I recently had a patient who received Comfort Poly progressives with Crizal Alize coating. He came in complaining of an annoying rainbow color effect. Is this chromatic aberration from the Poly or could this be the crizal alize? I am leaning towards the Poly as the major cause. He has not worn poly before (don't even ask me why my optician elected to use poly in this +1.00 patient who has always worn CR39.)
Is it a rainbow effect while looking at the lens or is it on the edge of objects?
Can not understand why switch an older person from CR39 to poly when the CR39 is about the closest to a glass lens you can get. (for a simple RX)Originally Posted by ilanh
I can only put this down a higer priced sale and give a disservice to patient.
One- the rainbow effect can be reflective appearance OR abberation noticed by patient due to poly.......but doubtful.
Chris-
I don't get your attitude on poly!
I have been in every stage of the business for 35 years, now back to opticianry at a busy Ophthalmic practice.
We fit 90% poly here, up to 35 patients daily, and most are over 60 years of age.
Why we fit poly? Airbags, personal safety (active bunch here), and just pure comfort. (and free scratch resistance a plus).
We also sell poly at same price as plastic- not at profit on plastic but as service to our patients (by our doctor's request.
Denny
Sorry, had to run off a minute.
Our poly success has been proven. We have had two non-adapts in past three years due to chromatic abberation.
I DO fit this material with caution- nothing over +/-6.00D unless patient requests the material.
Safety Legitimate? YES. I have had 14 patients hit in face with air bag this past month alone (collisions with deer very high here). Just finished with another. I have seen too many injuries with "other " materials, and want the best for our patients.
3 poly non-adapts a year!!?? Sounds very low. I think that in my practice it is higher. In fact, I have 2 posts this month alone that deal in Poly non-adapts. The other issue is that whenever we fit Poly and have some type of complaint, we often assume it is the Poly (it's easy to blame). A perfect example is the patient who has a perfect refraction (double and triple checked), PD's and base curves are perfect etc who simply "does not see well" from his Poly glasses. You put the same Rx into a pair of trial frames and "it's clear". Therefore, is this type of thing Poly? Crazy patient? Subtle lens distortion that I can't see? I always check everything but always wind up blaming the Poly (perfects unjustifiably). Therefore, I prefer not to use it if I don't have to.
remind me not to drive near where you live. perhaps you need a "drive slower inthe forrest" campaign
I have none. In recent memory I remember one 1.67 non-adapt (base curve) and one 1.56 non-adapt (moved from poly).
I thought your other one was 1.67 not poly.
I would highly suspect the poly. I've worn polycarbonate lenses myself and seen the "rainbow effect" in my peripheral vision. I've also worn Crizal Alize, and liked it very much. I don't personally wear polycarbonate anymore, I wear Trivex. It's just as light, impact resistant, etc. when compared to poly, and I've never seen any rainbows. I'd say either switch the patient back to CR39 or try Trivex.
It's like being a travel agent... I help people see the world!
Drill mount frame, perhaps?
Of course.................drill mounts are the ideal for poly................so are all the related safety aspects.
Dont take me wrong, I am not against poly, it is just that every person might have a different personality from another and not get used easily to something different than what they had for a long time.
Specially when you get older..........you see the difference on all things that are different from what we had forever.
Getting back to the rainbow effect.
I have noticed the same thing on1.60. Talked with the lab and kind of decided it is the difference in index of refraction between lens material and AR coating.
I don't know what the index is on AR, but we only notice it on 1.60.
The only times I have seen "Rainbow Effect" complaints were when I failed to make note of the vertical centers and only on poly single vision (I never fail to note vertical centers on bifocals). Usually occurs on large frames, where the lab if not otherwise instructed, places the vertical center in the geometric center, and one discovers that the patient is looking through an area a good bit higher than this.
Somewhat related, many of us fail to realize that patients can tolerate very little vertical imbalance, we check for horizontal prism (We do always measure and check PD's.) but we don't realize that 1/2 diopter vertical is far too much. Even if there is no complaint, the patient will be fatigued.
Chip
I agree low ABBE, poor centration, and not compensated for position of wear, or frame set up are all making the spectacles more chalenging for the patient
This effect is produced because the Refaction Index of the lens is not the same of Hard coat.
It's the poly. Some people are sensitive to it? I get the same effect so do not wear it myself. It's not the AR. High polished edges will do it to.
Your optician used poly probably to enhance the sale and it is lighter, more scratch and impact resisitant, uv protection. If you don't want your opticians to sell certain materials in certain situations you have to tell them. Nine times out of ten the patient is happy with poly and percieves that it is a better lens.
Isn't the Ansi standard no more than 2/3?
My philosophy is, "Why not have the best vision possible?" Now, the patient's budget makes the final decision, but why sell poly when there's trivex and high index? Why have 2/3 vert. prism when you can have none?
More to the point of the thread, I agree...it's the poly. Rainbow is poly. AR brings other complaints, as does edge polish.
BINGO!!! You nailed it right on the head!
I find that very hard to believe, Optidonn...
If that were true, why have I NEVER had a complaint about 1.60 lenses? I sell high index far, far more frequently than I do poly. I sell poly only when I HAVE to, like for a kid (and even then I try to do trivex). However, I've seen many cases of polycarbonate causing a problem.
If the hard coat is causing a problem, why isn't this the case with CR-39, 1.60, 1.67, 1.71, 1.74?
Air gap........................Newton Rings
Also “Newton rings.” Concentric coloured rings which appear when two pieces of glass or clear plastic are pressed together. A problem with glass negative carriers and a phenomenon discovered by English physicist Sir Isaac Newton (1643-1727).
The rings appear when there’s a tiny air gap between two pieces of clear material. Light rays encounter destructive interference if the gap is of a certain size relative to the wavelength, resulting in the effect. It’s most pronounced if a convex lens is pressed up against a perfectly flat glass surface.
See at : http://photonotes.org/cgi-bin/entry.pl?id=Newtonsrings
I didn't read the whole post:hammer: CA could most likely be the problem but mixing indices of lens and coating WILL cause a rainbow/oil slick effect. You don't have to believe me just read Chris's post...it's a scientific FACT. Just look in any optics book.
Optidonn-
I guess my wording was a little off...the only part I was "finding hard to believe" was that the coating was causing the problem in this case.
I'm aware that it is a scientific fact, but my thinking is this:
If it doesn't cause problems (commonly) on lenses above and below the index given (poly), why would it cause a problem on poly?
How do you know what the index of a coating is?
I assumed that it does cause distortion but is the type of thing no one ever worries about. Kind of like how no one worries about the axis being one degree off on a quarter cyl.
Is this the type of distortion that is present but not noticable?
Yeah I'm getting in a bad habit of not FULLY reading posts. I get what you mean and your right.:D (I think I didn't really read the full post...I'm at work:cheers: )
I think you need to question the patient carefully and listen to his response. So many times we get patients who tell us they "see" things that annoy them, only to find out they're talking about something they see looking "AT THE LENS", not through the lens(as For-Life mentioned). If they're actually seeing colored fringes on objects when looking through the lenses(especially off center) then you know it's gotta be a C/A issue. Change to cr-39 or trivex to solve that problem. If the patient admits it's something he sees looking "at" the lens then It's probably the typical poly-v.s.-coating R.I. thing(FCL's post). You've gotta be sure what the patient's talking about before we start "solving" the problem.:) Chris..
Big fan of trivex. It's as safe as poly with better abbe. Index (1.53) is a little lower than poly thou.
Paul @ Silicon Valley California
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