# Optical Forums > Ophthalmic Optics >  Searching for ideas from lens wizards! - multifocal over contacts

## shosh

Our patient has a brain tumor that has eliminated most of her superior central vision.  She has been fit with contacts for DVO so she can use her good peripheral vision.  She would like glasses to wear for various near/intermediate tasks over her contacts.  She wants a +3.75 for crafting, +2.00 for reading, and +1.50 for computer.  AND she wants it all in one lens!  Line or no line doesn't matter; but she also plans to look over the glasses for distance.  

I personally would suggest a pair for crafting and another for computer/reading, but she's a pilot (just for an idea of her personality) and won't listen to explanations of how the optics wouldn't work for that.  We already discussed using a PAL at +1.50 sphere with a +2.25 add, but then her reading zone (+2.00 effective power) would be such a small zone of the lens that it would be fairly useless for extended near tasks.  

Any suggestions from all the super opticians out there?  Or is this simply a 2 pair solution and our pilot with the brain tumor will have to face optical reality?  Thanks in advance for any tips/ideas!

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## mervinek

My opinion is that it would be a multiple pair solution.

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## Robert Martellaro

> Our patient has a brain tumor that has eliminated most of her superior central vision.  She has been fit with contacts for DVO so she can use her good peripheral vision.  She would like glasses to wear for various near/intermediate tasks over her contacts.  She wants a +3.75 for crafting, +2.00 for reading, and +1.50 for computer.  AND she wants it all in one lens!  Line or no line doesn't matter; but she also plans to look over the glasses for distance.  
> 
> I personally would suggest a pair for crafting and another for computer/reading, but she's a pilot (just for an idea of her personality) and won't listen to explanations of how the optics wouldn't work for that.  We already discussed using a PAL at +1.50 sphere with a +2.25 add, but then her reading zone (+2.00 effective power) would be such a small zone of the lens that it would be fairly useless for extended near tasks.  
> 
> Any suggestions from all the super opticians out there?  Or is this simply a 2 pair solution and our pilot with the brain tumor will have to face optical reality?  Thanks in advance for any tips/ideas!


Off the top of my head I'd consider a +.50 add multifocal with +1.50 on the top and a +1.75 chem clip over. 

WRT the superior quadrant vision loss, show the client the effect on the vision with yoked base up prism, starting with about 10∆ BU in each eye. This will move objects that are above the straight ahead gaze downwards into the straight ahead gaze.

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## smallworld

I would recommend r/o multiple pairs with different plus powers.  With central vision loss I can't imagine a PAL working at all.  Or Robert's idea with a FT45.

I had a patient with a brain tumor with central vision loss also.  The prism idea is a great idea.

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## rbaker

She was a pilot. with any scotoma she would not meet the FAA's requirements for even a Special Issuance 2nd Class Medical Certificate.

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## optical24/7

1/2 eye w/trifocal.

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## Paul Smith LDO

> 1/2 eye w/trifocal.


+1, I made one for a patient a couple of years ago in an 8x35 and he still loves em.

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## uncut

> 1/2 eye w/trifocal.



Agreed, and with Paul...........the high add will be more accurate in placement, and with a B dimension of at least 34 mm......a functional product. :Biggrin:

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## Robert Martellaro

It won't work, unless we could get a trifocal with 22% of the add in the intermediate, which we can't. The seg would also be too high and interfere with a desk top monitor. Look at the requirements again, +1.50 for the monitor, +2.00 for book/tablet/desktop, and +3.75 for crafts.

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## optical24/7

> It won't work, unless we could get a trifocal with 22% of the add in the intermediate, which we can't. The seg would also be too high and interfere with a desk top monitor. Look at the requirements again, +1.50 for the monitor, +2.00 for book/tablet/desktop, and +3.75 for crafts.


A Franklin trifocal!  :Cool:

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## Diane

> A Franklin trifocal!


Bingo.

Diane

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## Robert Martellaro

> A Franklin trifocal!


That would provide the powers, but ergonomically speaking the first segment would be too high for a desktop monitor. Weight and manufacturing costs are additional considerations.

If a power layer Chemistrie Clip is rejected by the client as too inconvenient, a simple work around would be to equalize the work distances somewhat, that is, the monitor and reading distances, and use approximately  +1.75 on top, letting the depth of focus and reserve accommodation take up the slack.

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## optical24/7

> That would provide the powers, but ergonomically speaking the first segment would be too high for a desktop monitor.


Robert, wouldn't that depend on the B dimensions and seg hgt placement along with being a 1/2 eye, variability worn up or down the nose? 

 [/QUOTE]Weight and manufacturing costs are additional considerations.[/QUOTE]

Could conceivably be done in trivex, cost would depend on if you can do them in house yourself. 

[/QUOTE]If a power layer Chemistrie Clip is rejected by the client as too inconvenient, a simple work around would be to equalize the work distances somewhat, that is, the monitor and reading distances, and use approximately  +1.75 on top, letting the depth of focus and reserve accommodation take up the slack.[/QUOTE]

I'm a big supporter of chem clips and have done some outside the box clip designs. It should definitely be on the table for consideration.

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## AngeHamm

How is this person legally a pilot with her vision that dramatically compromised????

