Narrow frame addiction and currents thoughts in FF progressive design

[Barry Santini]

I understand from several labs that specialize in DS FF progressives that they many companies are "tweaking/adjusting" their corridor designs after analyzing progressive redos and non-adapts.

It would appear that their is a statistically-significant correlation between the longer corridors (which we ECPs had formally thought were superior to "short" corridor versions) and redos/non-adapts.

Me thinks the following:

For years now, the fashion in eyewear has been all about narrow "B" rectangles. And we've apparently been "too" successful in using any number of conventiona, fixed but shorter corridor length progressives to fit into our client's frame fashion desires.

The good news is it worked.

The bad news is they've gotten used or developed habits favoring less eye depression angle.

This then are the reasons, I'm goning to speculate, behind the need to tweak the corridor length on the DS FF progressive algorithyms - especially the ones position to "fit" the progressive to the frame. This is important to appreciate, now that "B" dimensions are on the rise.

FWIW

Discussion?

Barry

[rbanting69]

We have been using the Shamir Autograph II's exclusively for all our patients. We have had a tremendous amount of success using the next shortest design compared to the actual seg ht. We also bump the add on hyperopes to compensate for the program weakening the total power in the reading. I am very impressed with this product.

[Uncle Fester]

I'm doing the same thing.

Kicking the add depends on what they were in before. My doc's are in the habit of giving 2 adds. One for svn/FT and one .25 stronger for PAL's. I'm trying to get my doc's to stop doing it for first time progressives especially. Established presbyopes I find expect the add power change however. If the distance increases in plus decreases in minus a quarter though, I'll go with the weaker add.

[Robert Martellaro]

I understand from several labs that specialize in DS FF progressives that they many companies are "tweaking/adjusting" their corridor designs after analyzing progressive redos and non-adapts.

It's about time. Most baby boomers, myself included, are old enough to need Adds over +2.00, and we're getting tired of having to tilt our heads back for what seems to be just about everything we do except driving!

It would appear that their is a statistically-significant correlation between the longer corridors (which we ECPs had formally thought were superior to "short" corridor versions) and redos/non-adapts.

Statistics, scmishtics, we've got sore necks goin' on here!

Me thinks the following:

For years now, the fashion in eyewear has been all about narrow "B" rectangles. And we've apparently been "too" successful in using any number of conventiona, fixed but shorter corridor length progressives to fit into our client's frame fashion desires.

That's part of the problem, I think.

The good news is it worked.

The bad news is they've gotten used or developed habits favoring less eye depression angle.

I believe F. Kozol (1996- Compensation procedures for the Anisometropic presbyope) found that the average reading depth for a single vision wearer is about 8mm. Even short corridors don't have the full power at that point, but emerging presbyopes probably adjusted due to reserve accommodation, and their greater depth of focus.

This then are the reasons, I'm goning to speculate, behind the need to tweak the corridor length on the DS FF progressive algorithyms - especially the ones position to "fit" the progressive to the frame.

Yes, especially those. Moreover, back surface PALs lose about 1mm due to the increased ocular rotation needed to get into the full power compared to front surface designs.

This is important to appreciate, now that "B" dimensions are on the rise.

Very much so, especially when the corridor length is determined by the software instead of the optician. Check out my post above in the "lifting frame thread".

[DragonLensmanWV]

I'm doing the same thing.

Kicking the add depends on what they were in before. My doc's are in the habit of giving 2 adds. One for svn/FT and one .25 stronger for PAL's. I'm trying to get my doc's to stop doing it for first time progressives especially. Established presbyopes I find expect the add power change however. If the distance increases in plus decreases in minus a quarter though, I'll go with the weaker add.

And I recommend with your higher myopes to go with the stronger add.