Prisma only for near vision

[Jacqui]

If I ever get smart enough to post pictures and video's on OB, I have a video and stills on how to make a Franklin, almost any Optician do it. Takes some time (an hour or two, not months), No unwanted prism, etc. The beauty of them is you can put the prism and center hights anywhere you want them to be.
Cost? Exactly what the cost of two pairs of SV lenses would be if you don't screw up + your time. You don't even have to have your own edger.


Chip

Yup :))

[gmanlook]

Just use prism segs that are cemented on...I have made many over the years...forget the Franklin...way too much weight. I believe Slabs Plus in Tampa, Fl still does them. Gary

[Jacqui]

I have always found the Franklin to optically horrible. There is often tons of unwanted prism, the segs are never centered correctly inducing unwanted prism in the near, the distance OC is often not centered correct , not to mention the enormous thickness and weight of the lens since its only available in CR-39. I just had 3 remakes on one pair because it was simply not passing ANSI standards. There may have been a time when Franklins could have been made with precision and skill but most of those skilled opticians have retired.

Since I have started in 1994 in Optical I have had more Franklins fail final inspection than any other lens. This patient needs more precision than a Franlkin can provide in my opinion.

If you're having that much trouble you may want to look for another lab. Also, why is it made only in CR-39?? I've made them in everything except Polyc--p.

P.S. ANSI is for amateurs, anyone in the lab should be able to do much better. I won't even allow the term to be used in my lab.

[Jacqui]

Just use prism segs that are cemented on...I have made many over the years...forget the Franklin...way too much weight. I believe Slabs Plus in Tampa, Fl still does them. Gary

The prism segs that are inlaid into the lenses are much better. Franklins aren't that heavy if you know what you're doing.

[chip anderson]

Anyone remember the glass wafer prism? The ones you ground extreemly thin to fit the front curve and cemented with Canadian balsam?


Chip

[Jacqui]

Anyone remember the glass wafer prism? The ones you ground extreemly thin to fit the front curve and cemented with Canadian balsam?


Chip

Yup :))

[snotbagel]

Use 1.67 matched base curve lenses top n bottom. Now the ledge is on the inside and looks better, fits better in the frame. The real art is in making separate top n bottom patterns and hand edging the mating surfaces. I charge $600,as i would for two pairs of sv 1.67 lenses.

[jefe]

If I ever get smart enough to post pictures and video's on OB, I have a video and stills on how to make a Franklin, almost any Optician do it. Takes some time (an hour or two, not months), No unwanted prism, etc. The beauty of them is you can put the prism and center hights anywhere you want them to be.
Cost? Exactly what the cost of two pairs of SV lenses would be if you don't screw up + your time. You don't even have to have your own edger.


Chip

I hope you get smart enough to post videos and pictures soon. I would be interested in seeing them.

[Celso Cunha]

How come the old opticians still come up with the best solution in such a modern age of technology when it comes to difficult cases. How come nobody mentiones that a PAL with a +3.00 add has not much reading area. A first time PAL wearer with such an add is a guaranteed non adapt anyhow.

Really,
With a 3:00 PAL add we can not have good fields of intermediate or near vision.
The evolution of the points made ​​PAL mm binocularly balanced. The introduction of prisms in patients with Tropias surely lose all of that balance.
Perhaps with the future development of Free Form software surfaçagem that will be possible, but do not believe that Kodak has already developed it.

[sharpstick777]

A Progressive may not as efficient for this patient because of reduced visual zones, however, its still the ony solution that will give vision in every range. If we set her in Bi-focal although each zone will be superior, she will lose the entire area of view between 18" and 18 Feet. I don't know about you, but for me, some function in that range is essential. The Key Pad at the grocery store, the prices on the shelves, my speedometer, wrist watch, the computer I am writing this on. Trifocal would help a little true, but in her RX it will be incredibly diffucult still. She still would be "hunt and lunging" as I call it.

Even though a Progressive will not work its best, it still could give this person better vision in that important finger tip range and enable her to function enough with more confidence and enjoyment of life than any other solution. I would fit her in a Progressive without any hesitation, but do it along with a pair or Readers or Computer lenses for those times long term focus is needed.

Even an imperfect Progressive still could greatly enhance her lifestyle, function and confidence because of its unique ability to give her better vision in every range less than 20'.