1.67 or poly?

[Diane]

Trivex on the OD and 1.67 on the OS.

Diane

[fjpod]

you are correct, the proper verb1age of the punchline is: stays up all night pondering the existence of dog.

[B101875]

Remeber you are the Optican. You can always tell the pt you can't do your Rx in this Frame. You need to be in a Full-Metal.

[pseudonym]

Me, I would put 167 In O.S. and something with much lower index in O.D. There is no law that both lenses must be of the same material. Do this all the time to get decent cosmetics and weight, never had a problem. Many opticians seem to think this is a forbidden technique for some reason.

After making calls to the lab to explain the situation, they told me to make two invoices: one with frame and right lens only in poly, one with left lens only (no frame) in 1.67.

They came today and were dead on accurate for every parameter. The string was right down the middle- someone really worked hard to make this job look nice. The CT was almost the same in both. He picked them up and was DELIGHTED. Best dispense ever. He said it was the first pair he could remember that didn't make him feel cross-eyed. When he got over the vision issue, he looked at himself in the mirror and practically hollered "my eyes ARE the same size!" The left eye in his old glasses appeared markedly bigger through his old lenses.

All together a most satisfying dispense. Thanks for the advice, especially Chip. It occured to me to mix indices, but I wouldn't have gone to the lab with the problem if you hadn't said you had done it before with success.

[shannon]

I wish I had some of the tools you are offering, but I don't. I cannot specify base curve. I went with Chip's suggestion of using differing materials and will keep the old fingers crossed that it works out. It was a royal PIA to work it out with the lab, and I hope they don't get their right and left mixed up. The man said he has never had a pair that didn't make him feel cross-eyed.

It's true what was said above about people always wanting the frame that is least suitable. Sometimes I let them pick a few and tell them the computer says the unsuitable frame won't cut out, sorry. But this guy absolutely wouldn't budge on the semi-rimless.

Is it your software that won't allow you to specify B.C? If so, can you call the lab to request what you want?

[pseudonym]

Is it your software that won't allow you to specify B.C? If so, can you call the lab to request what you want?

Maybe, I haven't tried it. But I'd have to know a heck of a lot more about base curves myself before asking them to do something special like that.

The lab is a profit center, understaffed, and crazy busy. I really wanted this job to go well, so I came here to find out how to make it functional and attractive. Got a big win on both counts.

CR-39 would have been my first choice for the weak eye, but the lab has rules about semi-rimless. The rule is NO CR-39 in semi-rimless.

[Wes]

That's a good rule.
As far as base curves go, Braheem gave you an excellent suggestion. Look up corrected curve theory, image magnification, and iseikonic lenses.

[Now I See]

This has been an enlightening thread! Honestly, I never thought about using a different index in each eye, learn something new everyday!

Glad it worked out, Pseudonym! I love a happy ending!

[pseudonym]

I don't know how happy the ending was. I sort of got chewed for doing it. Apparently, if the guy loses his left eye due to having a lesser impact resistant lens on that eye (1.67), I can be sued, my company can be sued, the lens manufacturer can be sued, my boss can be sued.

Couldn't go with Trivex, though. We don't sell it.

[Tito]

For this Rx I would prefer a 1.7 index lens in a small frame with a FF aspheric lens with an eliptical cut out lens.

[Tito]

I would also increase a litlle bit the center thickness of OD lens to make it look similar to the OS and also sugest a closed metal or acetate frame

[Wes]

Pseudo, Using that logic you can get sued every time you don't use poly. Im calling bs on your boss. S/he probably doesn't understand what or why you did what you did and became uncomfortable. Not wanting to put his/ her ignorance on display, s/he came at you with lawsuit bs.

[Robert Martellaro]

I thought this was another material war thread, so I begged off. I've read the whole thread now, and FWIW, here's my two cents.

• Speculation concerning aniseikonia is just that- speculation. Leave the diagnosis to the OMD/OD, otherwise you might create what you're trying to avoid, especially if the anisometropia is habitual.
• How safe the lens should be depends on many factors, but the first thing I think about when I see an Rx like this is if the client is amblyopic, and if so, the degree of vision loss.
• The OCs should be placed level with the client's pupils to minimize VI, assuming healthy eyes.

[drk]

Second that on the amblyopia. It's pretty 50/50 that the OS is 20/60 or so.

As to iseikonic design, if you use equal bases and centers then you get minimized magnification difference. That's a no-brainer. Braheem was doing one better...trying to offset the magnification difference. That is a little bold, but I doubt anyone's going to call you on it. Would be a nice professional courtesy to call and discuss.

As to using different lens designs: I wonder if the difference in the asphericity design between two lens manufacturers would matter? Would it? Is it too minimal to worry about? Would FFSV (as Barry said) just maximize each lens individually with the same "scheme"?

[Tito]

The asphercity between different lens manufacturers matter(unless it is Free form from same Lab)as well as different base curves and Abbe from the different materials,specially if combined with Poly.

[pseudonym]

Bottom Line: The man was thrilled and nearly pumped my hand off shaking it. If he plays with BB guns, I hope he aims for the right eye.

I did actually ask my boss if pulling defeat from the jaws of victory was a phrase that meant anything to him.

[TCurtisOli]

Aspheric 1.67-no poly-EVER!!!!! So bad.