More *Free-Form* Confusion!

[Barry Santini]

My brain desires a lens that feels comfortable, and provides the quantity of vision at the far and near point that comes closest to what the most refined refraction can provide. OTOH, this is a blend of vision and optical science- where one might say that "one eye sees, the other feels".

Ah yes, Robert. You've stated what I preach: There's a brain behind every evaluation. And every evaluation is a comparative against previous visual experience. Although we know what the numbers mean and can forecast optically, what we cannot know is just how an individual will react to a given lens design/Rx. So, statistically, we look at the overall satisfaction and feedback from our clients.

This, then, is the main reason I will continue to vet out the best lens technology I can find, and recommend it to my clients. I am committed to this, and they expect no less (just like others here).

People like "us" are the only future of eyewear/opticianry. The basement is already targeted to be eliminated by refractive technology.

IMHO & FWIW

Barry

[SailorEd]

Just say it like this: "Our best no-line multifocal design is $xxx, which comes complete with the super-slick, easy to clean anti-reflection treatment".

I go a step further and show them a simple diagram on how free form lenses help alleviate coma aberration. People "get" "less blurriness" and they jump at it. We make follow up calls to all our patients who get glasses and to a person, each one who has purchased our free form lens is very satisfied (some even say they "love it"). Pretty good indication they are coming back and will stay with the free form design. AND, a good indication that if they go somewhere else and get a "less expensive" (read: inferior) lens, they won't be happy with it and will ultimately return to us.

The only lenses we offer here is the Varilux Ellipse and Physio both regular and 360 and the only AR we offer with these is the Avance'. Excellent results with both.

[chip anderson]

SailorEd:

You do realize that you are admitting to selling lenses with "blurriness." The ultimate way to eliminate this "blurriness" would be a translating bifocal or trifocal. Why not carry it all the way and convert these people to translating bifocals?
By your statement here, it's what they would be happiest with.
Your statement seems to say: Our lenses have abberation but less of it.

Chip

[SailorEd]

SailorEd:

You do realize that you are admitting to selling lenses with "blurriness."
By your statement here, it's what they would be happiest with.
Your statement seems to say: Our lenses have abberation but less of it.

Chip

Yes, I do realize that I am selling lenses with blurriness in them. First time wearers need to be told this ... and those who already wear progressives, they already know it. My main "thrust" is to educate the patient - to tell them the good and the not so good about the lens I am recommending to them. I show them a simple diagram of how a progressive is designed and explain to them that there is going to be some blurriness if one moves their eyes to the edge of the lens and I explain the benefits and limitations of a progressive before they buy it.

Now, to tell them that a new lens on the market (Physio 360 or the like) has less blurriness and then to show them in a simple diagram why (coma aberration) ... well, they "get" it and I am finding about 75% of the time decide to go with it. I had a lawyer come in and I do something that I very rarely do ... I actually "hard sold" him on the 360. He came back with his wife to pick up his glasses and sat down and said, "Ok, so you have glasses that will allow me to see through walls, huh?" I smiled and then put them on and adjusted them. He was absolutely impressed ... the clarity was excellent and he was still talking to his wife about them as he went out the door. I made him promise he'd tell everyone at the law firm about them. (smile).

So, yeh, I'm "right up front" with our patients ... and they appreciate it. And so, with this economy ... I'm saying "What recession?" Our sales remain strong and our patient base keeps expanding.

[HarryChiling]

Yes, I do realize that I am selling lenses with blurriness in them. First time wearers need to be told this ... and those who already wear progressives, they already know it. My main "thrust" is to educate the patient - to tell them the good and the not so good about the lens I am recommending to them. I show them a simple diagram of how a progressive is designed and explain to them that there is going to be some blurriness if one moves their eyes to the edge of the lens and I explain the benefits and limitations of a progressive before they buy it.

Now, to tell them that a new lens on the market (Physio 360 or the like) has less blurriness and then to show them in a simple diagram why (coma aberration) ... well, they "get" it and I am finding about 75% of the time decide to go with it. I had a lawyer come in and I do something that I very rarely do ... I actually "hard sold" him on the 360. He came back with his wife to pick up his glasses and sat down and said, "Ok, so you have glasses that will allow me to see through walls, huh?" I smiled and then put them on and adjusted them. He was absolutely impressed ... the clarity was excellent and he was still talking to his wife about them as he went out the door. I made him promise he'd tell everyone at the law firm about them. (smile).

