Lenticular Lenses and PALs, Need Help!

Hello everyone. I have a problem that I have no experience with and need advice.My pt came in with half-busted/broken bubble type lenticular lenses shoved into a sunglasses frame on its last leg. The pt said the lenses were 40 years old and I have no experience with lenticular lenses. She said she wanted to see distance , computer and near and didn't want the bubble anymore. My thought was let's put her in a non-compensated pal so to accommodate her wishes and make it look better. Pt is a +13.00 with a +3.00 ADD OU. Pt called and said she couldn't read and I'm not too sure what to do here because her rx was double-checked, seg placement was dotted lower edge of pupil and pd came out correct. She's in a Shamir Intouch 15 w/a seg of 24 in a 1.74 material. Does anyone have any idea what's going on or what I can do?? Does a lenticular lens just have one distance or is it a multifocal?? When not wearing her glasses she wears sv RGP CL's. Any help would be greatly appreciated.

What lab did you use?

What's the diagnosis?

Reduced acuity?

Outside Rx?

Vertex distance?

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Originally Posted by drk

What lab did you use?

What's the diagnosis?

Reduced acuity?
Outside Rx?

Vertex distance?

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Walman Toledo
hx of Aphakia bilateral, bilateral open angle glaucoma- mild
BCVA 20/30 OD 20/200 OS
Inside RX
vertex of 11

A lenticular can be a single vision or a bifocal in round style or ft22. If you look at her old lenses you can see the the seg if it is there. With a high Rx like I doubt she could wear a progressive. Think about how much prism you are creating at near. Lenticulars were made the oc 1.5 above the seg to reduce prism at near. Why don’t you fit her with a progressive to wear over her contacts.

RED FLAG ALERT ALERT ALERT!!!


Just not a candidate for progressives.

She needs a bifocal and second single vision computer only pair.

If she has not worn progressives before you are probably in deep do-doo thinking you can make this rx in any progressive.

Some of the guru's here might be able to fit her but I wouldn't as I have to answer to others.

I've consulted with my lab after your suggestions, thank you very much for helping me. I had no idea, but now I know if a pt has a lenticular they have to stay in one.

Remember the power changes if they slip down their nose even a little bit- so a perfect frame fit counts!

Pre-adjust the bifocal frames and if they still slip with a gentle tug find another frame.

If a single vision computer pair slips a little you can get away with a little less plus when ordering.

Ask the prescriber if the +3.00 add can be reduced.

Remember the add on the outside of a high plus is already increasing the power from increased thickness and vertex distance.

Use a CR-39 material with a good AR. Guru's are welcome to fire away but this is my sure fire way of eliminating hi index as the source of vision complaints.

Reverse the glasses for an accurate lensometer reading.

Lensman11- Are Blended Lenticulars available in tk's? It's been a long time since I've ordered one.

Good luck and keep us posted with the final results! :smile:

Also, if she's used to RGP wear, her vision will *never* be "as good" in that Rx with a spec lens - SV or otherwise. Has she considered wearing the CLs, and then have the doc figure an over refraction? PAL might work then...

Also remember how to read an add on a high power plus lens: turn the frame around on the lensometer.

Remember that a nice 42 eyesize frame is going to make mega-difference in whether she has to do a lenticular or not. I'd look for a teeny retro frame.

Fester brings up a good point re: desktop computing: slide them down a few millimeters and she'll get a nice +0.50 or more.

Blended lenticulars were available in round segs emphasize were. When telling someone to turn the glasses around for an accurate reading you should be more specific. You turn them around to find the true power of the seg only. Turn the glasses around read the distance power (it will not read the power you ordered) read the power thru the seg while it is still turned around the difference between the two is the power of the seg. Check the distance power normally for accuracy. This procedure should be done with any multifocal where the seg is on the front. That would include all plastic and glass multifocals. The only exception used to be some forms of Ultex bifocals where the seg was on the back and the lenses were made with +cyl. Today the exception is all free form progressives as the add is on the back.

I'd discuss the option to keep the rx single vision and just slide them down her nose a little to use at computer and near.

I'd put that out there for a patient in this power as it simplifies a lot of things.

And like drk suggests Crystal- insist on a small frame and a proper fit. This is a function first patient.

Let them walk if they want to dictate frame choice here.

I'm just noting best corrected vision. You are really only correcting one eye and that vertex distance of 11 is, I think, achieved for about 10 seconds of wear until they slip;) Prefit the frame and check for that.
:smile:

Agree with Fester. I was just bringing the vertex distance issue into focus, but as he says, find the frame and measure the vertex distance and compensate the 11mm-refracted (man, that's close) Rx.

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Originally Posted by drk

Agree with Fester. I was just bringing the vertex distance issue into focus, but as he says, find the frame and measure the vertex distance and compensate the 11mm-refracted (man, that's close) Rx.

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Crystal- You really don't need to calculate this as it will be obvious to the patient when the intermediate or near focus occurs and they probably already are doing it.

