like a fresnel type system, but the divisions on a much much smaller scale.  As current was passed into this lcd plate, the plate became more positive or in power, enabling a crude focusing mechanisim to be made.  This would be a really great advance.


Did anyone ever see the sunglasses that incorporated a LCD system that darkened as current was applied to it?  Hit a trade show here in the UK as a prototype about 6 years ago, and never saw them since.  you just pressed a little button on the temple and they darkened immediatally

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## slaboff

> A standard progressive with the intermediate and near widths of one of the office lenses wouldn't be a bad creature. I am not sure if that wouldn't cause too much distortion in the distance though.


 
I think this is a great idea, maybe a reverse completely clear bottom with a small corridor for the distance vision... similair to the shamir office but not so high up...

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## spartus

> Originally Posted by myodisk
> _This may sound stupid, but can some explain to me why no one has come up with a "blended executive trifocal"??? Is this not we we all want the perfect progressive to be?_


Oddly enough, this has come up before.  :)

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## Chris Ryser

> *But the nature of the beast is that when you make one of the zones wider, you have to give up something elsewhere*.


This just said it all. There is no more mountans to climb. The top has been reached a while ago. 

We better start learning to sell progressives they way they are, to the paptients that need this type of lenses and not sell them to the ones that are better off with an other type of lens.

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## Bill West

I just got my Definity lenses.
Amost like wearing a single vision rx. +2.50 ADD
NO KIDDING
THIS IS THE REAL THING
if it gets any better than this I want it.

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## lensgrinder

What if there is more to accomplish?  About a year ago I talked to the people at Schneider about there free form techology.  From my understanding you can grind a progressive front on any SV lens.  With this in mind think about a day when we would be able to grind the back of the lens to match the front of the lens, meaning we would not grind a lens with just one or two curves on the back.  Maybe this is being done or will eventually be done.

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## Jedi

> I just got my Definity lenses.
> Amost like wearing a single vision rx. +2.50 ADD
> NO KIDDING
> THIS IS THE REAL THING
> if it gets any better than this I want it.


So what happened to your opinion from this 
thread?

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## HarryChiling

Just a thought but what if the proggressive lens was made of varrying index materials in such a way that the difference in the index of the material could eliminate more of the residual astigmatism.  JUST A THOUGHT.  I have seen on this board how one company claims that this is what they use to create a custom wave front SV lens.  If this technology was cmbined with proggressives it would be interesting at the least.

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## Darryl Meister

What you're describing is known as _Gradient Index_ technology (or "GRIN"). There has actually been some research into the application of this technology for progressive lenses, but it's still in its infancy.

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## HarryChiling

Do you know where I can find more info on "GRIN"?

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## drk

Man, this thread is an oldie!

I think with customized progressives, while we may not be able to make vast improvements _on every particular lens,_ we will be able to make a large improvement on the progressive lenses being worn in the world _as a group._

As an analogy, when silicone hydrogel contact lenses came out, some cases had immediate, dramatic benefits, but really most cases were small improvements.  Over time, though, the "wearability rate" of SCLs have gone up (say, from 75% to 88%, e.g.).

With freeform progressives, we ought to be able to make most wearers a little happer, some wearers much happier, and some wearers will stay the same, but all-in-all, the entire group of wearers will be noticeably better off.

The idea is not of revolutionary design change, but that of optimization of the existing design.

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## Darryl Meister

> Do you know where I can find more info on "GRIN"?


Your best bet would probably be to do an Internet search for "Gradient Refractive Index" or "GRIN." I'm sure it will turn up several interesting sites. Here is an article (from a PhD thesis) that I ran across a few years ago on one approach to gradient index progressive lens optics: Gradient Index Progressive Thesis.

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## QDO1

GRIN - sounds like a lot of hard work... multiple indicies on the same lens to combat distortion.  Better to look at regular use of Atoric/aspheric surfaces on conventional index lenses.. at least most surfacers will have the machinery to make the lenses (eventually)

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## chip anderson

Since most contact lenses are made from extruded rod as opposed to compressed sheet, we have been seeing lenses with variable indexes ever since.

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## QDO1

> Since most contact lenses are made from extruded rod as opposed to compressed sheet, we have been seeing lenses with variable indexes ever since.


yea right, and the manufacturers work special curves in to compensate for distortions and all that.. I bet not

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## Bobie

Free Form + both side aspheric + Dual Progressive Surface + Individual + Eye/Head movement + Plastic index 1.8 , ABBE 40 , very strong for rimless frame = PALs for future = Retail price at 5,000 US$ net.
I believe that , we have more than 50,000 rich people around the world who would like to buy it more than 1 pair for 1 person.

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