So, yeh, I'm "right up front" with our patients ... and they appreciate it. And so, with this economy ... I'm saying "What recession?" Our sales remain strong and our patient base keeps expanding.

Please stop saying coma aberration.

[Uncle Fester]

Please stop saying coma aberration.

I'll bite--My newest favorite optical lingo to throw at the engineer or anyone else who I want to distract from looking at the man behind the curtain;) is to refer to Seidel Aberrations. One of which is "coma". So is this incorrect because coma is an aberration? Would it be correct to say "the aberration coma"?

[HarryChiling]

I'll bite--My newest favorite optical lingo to throw at the engineer or anyone else who I want to distract from looking at the man behind the curtain;) is to refer to Seidel Aberrations. One of which is "coma". So is this incorrect because coma is an aberration? Would it be correct to say "the aberration coma"?

Because spherical aberration and coma are both aberrations that would be problematic in wide aperature systems, the eye has a pupil that limits the area of the lens that is used so these are the least problemtic aberrations to worry about from a spectacle desingers point of view. It sounds great to talk about sphercal aberration and coma, but they don't mean anything in spectacle lens design if you had to sacrifice somewhere I would rather a lens with more coma and sph aberration than oblque astigmatism, distortion (in it's true sense), curvature of field, or even chromatic aberration probably in that order as well.

You want to reduce coma in the corridor order a Natural long corridor means less disfference in power from the top of aperature to the bottom of the aperature. You want to redue coma hav the patient instill miotics or go out in full on sun without any filters to their lenses. If a lens is sold to you because it reduces coma then you've been had IMO.

[Uncle Fester]

Because spherical aberration and coma are both aberrations that would be problematic in wide aperature systems, the eye has a pupil that limits the area of the lens that is used so these are the least problemtic aberrations to worry about from a spectacle desingers point of view. It sounds great to talk about sphercal aberration and coma, but they don't mean anything in spectacle lens design if you had to sacrifice somewhere I would rather a lens with more coma and sph aberration than oblque astigmatism, distortion (in it's true sense), curvature of field, or even chromatic aberration probably in that order as well.

You want to reduce coma in the corridor order a Natural long corridor means less disfference in power from the top of aperature to the bottom of the aperature. You want to redue coma hav the patient instill miotics or go out in full on sun without any filters to their lenses. If a lens is sold to you because it reduces coma then you've been had IMO.

[Genuflecting Optician]:cheers:

[chip anderson]

One must remember that although the pupil may be from one to 8 mmm the patient is seeing through (siimultainiously) much more of the lens, even in a contact lens the amount of lens being used is larger than the pupil (let's leave out selective brain interaction with multifocals here).

If this were not true what one view at far distances would be no larger than pupil diameter.

Chip

[DragonLensmanWV]

[Genuflecting Optician]:cheers:

This works:

[HarryChiling]

One must remember that although the pupil may be from one to 8 mmm the patient is seeing through (siimultainiously) much more of the lens, even in a contact lens the amount of lens being used is larger than the pupil (let's leave out selective brain interaction with multifocals here).

If this were not true what one view at far distances would be no larger than pupil diameter.

Chip

Your right, but sph abb and coma are dependent on the pupil size. Also although you may view an entire room only the macula is capable of BCVA while the remainder of the room will fall on other parts of the eye, that means if you were to use eccentric viewing techniques depending on how eccentric your view the VA is gauranteed to be less than 20/20.

Basically to bring something into focus you must look directly at it.

[Comma]

To all spherical aberration and coma lovers :
Do this little exercice just for fun :
Stare any letter on the 20/20 line, then, still staring at this letter, try to read any letters that are more then 4 inches away on the same line, BUT KEEP staring at your first letter. You won't be able to read them at all.
Want to go further ? Place something around 3mm over your glasses to cover that same letter and try to read the other letters. You won't be able.

