offsetting "yellowing" vision from trivex

[ak47]

Patient has always worn uncoated cr39 clear lenses. We introduced prism and moved to trivex last time but did not like due to "yellowing" of vision. Now, patient only has one good eye and wants cr39 and does not want 3mm thick cr39. Is there a way (perhaps with a VERY slight tint) of removing this "yellowing" of trivex??

[drk]

Trivex itself is water-white. If anything, it has a slight bluish hue, if you ask me. Maybe that's what the dude is seeing, but I doubt it. Because if you tinted it blue, it would "block yellow" and it's already blue.

So the guy seems to be responding the the slight decrease in abbe value from 1.49 to 1.53. It's kinda freaky, but monocular patients are in a pickle.

If you are worried about liability (and that's not unreasonable AT ALL) tell the guy he's either going to have to deal with the trivex chromatic aberration or 3.0mm thick CR39 or you will just not make the job.

Even if you waiver the guy, that's no protection for you.

He has to compromise or find someone else that will.

[SergeTrigger]

Maybe you could try holding tint samples in front of the glasses while the patient is wearing them to see which color offsets the "yellow" properly then have them tinted that?

[drk]

Trivex itself is water-white. If anything, it has a slight bluish hue, if you ask me. Maybe that's what the dude is seeing, but I doubt it. Because if you tinted it blue, it would "block yellow" and it's already blue.

So the guy seems to be responding the the slight decrease in abbe value from 1.49 to 1.53. It's kinda freaky, but monocular patients are in a pickle.

If you are worried about liability (and that's not unreasonable AT ALL) tell the guy he's either going to have to deal with the trivex chromatic aberration or 3.0mm thick CR39 or you will just not make the job.

Even if you waiver the guy, that's no protection for you.

He has to compromise or find someone else that will.

[AndyOptom]

Patient has always worn uncoated cr39 clear lenses.

We introduced prism and moved to trivex last time but did not like due to "yellowing" of vision.

Now, patient only has one good eye and wants cr39 and does not want 3mm thick cr39.

Is there a way (perhaps with a VERY slight tint) of removing this "yellowing" of trivex??

My thoughts, roughy in order of your four sentences above:

I presume the Trivex is coated since you specify prior lens material and also lack of coating. Is the Trivex coating any kind of blue coating? Is the Trivex itself the original type or some kind of newer hybrid with additional in-mass HEV filtering? Both would add some (usually unnoticeable) yellowing to vision, old school Trivex is water white as drk has noted and AFAIK.

Prism was introduced, yet patient is apparently monocular. Why the prism in the absence of binocularity? Also, am wondering if what they could best describe as yellowing was actually related to dispersion (seems likely to me since monocular patients often have oblique habitual gaze).

If the problem is indeed low Abbe (which I frankly find unusual, it's that rare from what I've seen), again agreeing with drk they're stuck with thick CR39. Unless whatever IOT has cooked up recently with their Camber Pure series can help make polycarbonate behave more like CR39 in this respect.

Lastly, if you tinted the Trivex to offset any yellowing, I believe you'd at best render the view colour neutral yet dimmer across all visible wavelengths. Would the patient be able to tolerate that?

[SergeTrigger]

Maybe the patient is a mantis-shrimp capable of perceiving the UV spectrum and the yellowing they're noticing is from the UV blocking in the trivex