Does it exist?

[scriptfiller]

I have a pat. ,who is a pilot, needs basically a trifocal double seg. Does such a lense exist?

Thanks!

[obxeyeguy]

It's called a quadrifocal, and the only one I se listed is by Vision Ease in glass.

[Wes]

hmm

Back in my school daze, I made a few quadrafocals, as they called em, where you basically had a double d where the bottom was a trifocal and the top was an upside down bifocal "D" seg. I've never seen a double trifocal. Doesn't mean they don't exist. Someone will be along to answer your Q. You might want to clarify exactly what you need.

[Jacqui]

If it can't be found, it could be made using the same technique as a Franklin bi.

[Fezz]

If it can't be found, it could be made using the same technique as a Franklin bi.

Renegade!!!!
:cheers:

[obxeyeguy]

There would be absolutely no use at all for a tri on the top and the bottom, period. Think about fitting, there would be no distance area to work with to make them work properly, maybe 5 mm for distance.:hammer: Bottom tri, top intermediate, deal with it.

[YrahG]

It might be possible to have a FF lab surface a back side round seg onto the top of a trifocal, this would accomplish what you need and allow you to specify the add power int eh top segment as well as open up the material options. The power of FF.:cheers:

[obxeyeguy]

If it can't be found, it could be made using the same technique as a Franklin bi.

To add to this, just because we can, does not mean we should, ever. Hold true to what we do, and what we know.

[rbaker]

It's called a quadrifocal, and the only one I se listed is by Vision Ease in glass.

I got my last pair of blanks from them about 15 years ago. The upper add was the same power as the intermediate. To my knowledge there was never a plastic lens produced in this form but glass is superior in this use anyway.

[sharpstick777]

I have a pat. ,who is a pilot, needs basically a trifocal double seg. Does such a lense exist?

Thanks!

I have done occupational bifocal for pilots, but for the life of me I can't understand why he would need to read at 18" above his head, its usually intermediate only vision there because the top instrument panel usually sits at about 42"-58" inches.

You may check out Quest Optical Lab, they make a special pilot lens too, basically, if Quest doesn't make it, no one does.

http://www.questopticallab.com/pilots.html

Also, with a double tri, and counting the space between segments, I would need minimum a B measurement of about 51mm to make it work, I have not seen a frame that big in years. If you could do it in glass, it would weigh so much the guys face would be at his knees by the end of the day.

I have used standard double D's with much success..

[scriptfiller]

Thanks for the responses. I looked-up the price for a Quad. from my lab.... the cost of the lense is more than what we billed the pat. for the entire order. I'll have to see if he wants to shell-out some serious bucks to do it. Also, the top segment would be a bifocal seg not a trifocal seg.

Thanks again for the responses and commentary, Optiboarders rock!

[Uilleann]

What kind of pilot is he exactly - and what type of A/C is he rated for again? I'd stay well out of his airspace from the sound of his lens wish alone! Yikes!

[WFruit]

I'm willing to bet that a press on add would be a lot cheaper for the top portion.

One of my instructiors (3rd year I think) when I was in school for my license had a progressive with a press on add at the top. Because he could..... come to think of it, he was a little out there.....

To add to this, just because we can, does not mean we should, ever. Hold true to what we do, and what we know.

What we do is serve our patients to the best of our ability with what we know. If it can be done, and the patient is willing to wait the time it takes, and pay the money it costs to make, then we absolutely should do it. Every time.

[scriptfiller]

Uilleann,

Flew in Vietnam. Former heavy equipment operator for NWA, retired due to age restrictions. CAP pilot and Cessna 172 owner. A personal acquaintance who I'd love to fly with again.

[rbaker]

Uilleann,

Flew in Vietnam. Former heavy equipment operator for NWA, retired due to age restrictions. CAP pilot and Cessna 172 owner. A personal acquaintance who I'd love to fly with again.

About the only reason he would need a top seg flying a C172 is to see the magnetic compass.