Are you sure that 11mm vertex is not going to have her eye lashes touching the lens when she blinks?

Here's a calculator to experiment with that will show you how powers will change (and quickly!) with vertex distances in this power.

http://216.144.236.77/tools/vertex.php

Quote:

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Originally Posted by Crystalpluto

Hello everyone. I have a problem that I have no experience with and need advice.My pt came in with half-busted/broken bubble type lenticular lenses shoved into a sunglasses frame on its last leg. The pt said the lenses were 40 years old and I have no experience with lenticular lenses. She said she wanted to see distance , computer and near and didn't want the bubble anymore. My thought was let's put her in a non-compensated pal so to accommodate her wishes and make it look better. Pt is a +13.00 with a +3.00 ADD OU. Pt called and said she couldn't read and I'm not too sure what to do here because her rx was double-checked, seg placement was dotted lower edge of pupil and pd came out correct. She's in a Shamir Intouch 15 w/a seg of 24 in a 1.74 material. Does anyone have any idea what's going on or what I can do?? Does a lenticular lens just have one distance or is it a multifocal?? When not wearing her glasses she wears sv RGP CL's. Any help would be greatly appreciated.

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Quote:

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Originally Posted by Crystalpluto

Walman Toledo
hx of Aphakia bilateral, bilateral open angle glaucoma- mild
BCVA 20/30 OD 20/200 OS
Inside RX
vertex of 11

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My bold.

High index (low Abbe) lenses at this power will have about .3∆ of lateral (transverse) chromaticism at 15˚/8mm off-axis, and .6∆ @ 30˚/15mm, too much for usable near vision in a multifocal, especially a PAL. An optimally fit PAL might supply usable distance vision, with marginal intermediate vision under good light. Near will be MIA. Monocular vision reduces the chances of success substantially. PALs should be off the table.

Aspheric lenses are required to reduce oblique astigmatism with powers over 8 D. I doubt that there are any aspheric lenticular blanks still be being made (Aire-O-Lite is spherical only).

Instead, use an aspheric blended lenticular multifocal for distance and near (Super Modular by Essilor), with a separate pair for intermediate/near. CR39 only. Fit on center or at most 2mm in, selecting a nearly round frame and optimal bridge fit with temples that do not interfere with the lateral gaze.

Consider a fitover sun solution for the polarization and excellent light seal.

Hope this helps,

Robert Martellaro

Oooh. He went there and got specific. He may have done one of these in the past 10 years, unlike me...

Quote:

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Originally Posted by Uncle Fester

Crystal- You really don't need to calculate this as it will be obvious to the patient when the intermediate or near focus occurs and they probably already are doing it.

Are you sure that 11mm vertex is not going to have her eye lashes touching the lens when she blinks?

Here's a calculator to experiment with that will show you how powers will change (and quickly!) with vertex distances in this power.

http://216.144.236.77/tools/vertex.php

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Hey, I meant that she should fit the frame for distance position and figure out how far away from the old eyeball it's going to be, then correct the Rx for POW.

Quote:

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Originally Posted by drk

Oooh. He went there and got specific. He may have done one of these in the past 10 years, unlike me...

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Hi K,

Right before the pandemic- age 25 with congenital aphakia, which is about all we'll see nowadays. Same scenario as the above- he said they were the first pair of eyeglasses that were comfortable to wear visually. Night and day difference. Fitted hundreds in the 80's, mostly for those still alive, but were ahead of the technology, and couldn't wear CLs (not too hard to fit due to no residual).

Best regards,

Robert

You make an interesting recommendation regarding temples, and I want to see if I can figure out why.

I know that high plus lenses cause the dreaded "jack-in-the-box" phenomenon, meaning that there is literally an annular blind spot that the lenses cause (due to prismatic effect) that can make things "pop" into view, suddenly as they come from, most typically, the lateral sides. (Conversely, looking through a high minus lens is like looking through a door-peeper: big field of view.)

Are you trying to maximize peripheral vision by minimizing the thickness of the temples so the patient can track what's coming, ASAP?

Quote:

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Originally Posted by drk

You make an interesting recommendation regarding temples, and I want to see if I can figure out why.

I know that high plus lenses cause the dreaded "jack-in-the-box" phenomenon, meaning that there is literally an annular blind spot that the lenses cause (due to prismatic effect) that can make things "pop" into view, suddenly as they come from, most typically, the lateral sides. (Conversely, looking through a high minus lens is like looking through a door-peeper: big field of view.)

Are you trying to maximize peripheral vision by minimizing the thickness of the temples so the patient can track what's coming, ASAP?

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Yes. SOP for monocular vision in my book. Here's a nice visual representation of the scotoma, and how the vision is in, then out due to the scotoma, then back in with an additional head turn.

Nice diagram! ^^^ Here's mine:

https://encrypted-tbn2.gstatic.com/s...ffoOg&usqp=CAEhttps://encrypted-tbn0.gstatic.com/s...wP6Iz&usqp=CAE (Jack in the box/glasses...HAHAHAHAHAHA)