My conclusion : we really read and have real crisp vision in about a 3mm diameter at any time in any lens. 1.5 mm (side to side, up and down) from that exact point of the lens we are looking at. Spherical aberrations at 1.5 mm ? You have to have a quite strong RX ! Mr Prentice is my friend...

You won't even notice these aberrations in real life because our vision is far from being perfect surrounding that little 3mm area of our lenses.
I did the same with CL : a 1mm round object places directly on the lens did about the same thing. 0.5 mm causing spherical aberrations ?

I think spherical aberrations and coma are mostly pointless in real life

Now, do your own conclusions...
Or maybe I'm wrong ?

Please forgive my quite unperfect English writing :o

[stellarindia01]

I just find it amazing that something as simple as consistent minimum seg heights can not be found! How are we supposed to believe that the actual lens designs will be consistent?
Lisa11

[SailorEd]

Please stop saying coma aberration.

Well, you see, I can't stop saying it because the significant reduction in coma aberration is one of the major advances in free from technology. Yeah, some other aberrations in lens design would be nice, but, since we're talking about existing free-form technology and since I was talking specifically about Varilux Physio 360, then I have to talk about just what that lens does for my patients. i. e.

"• Varilux Physio. Even the best progressive eyeglass lenses distort light waves as they pass through the peripheral optics of these lenses, reducing visual quality. The Varilux Physio and Physio 360 are progressive designs that minimize many of these distortions in the lens, particularly coma, by applying a technology known as Wavefront Advanced Vision Enhancement (WAVE) to identify and compensate for aberration deformities by controlling the quality of the wavefront that passes through the eyeglass lens. The result, according to Essilor, is a progressive lens with enhanced central and peripheral vision, a 30% wider corridor, greater coma control, and more contrast and greater acuity in all fields of vision"

And, well, what does this mean to my patients?

• As much as 30 percent increase in contrast sensitivity resulting in a more accurate duplication of the visual performance achieved during the eye exam (much smaller lenses used in that room, hence, less coma aberration).
• The benefit of First Time Ever control of the Coma aberration , allowing for sharper distance and improved night vision that is Superior to all other lenses.
• An optimized edge-to-edge performance that goes beyond the perepheral limits of traditional lenses.

Now, granted, these are "selling points" but the patient understands them when I explain them in the context of "coma aberration" and when I explain just what we mean by that in a simplified diagram.

[optical24/7]

Physio's and the Ellipse ( even the 360's ) are not Free Form lenses. The regular versions are traditional Semi-finish, surfaced on the back conventionally.

360's are the same exact lenses, only digitally surfaced on the back side.

The closest lens Varilux has to free form is their Ipsio, and it's not totally free form. It's got a pre-cast progressive front surface.

[SailorEd]

Physio's and the Ellipse ( even the 360's ) are not Free Form lenses. The regular versions are traditional Semi-finish, surfaced on the back conventionally.

360's are the same exact lenses, only digitally surfaced on the back side.

The closest lens Varilux has to free form is their Ipsio, and it's not totally free form. It's got a pre-cast progressive front surface.

There can be a million and a half definitions of what makes or what does not make a free form lens. Actually there are no free form lenses, there are only lenses that are manufactured using free form technology.

In the case of the Physio and Ellipse regular and "360", while the regular Physio and Ellipse are spherical in design on the front surface and then surfaced regularly on the back, the Physio 360 and Ellipse 360 are Digitally molded on the front surface and digitally surfaced on the back.
http://thelensguru.com/digitalChart.php

Hey, bottom line ... they are a much better lens and I have had a very good reaction from my patients ... that being said ... whether they meet the "true" nature of free form or not, i.e. extra measurements involving eye and head movements and a lot of extra equipment ... I'll stick with them for now because of their superior performance.

[HarryChiling]

The result, according to Essilor, is a progressive lens with enhanced central and peripheral vision, a 30% wider corridor, greater coma control, and more contrast and greater acuity in all fields of vision"

Thank you, I have seen the light. Remember this thread is about confusion with FF progressives and i believe that companies are dropping the ball by not educateing the psuedo professionals that are selling their products. With that said the lens may still be a good lens, but coma is not a significant aberration so I wouldn't choose a design based on reduction of coma alone.

