RXs that benefit most from FFSV?

[joptid]

Hi, I've introduced myself a couple of times but if you haven't seen I'm new here and pretty new to the profession. We have a semi-retired optician who comes in a couple of days a week to augment his SS and retirement benefits, and while he is an absolute WEALTH of information and experience, sometimes it seems like he checked out of staying current a while back. Our other optician doubles as office manager and while he's more experienced than me, a lot of times he's got his head too buried in the paperwork to help much. So I find myself on the front lines a little more than I probably should be at this point.

My question, about which my ignorance was exposed a couple of posts ago is when is the upgrade to FF of significant benefit in a single vision rx? I've had some experiences where maybe the patient was just saying they were happy because I'd hyped it, and I'd rather be on a sound basis for recommending it. Of course, I get pushed to push it and I'd rather not when it's not going to be of a significant benefit and I'd like to be able to push back armed with some of your experiences.

Again, my thanks to all of you, reading postings here has been an invaluable benefit not only to me, but the people I serve.

[Barry Santini]

Any cyl over 1.25
Good acuity and contrast sensitivity
pupil heights more than 6mm above MC
wrap angle > 8

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[huskypaul]

In all honesty I can not see any reason as to why you would not want to put your patient into a FFSV lens design. We use them for all of our CR 39 lenses. If you are trying to pull away from the rest of the herd and differentiate your services from another, provide your patients with the best vision possible. If your patients prefer HD TV from analog they will certainly be able to see the difference in the FFSV. It is not hype, you are doing a service to your patients by providing them with the best window to look thru. Make a pair up for your self if you haven't yet done so. I am a -5.25 PAL wearer but I've made a pair of FFSV CR 39 distance and a stock SV CR 39 distance, I can certainly see the difference in performance between the two lenses.

[EyeCare Rich]

I like Barry's answer, but I go just a bit further. I start at 0.75 cyl, I also take certain lifestyles into account, such as an engineer who is very picky about everything. on the Sph side, anything above 1.25 + or -.

I also want to add Welcome to Optiboard. Great question, ignorance does not stick around when good questions are asked.

[LENNY]

So according to your suggestion stock houses will be gone in a few years from now!?!?!?
Or FFSV wil (can IT?) become stock?

[Slim]

I dont think I am a great canidate. went from cheap cr-39 warehouse stock lenses to a iScript FF SV and I see nothing to talk about IMO an Im SUUUUPER picky.

-1.25 -1.00
-1.75 -1.25

[DanLiv]

I dont think I am a great canidate. went from cheap cr-39 warehouse stock lenses to a iScript FF SV and I see nothing to talk about IMO an Im SUUUUPER picky.

-1.25 -1.00
-1.75 -1.25

Me too Slim, my Rx is almost the same and I perceive no difference between (good) finished stock lenses and FFSV, and I've worn half a dozen FFSV and several dozen conventional and finished in every material. In the early FFSV days I really expected to get the "wow" the reps were hyping, as I ostensibly have enough cyl and my BCVA is 20/15, so I thought if the difference is perceptible I would see it. I don't, but I think it's personal visual processing that makes me miss the benefits. I have lower Rx customers who swear to the improvement, and I didn't even hype it hard.

The ranges suggested here as great guidelines. Also joptid read Darryl Meister's article Principles of Atoric Lens Design for excellent understanding of exactly what FF is doing.
http://www.optiboard.com/forums/show...Darryl-Meister

[Java99]

What Barry said, plus: CL only wearers moving into glasses, and anyone who talks about fishbowl effects.

[fjpod]

So according to your suggestion stock houses will be gone in a few years from now!?!?!?
Or FFSV wil (can IT?) become stock?

I don't see it happening.

I don't understand how FF is better when the eye keeps moving to a different point on the lens.

[Barry Santini]

I don't see it happening.

I don't understand how FF is better when the eye keeps moving to a different point on the lens.

Interesting, since this is PRECISELY the point of FF SV

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[Robert Martellaro]

...when is the upgrade to FF of significant benefit in a single vision rx?

