Progressive Lens Design: Where do we go from here?

[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.

[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

[OpticianLynn2000]

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!:)

[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 Furthermore, there are so many older designs available in the market, rather than being withdrawn by the manufacturer when newer designs become available, which confuses the selection process.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.

[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

[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 )

[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
:(

[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.

[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.

[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

[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

[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...

[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. :)

[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.

[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.

[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.

[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?

[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.

[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.

[HarryChiling]

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

[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.

[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.

[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)

[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.

[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