[HarryChiling]

In the case of the Physio and Ellipse regular and "360", while the regular Physio and Ellipse are spherical in design on the front surface and then surfaced regularly on the back, the Physio 360 and Ellipse 360 are Digitally molded on the front surface and digitally surfaced on the back.
http://thelensguru.com/digitalChart.php

Most manufacturers are starting to digitally mold their lenses nowadays so the traditionel ellipse and the traditional physio are digitally molded either way the 360 just refers to the technology used on the back surface.

[optical24/7]

Most manufacturers are starting to digitally mold their lenses nowadays so the traditionel ellipse and the traditional physio are digitally molded either way the 360 just refers to the technology used on the back surface.

Exactly. There are absolutely no differences on the front surface of traditional Physio and Ellipes compared to the 360 series. That's also why there are no difference in the laser ingraving between the 2 . (regular and 360 series.)

[HarryChiling]

You know these kind of conversations will continue to go on untill their are some sort of metrics set in place. The accepted norm for corridor width and marginal astigmatism is 1.00D or the sph equiv of 0.50D, if a company were to say our corridor is 13mm wide in the intermediate, then this would provide a great deal of information for the fitter. The threshold for TCA is 0.1. The problem with the metrics is gonna be the die hard fitters of a certain design that right now focus on the wider corridor are going to see that their are sacrifices in other areas of the desing which is acceptable, but it would allow fitters to better fit their patients need with the correct design. Not that's a customized fitting and it can be done with even traditional desings.

FF is a great technology and has it's rightfull place at the top of the food chain in PALs but given how little we know and I mean we as me and everyone else included it leaves much to be desired.

[Barry Santini]

By the way (and Harry-Darryl, correct me if I'm wrong here):

Spherical aberration is an *on-axis* aberration

Conceptually, Coma is spherical aberration's *off-axis* first cousin.

Barry

[HarryChiling]

By the way (and Harry-Darryl, correct me if I'm wrong here):

Spherical aberration is an *on-axis* aberration

Conceptually, Coma is spherical aberration's *off-axis* first cousin.

Barry

That's a good definition.

[chip anderson]

At first this may seem like a duplicate post but..
Could not "free-form" be used for these specialty needs? It seems this would be thier greatest potential
If a patient comes in with a "standard Rx" and desires:
a: Glasses to focus shorter to say, fix watches.
b: Glasses to view a particular work station at an unusual close distance such as an overhead display or something at 8' and 6'6" high.
c: An artist that wants to view an easel with offset prism/add but be out of the way for distance in the opposite direction.
d: A painter or mechanic that needs to see overhead at a distance different from his near/distance range.
e: Piano organ player with special distance/ intermediate/ near ranges to see the music, keyboard/ director.

Are these technically within the possiblities for current "free form" technology?

Chip( Neo-optician)

[Jacqui]

All should be possible with current technology.

[Lazarus]

Awtech,

So.......is it safe to say that a Seiko Supercede(or Autograph II, or Indo, etc) lens may end up being a different design from lab#1, then it is from lab#2, and both different from lab#3?

If so............................should we all sill drink the Kool-Aid and assume that these lenses are all the same?

For those that my bring up the traditional surfacing statement and how it isn't any different scenario, I will assume that a 6BC Sola XL is the same *design* no matter what lab surfaces it. A Hoya Wide starts out the same design regardless of where it is surfaced, or is it different?

Fezz,
You raise great questions. I'll blow your mind even further. I ordered three digital progs(i probably shouldnt mention which brand) from three different labs. They are considered the top digital prog labs. 2 on east coast and one in mid-west. I ordered the exact same rx, same lens , same measurements and provided same exact frame tracing. They send you a sheet with the verified rx that we should check. They should be the same right?????? Well they werent. All 3 labs provided different verified specs. Why? How do I know which of the 3 are the best for the patient? Is there no standard? Conduct that test yourself and see what you get. All three labs are provided with special software from the same manufacturer. But they also have there own lab software system which i guess works with the lens manufacturer software. My guess is when you mix the lab software with the lens company software its causing a different result?? So now the question becomes which is right? They all cant be right or can they? Are we to accept blindly what is on the piece of paper? Would love to hear feedback