At or above about 3 D in the strongest meridian, lowering to about 2 D when compared to semi-finished front aspheric designs. SV lenses have fairly close base curve spacing (usually 1 D), minimizing oblique astigmatism and mean power error, especially with lower powers and simple surface designs.

That's assuming that the software is capable of correcting these aberrations and errors over a wide range of Rxs, lens materials, and lens positions (tilt/vertex distance)!

[fjpod]

Interesting, since this is PRECISELY the point of FF SV

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yes...if the eye stood still and was always looking through the true optical center.

[Robert Martellaro]

For now, this discussion concerns low-order aberrations only.

[sharpstick777]

We actually did testing with premium stock lenses from Seiko, compared to 5 different SV FF brands. I am sure other premium Aspherics will perform well esp from Zeiss (I just didn't have them on the shelf) but 3 out of 4 people under a -1.00 cyl, under a -4.00 sphere said they saw better through the Seiko Aspheric stock, all in the same material and frames.

when Cyl or power exceeded those, it began to shift toward the favor of SVFF.

In all honesty I can not see any reason as to why you would not want to put your patient into a FFSV lens design. We use them for all of our CR 39 lenses. If you are trying to pull away from the rest of the herd and differentiate your services from another, provide your patients with the best vision possible. If your patients prefer HD TV from analog they will certainly be able to see the difference in the FFSV. It is not hype, you are doing a service to your patients by providing them with the best window to look thru. Make a pair up for your self if you haven't yet done so. I am a -5.25 PAL wearer but I've made a pair of FFSV CR 39 distance and a stock SV CR 39 distance, I can certainly see the difference in performance between the two lenses.

You're experience with your -5.25 would be consistent with all the information being presented here.

The reason I would personally stay away from FFSV where its not warranted, it that I would rather put the patient into a better AR or Transitions... assuming they haven't chosen those already.

[ThatOneGuy]

I didn't see a benefit to FFSV until I sat at my desk and realized I could my paper work very clearly even if I didn't point my nose. Unfortunately, I had to go to a standard aspheric due to BC control issues flexing my frame. I recommend FFSV for anyone who is going to wear glasses full time, or long term (work/driving). I do get a wow response from most people, but a few people wont see the big deal which is usually the result of not taking sufficient time to be certain they realize what they bought and why.

[Robert Martellaro]

We actually did testing with premium stock lenses from Seiko, compared to 5 different SV FF brands. I am sure other premium Aspherics will perform well esp from Zeiss (I just didn't have them on the shelf) but 3 out of 4 people under a -1.00 cyl, under a -4.00 sphere said they saw better through the Seiko Aspheric stock, all in the same material and frames.

when Cyl or power exceeded those, it began to shift toward the favor of SVFF.

Premium aspheric finished (cast) lenses are likely to have even closer base curve spacing, improving performance somewhat compared to semi-finished. Of course we won't use a finished lens for plus powers, so the advantage ends with minus only. But if the POW values are close to default, I'd expect the results that you saw with your wearing evaluations.

[jpways]

I considered anything over -2.00 cylinder only or over -6.00 total power (this would be sphere plus sphere values only I am not calculating for spherical equivalence) to be the points where I start talking about the "leading edge" of Single vision freeforms i.e. Zeiss' Individual SV, Hoya's ID SV, and Shamir's Autograph II SV. If I have a borderline prescription (within 20% of my limits) or those patient who I feel might benefit for the upgrade due to our discussions, I will start with mentioning what I consider the introductory designs, Hoya's IQ SV (a secondary atoric grind is added to the base aspheric progressive lens is how the IQ series has been explained to me by Hoya) as well as the lower level freeform designs: Zeiss' 3D SV and Shamir's Spectrum SV. At the labs I use the prices are fairly close to the SV aspheric design in their respective materials for the last 3 lens designs.

[Barry Santini]

FF without good abbe is badde.

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[joptid]

Thanks everyone for the replies. Thanks Eye Care Rich for the warm welcome too. Thanks DanLiv for the link to Darryl's article. Still working through it, good stuff.

