A patient came into our office today with Rx of:
+4.50 -5.50 X107
+4.50 -5.50 X071
She is wanting to order High Index Plastic lenses with Anti-Reflective treatment and Brown Photochromic lenses, however I'm having trouble finding lenses available for her rx that fit that request.
Do you have any lens suggestions and/or success stories for a similar scenario?
Thanks much!!
You can get either 1.60 or 1.67 in Single Vision (I'd probably go 1.60 for better optics) in a Transitions Brown, and add your A/R of choice.
In addition, both of those are also available in a Shamir Autograph II Single Vision Free Form (max cyl is a -6.00, so you're good).
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Ditto :D Walman/Solderberg in the Cities should be able to help you with this.Originally Posted by WFruit
This sounds like a job for a Zeiss SV Individual with PureCoat!
(I wear 1.67 and have no problems with it, by the way.)
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I can make that in a 1.80 glass laminate.
Depending on frame size, you could even do it in Trivex for really good optics.
Clinton Tower
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Thanks everyone for your help! I'm going to look into the Auto II or the Zeiss Individual, but pricing might be an issue for my patient.
Dude. AWESOME. I have long been fascinated by the possibilities of high-index glass, for purely selfish reasons...
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*shrug* And we could do it in a 1.80 glass non-laminate.....or even a 1.90 glass. It's not any harder than doing it in any other material. I've never understood why some materials are more "special" than others.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
The reason for the laminate is to get the PBX the patient requested, otherwise it would be non-laminated. I haven't used any 1.90 glass because of the hideous abbe number (worse than 1.80) and from what I've heard, it can't be hardened.
A 5.50 cylinder would physically be 3.62 because of the index. (65.8% reduction)
I have a similar RX I'm working with today. A 16 year old girl with a +5.50 -6.50 and +5.50 -3.50. YIKES!! Someone put her in a Polycarbonate a few years ago and she says she never wears them. Gee..I wonder why? I thought about a Trivex. The optics will be way better but it isn't going to be any thinner or lighter so I'm going with a SV 1.67 Aspheric..still haven't decided what AR to use or what AR I can use on this particular RX with those parameters. Opinions??
With that kind of cylinder power, these patients should really be wearing an atoric lens design or a customized free-form lens design, preferably in a lens material with a relatively high Abbe value.
Best regards,
Darryl
Darryl J. Meister, ABOM
Keri: Put the patient in toric contacts, she will love you forever. Or at least for the next ten years or so when she begins to think CL's are so routine on-line is good enough.
Chip
Whose 1.80 are you using? X-Cel's 1.80 glass abbe is 25 while 1.90 (Zeiss Lantal) is 31......
I'd go Trivex or 1.60. Trivex will still be lighter and either would be better optics. As for A/R, why does the Rx matter which A/R you choose?
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
She actually is predominately a contact lens wearer already. I believe she wears XR's..don't know which brand. I will probably either do a 1.60 or 1.67 with Avance. I would LIKE to think that if I put her in a nice pair of glasses that she really likes, it will promote her to wear them more.
I tried ordering the patient's lenses in the Zeiss SV Individual, but the lab called and said that they could not make the lenses with the patient's cyl power. The lab recommended a regular 1.67 lens.
If the Zeiss won't work, I'd go with the Shamir Autorgaph II then. 1.60 or 1.67 (either with the Trans Brown).
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
Thanks :o)
For extremely high cylinder powers, the curves vary rapidly in height on the back surface, which means that the free-form cutting and polishing tools must also move very rapidly. The machining kinematics involved make it increasingly difficult to maintain an accurate, quality lens surface. Because ZEISS lenses are held to strict quality and accuracy tolerances, some extremely high combinations of sphere and cylinder power may fall outside of our range of acceptable product quality. Some manufacturers do not place such constraints on the quality of the finished product.I tried ordering the patient's lenses in the Zeiss SV Individual, but the lab called and said that they could not make the lenses with the patient's cyl power
Best regards,
Darryl
Darryl J. Meister, ABOM
I really appreciate you explaining the lens surfacing to me, Darryl.
A couple of years ago, a Zeiss rep stopped by our office to tell us about the upcoming Individual Lens. He equated Basic & Digital PALs to Target "one-size-fits-most" shirts versus getting a shirt tailor made to fit my measurements. It was a good analogy and I've used it with some patients, however if the patients who would NEED a "Tailored Shirt" can't get it, what good is it to offer it to patients using that analogy? Is there a better way to explain or recommend Free-form lenses to our patients? Is there a Free Form that you would recommend to "complicated rx patients" and is there a place online where I can go to find out what lenses/materials/add-ons are available for complicated rx's?
Thanks in advance for your help and advice!
Here's Seiko's take on it, specifically their SV Free Form:http://seikoeyewear.com/product.cfm?prodID=12
All of the big 4 Free Form companies (Hoya, Zeiss, Seiko, Shamir) use the "tailor made shirt" ananlogy, and it's a pretty good one.
The main issue with higher sphere/cyl powers isn't the lenses or the software, it's the generators cutting the lenses. Mechanically they can't cut the really high curves yet. The Rx you've given just falls into Shamir's range, and I've found out I could also do it on Seiko's FFSV lens as well, despite that they say the max cyl is 5.00.
There are rules. Knowing those are easy. There are exceptions to the rules. Knowing those are easy. Knowing when to use them is slightly less easy. There are exceptions to the exceptions. Knowing those is a little more tricky, and know when to use those is even more so. Our industry is FULL of all of the above.
The best way I have found to present free form lenses is to say something along the lines of "I'm recommending (because I'm the professional) you get these fully customized progressive lenses (the key word is progressive, which patients understand now-a-days and know is what they want/need). A new manufacturing technology is now available that allows us to custom design your progressive lens (This implies that since we can do this, there is no reason not to do this) so that it by far out performs any lens that was previously available. This is still a progressive, so you will still see blurry areas, etc, but the difference is that it will actually be comfortable."
In the rare occasion where the patient just simply can find no way to swing the cost, then I explain to them that we can still utilize the same manufacturing technology in an "optimized" version of the lens, instead of "customized."
As for High cyl, if you are uncertain how best to handle the Rx, call your lab before you even open your mouth to the patient so that you are armed with the necessary knowledge to present the best visual solutions to your patient.
Trivex too, with the SV Auto 2 now position-of-wear optimized.
There's really not much to choose from when the cyl is > 4.00. Although the Rx looks like it might be thick, notice that the thickest part of the lens at the top and bottom, the vertical meridian, where most contemporary frames have their shortest distance (the boxed 'B' measurement). I wouldn't hesitate to use Trivex in a modestly sized frame.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Unfortunately, even if the generator can cut some of these high cylinder power combinations, a soft lap polishing process cannot apply uniform pressure across the entire surface consistently. This results in errors from the desired shape of the surface and local undulations in power or "waves." So, you can make a lens in this case, just not a very good one. This is why some free-form lens suppliers can still "fill" some prescriptions, although others may decline to do so.The main issue with higher sphere/cyl powers isn't the lenses or the software, it's the generators cutting the lenses. Mechanically they can't cut the really high curves yet.
Best regards,
Darryl
Darryl J. Meister, ABOM
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