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## Robert Martellaro

> Robert, wouldn't that depend on the B dimensions and seg hgt placement along with being a 1/2 eye, variability worn up or down the nose?


It would. I can't picture a half-eye with enough depth for a trifocal though, where minimum usable heights are about 18mm. Sliding the frame down the nose to clear the top segment when looking at the monitor probably places the topmost eyewire in the way. Success depends on frequency of use I would think. Modifying the work distances and simplifying the lens design will provide much greater field of vision both vertically and horizontally. Case by case I suppose. 




> Could conceivably be done in trivex, cost would depend on if you can do them in house yourself.


Edge-to-edge bond? Not by me!




> I'm a big supporter of chem clips and have done some outside the box clip designs. It should definitely be on the table for consideration.


You and Barry sold me on the concept. It's not to often we see new products that are properly engineered right out of the box. Thanks for sharing your skills and knowledge, making us all better ophthalmic opticians.

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## rbaker

> How is this person legally a pilot with her vision that dramatically compromised????


As I pointed out in post #5 above, she is not legally exercising the privileges of an aviator or , in fact, any air crewman. Either she has not reported her condition to her AME or has not had a required physical from her AME to disclose this change in her physical condition. What she is probably referring to is the fact that she used to be a pilot in much the same manner that I used to run the Boston Marathon back 55 rears ago.

A Franklin Bifocal, Trifocal or even Quadrifocal with any conceivable power, prism and segment width arrangement is a possible solution. Lotsa luck getting one fabricated these days.

In any case, I certainly would not want to share the airspace with her.

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## Uncle Fester

> It won't work, unless we could get a trifocal with 22% of the add in the intermediate, which we can't. The seg would also be too high and interfere with a desk top monitor. Look at the requirements again, +1.50 for the monitor, +2.00 for book/tablet/desktop, and +3.75 for crafts.


Can you still specify seg powers in glass tri's? I know you used to. I miss Mike. (sigh)

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## Paul Smith LDO

> It won't work, unless we could get a trifocal with 22% of the add in the intermediate, which we can't. The seg would also be too high and interfere with a desk top monitor. Look at the requirements again, +1.50 for the monitor, +2.00 for book/tablet/desktop, and +3.75 for crafts.


How about a FT 35, with a carrier of +1.75 (+ or - a .25 D shouldn't be problematic)  for monitor and desk top and a +2.00 ADD.  Safilo has a reader; 1321 with a 27 mm B.  She can build model airplanes and everyone is happy.

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## Robert Martellaro

> Can you still specify seg powers in glass tri's? I know you used to. I miss Mike. (sigh)


The range was roughly 40% to 60%.  Glass segmented multifocal powers were determined primarily by using different refractive index glass in the segments. 




> How about a FT 35, with a carrier of +1.75 (+ or - a .25 D shouldn't be problematic)  for monitor and desk top and a +2.00 ADD.  Safilo has a reader; 1321 with a 27 mm B.  She can build model airplanes and everyone is happy.


This is what I proposed in Post #12, reiterated in post #15. 

However, I do have clients who need a +.50 add to go from the monitor to the desktop, usually absolute presbyopes, with work distances of 22" to 26" to the monitor and 16" to 20" to the desktop. A power clip would work well in this scenario, turning the computer eyeglasses into hobby/crafts task eyeglasses in a matter of seconds, without narrowing the field of vision.

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## rbaker

> Can you still specify seg powers in glass tri's? I know you used to. I miss Mike. (sigh)


Its been a long time and I could be wrong but I don't think anyone is fabricating custom segments since all the companies that used to do this work no longer exist. 

If you had some spectacle crown glass rough blanks and a few inches of the appropriate hi-index barium crown bars, a hand pan, a lap cutter and a furnace you could produce these semi finished multifocal yourself. There might be some old timer out there that could provide you with what you need. I saw this custom work done at AO in Southbridge back in 1955 when I was an after school part time pud knocker there. One Optician could fabricate a pair in a about four hours of direct labor. No big deal.

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## Chris Ryser

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## ml43

> Check out :
> 
> Diverse Optics provides strong in-house engineering support backed by solid strategic partnerships with leading polymer optics designers. We offer a wide array of engineering services including optical design, opto-mechanical design, mold design, mold flow analysis, and pre-production cost analysis. You also benefit from a team that has the knowledge to ensure your products are robust and suitable for large-scale manufacture.
> 
> 
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I don't think anyone in the opthalmic industry is willing to pay for custom precision optics.

Only lens/contact lens manufactures can afford it

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## rbaker

A single mold to cast a multifocal lens would cost in the thousands of dollars.

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## ml43

> A single mold to cast a multifocal lens would cost in the thousands of dollars.


Tens of thousands, depending on complexity.

A polymer prototype isn't much cheaper

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## shosh

Thanks to to all for your input!  We are planning to offer the patient the split option of a +1.75 top with a +2.00 bifocal to be worn over contacts, or look further into a +1.50 top with a +0.50 add bifocal with the +1.75 clip that can be placed over the top for her crafts.  I appreciate you all taking the time to share your expertise!

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## MakeOptics

Robert don't give away all the good secrets Chemistrie for LV has been a god send.  Multiple clips for multiple needs, you can put bifocal on the clips over bifocals in the lens.  The options are phenominal.  The best part is the case that holds those multiple clips.

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