Barry, I could be wrong, but from what I gather from your original post here, you don't see value in FF SV for simple SPH corrections? Also, about your last post, does that mean you wouldn't fit anyone in FF poly? I know, Trivex is the superior option, but just curious.
Huskypaul, so you recommend even low power corrections done in FF? I admit, I'm new to this, but it seems to me that it shouldn't make much of a difference for low powers when the cyl is low or not needed.

[Barry Santini]

Simple, low power spherical corrections only benefit, IMHO, from FF when the base curve required deviates by > 2D, flatter or steeper.

also, you can never forget the impact of low abbé, poly, or 1.67, on peripheral optics. It will all depend on eye point and lens size.

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[DanLiv]

Premium aspheric finished (cast) lenses are likely to have even closer base curve spacing, improving performance somewhat compared to semi-finished.

Simple, low power spherical corrections only benefit, IMHO, from FF when the base curve required deviates by > 2D, flatter or steeper.

Yup I routinely, and with great success, fit up to -5.00 and -1.50 cyl in premium finished lenses rather than FF. The FF gain is low, and the quality of premium finished is awesome. Flawless AR adhesion and performance and exceptional thickness control. Those aspherics are 1.1-1.2 CT every time. Even the most custom digital labs struggle to get within the expected ±0.3mm tolerance when I specify thickness.

FFSV isn't magic, it only better corrects for the errors of base curve deviation in conventional lens fabrication. When the base curve deviation is low (primarily with low to moderate cyl), there is nothing to improve upon. I've heard opticians discuss FF like it is magic (not here of course ;), claiming it improves vision in any Rx. Those are the same opticians that recommend plano AR lenses to reduce glare driving at night.

[sharpstick777]

Everyone experiences will vary because to my astonishment, many labs continue to GRIND every lens, even a -.50 SV! So you MUST find out if you lab uses finished aspherics, which brand they use, or if they grind. I personally recommend Seiko or Zeiss over Essilor finished. With Essilor lenses I get small deviations in base curves, probably from different manufacturing plants, and they run a little thicker.

Ground lenses (semi-finished blanks) will not be as optically pure as quality finished single vision because they usually only run on 5-6 base curves, where premium finished lenses have their own unique BC for every power. So if your patient or lab has or uses ground lenses, SV-FF will probably be a large improvement. If you or your lab uses quality finished lens, your experience will be different.

Note: "Finished lenses" are blanks that have the full rx power already cast into the lens, sphere and cyl. Semi-finished are the blanks used for grinding, with the front surfaced already finished, but the back unfinished. No power is in the lens until processed.

The first key is knowing what your lab uses.

[Barry Santini]

To Sharpstick777s point:

I've NEVER had a non-adapt with a FINISHED, stk progressive lens...especially when the DV is PLANO.

FWIW

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[huskypaul]

Thanks everyone for the replies. Thanks Eye Care Rich for the warm welcome too. Thanks DanLiv for the link to Darryl's article. Still working through it, good stuff.

Barry, I could be wrong, but from what I gather from your original post here, you don't see value in FF SV for simple SPH corrections? Also, about your last post, does that mean you wouldn't fit anyone in FF poly? I know, Trivex is the superior option, but just curious.
Huskypaul, so you recommend even low power corrections done in FF? I admit, I'm new to this, but it seems to me that it shouldn't make much of a difference for low powers when the cyl is low or not needed.

I won't speak to anyone's specific dispensing skills but I have my patient wear their new lenses at the dispensing table, where I present them with a lap top, a book and two identical calculators spaced about 3 feet apart. The later I do, to show the patient that they can sit at a desk see the two calculators, keys and all without moving their head. I do an additional exercise and have them look out our window about 1 block down and with their head still I ask them too move their eyes laterally across the surface of their lenses. If my patients did not rave about the increased field of vision along with increased clarity/performance of FFSV I would not be selling them. I can only tell you that we have had great feed back from our single vision wearers most of them are contact lens wearers who are accustomed too a larger viewing area with contacts.

[rdcoach5]

To Sharpstick777s point:

I've NEVER had a non-adapt with a FINISHED, stk progressive lens...especially when the DV is PLANO.

FWIW



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You've never had a non-adapt with a finished stock progressive lens? Never? Do you only Rx Definity or Individual?