Compensated RX for Optimized Lenses….?

[eyecarepro]

I have a patient with the following RX:

-4.50 Sph
-4.50 -0.50 X005
+2.25 Add

fit with 1.67 Trans Xtra Active PAL lens: Ideal ADV IV Fit

the glasses came back from the lab with a compensated RX of:

-4.27 +0.72 X146
-3.84 -0.64 X142
+2.17 Add

based on digital measurements taken, the lab optimized the RX by using the panto and pano angles, and vertex distance. The eyeglasses definitely read what the optimized RX is but the optimized RX is just so different from the prescribed RX it’s just hard to believe that this RX would pass final inspection. It almost feels like a sneaky way of passing an RX at the lab that didn’t quite come out on power but that also feels like a reach. Optimized Lenses and Compensated RX’s are still a bit of a grey area for me as I work in a heavily retail based environment and less optical. Does this amount of variance between actual prescribed RX and the optimized lenses seem right, to those that work with digital lenses and optimized lenses on a regular basis? Not all of our lenses are HD/Digitally Surfaced so not all of our jobs come in with a compensated RX supplemental form to cross reference against the prescribed RX. My colleagues have failed this job twice now so I figured I’d reach out to my fellow opticians for some guidance on the matter, TIA!

[mervinek]

I've had that happen when the compensated Rx was quite different from the prescribed rx. I know that those numbers from my lab are computed by the program and not just typed in by an employee so I didn't feel like they were sneaking one past me. In that case I just called the lab to discuss the numbers. I don't remember what the result was but all was well in the end. I would suggest you just give them a call (if you have a good trustworthy lab). Maybe call to verify the POV measurements that you gave to the lab?

[Uncle Fester]

Robert Martellaro once put it best:

"Who understands differential geometry?"

Take a dive if you dare into this deep rabbit hole-

https://www.google.com/search?client...ntial+geometry

[NAICITPO]

Robert Martellaro, what a brilliant quote! Lol no thanks Fester, I'll trust the computers and see how the patient reacts.

Eyecarepro I would call the lab like mervinek said and ask to talk to their head optician if you are really concerned with how the rx turned out. But I think if you keep on getting the same compensated Rx back twice I wouldn't remake it a third time hoping for something different, that's insanity, just let the patient try the Rx.

[Uncle Fester]

I have gotten slightly different numbers using the same POW measurements so I trust what was sent.

I remember this issue being discussed some time ago and believe the reason why same rx numbers varied was the formulas are constantly being tweaked however that raised my eyebrows when the rx was ordered at the same time.

Someone may want to verify this but I believe branded compensated lenses charge a click fee every time an rx is entered so you cost the lab money if you want to verify an rx and have not even tried the lenses on the patient first.

But I have many times found patients get so used to an old design that changing them is sometimes not going to work. (It's 85% the proper frame selection and fit by the optician that determines success imo.)

I explain a redo back to their old design by telling the patient in a light hearted manor "You are seeing better according to Shamir. So are you going the believe the optical engineer who designed this lens or your own darn eyes?!"

It makes the loss off the couple hundred dollars extra for the upgrade easier to swallow.

[eyecarepro]

Thanks for the advice folks. That’s what we decided, let the patient try the eyeglasses and let HER make the judgement call based on her visual acuity with the eyeglasses. Maybe I take my job as a Licensed/ABO Certified Optician a teensy-weensy bit too seriously at times, lol.

[NAICITPO]

Good deal! Yeah, we aren't prescribing drugs here, even though we are filling an Rx. People get an "objective" refraction, but is it really objective for all people? I've seen on multiple occasions 2 doctors both of whom I respect as refractionists come up with 2 different Rx's for the same person within a couple weeks time. The ultimate decider is what the customer feels when wearing them. If you can get that "wow" from the customer that's what matters the most for me (not saying throw tolerances out the window).

[Lensman11]

There is a face wrap and panto calculator as part of the opticampus section on this web site. Put in your numbers you should get a reasonably close answer to your question. Vertex distance is not used in this case so the results will vary slightly.

[Robert Martellaro]

The differential geometry quote I probably swiped from Darryl M., as I typically only steal from the best.

ECP,

There's a typo on the compensated right cylinder sign.

That is a lot of cylinder for that power but would certainly be normal with significant (12+ degrees) tilt around both the horizontal and vertical meridians, although with wrap we should see a small amount of BI prism.

Best regards,

Robert Martellaro

[drk]

I'd give my left nut to be able to post with Darryl Meister.

[Robert Martellaro]

Sigh.

[Prentice Pro 9000]

Why the heck does the Rx have unmatching cylinder forms?

[Uncle Fester]

Why the heck does the Rx have unmatching cylinder forms?

Thick fingers is my guess;)

Had an optic theory teacher who would look over our shoulders when when taking a test doing a Gauss equation through 5 or 6 mediums. He'd point to one of your early calculations and say "Oh-- too bad. Thick fingers." at an earlier entry and you knew from then on all was lost so it was back to fix it from there. Ughh...

We went out to the 5th decimal point using our spiffy new Texas Instrument hand calculators in 1975.