Chromatic aberration (consumer)

[David C]

I recently ordered a pair of glasses (-2.00) with polycarbonate lenses and sent them back because chromatic aberration was causing red and blue fringes on high-contrast edges and in general everything looked less than clear, even if I couldn't discern the colored fringes. Kind of like a bad color print or a misconverging color monitor. So I sent them back and they redid them in high-index plastic (1.67, I think), and I found the problem to be as bad or worse. The people I was dealing with didn't appear to understand my complaint (they suggested trying polycarbonate again) and said that it was not a common one among their patients.

Today I went to another optician and was told that if I could see chromatic aberration through high-index plastic, I was unusually sensitive. I find that hard to believe and asked whether it could be due to poor craftsmanship instead, and they said no. They also guessed that my current glasses (-1.00) are polycarbonate, and I have no problem with chromatic aberration. (Now that I am aware of it, I can see it very slightly at the very edges, but it's completely not a problem.)

So, I'm puzzled about why both pairs of new glasses were so bad for me and whether I can trust the same optician to make CR39 lenses for me, or should I go somewhere else?

Thanks in advance!

David

[chip anderson]

It's your problem and your decision. You could even concider glass with a low precription like this.

Chip

[Pete Hanlin]

If you can discern color fringing with a -2.00 polycarbonate lens, it would seem you are- indeed- rather sensitive to chromatic aberration (I used to wear poly lenses with a power of -4.75, and could only sporadically sense minimal chromatic effects). However, the fact that you continued to notice the fringes while wearing high index lenses is not surprising and would seem to bear out that you are actually noticing chromatic aberration. 1.67 lenses have approximately the same abbe value (i.e., tendency to break light into colors) as polycarbonate.

Chromatic aberration occurs as a result of prism, and your -2.00 lenses create more peripheral prism than your former Rx, which would explain the fact that you have not noticed the fringing in the past.

Return to the optician, and insist on CR-39 lenses. Unless you are wearing exceptionally large frames, I cannot imagine thickness will be an issue. The abbe value of CR-39 is roughly twice that of poly and high index lenses. If you notice chromatic aberration in CR-39 you should 1.) apply for work as some sort of visual inspector, and 2.) consider contact lenses, which will not cause the effect you are noticing in your spectacles.

Good luck,
Pete

[David C]

Thanks very much for your quick replies! The people I have been dealing with (Kaiser Permanente) have been kind enough to replace my lenses once and are prepared to replace them a second time, but maybe not the third time (I'm not sure). But if I understand you correctly, I should not be worried about getting a bad pair of CR39 lenses from them?

Since the consensus seems to be that I'm the aberration :P maybe I can ask a completely tangential question which may or may not be appropriate for this forum. I work on a computer all day and I find that unlike most people, I get more eyestrain from LCD monitors than CRT monitors, provided the CRT's refresh rate is above 75 Hz or so. (The exception was my old PowerBook's LCD, which I never had any problem with...maybe it was dimmer.) I especially can't look at sharp black text against a white background; antialiasing (which uses gray pixels to increase effective resolution at the expense of sharpness) is much easier to look at, although subpixel addressing (which manipulates the individual red, green, and blue elements of an LCD to increase the actual resolution) is often not desirable because of...colored fringes.

So, now I'm wondering what, physiologically, is different about a person that would make him/her more sensitive to chromatic aberration, and whether that would also explain why I get eyestrain in situations where other people don't. Or am I just crazy :)

Thanks again!

David

[Jim Stone]

So, now I'm wondering what, physiologically, is different about a person that would make him/her more sensitive to chromatic aberration, and whether that would also explain why I get eyestrain in situations where other people don't. Or am I just crazy :)

Thanks again!

David

"physiologically" close but more,"am I just crazy ". It is actually really nice to be able to say this. Sorry Dave, but this is probly the case. Try some A/R though. Just might be help enough for you to get through your problem.

[Barry Santini]

unless the base curve; face-form, panto and vertex distance of the dispensed eyewear is evealuated, I think to conclude you have "color-fringe"/abberation-sensitivity is too long a leap.

Barry Santini, ABOM

[Chris Ryser]

I
So, I'm puzzled about why both pairs of new glasses were so bad for me and whether I can trust the same optician to make CR39 lenses for me, or should I go somewhere else?

For your Rx which is a not a complicated job, actually one the simplest jobs in the optical wearing high index in either Poly or other is pushing the buck to far.

Whatever optician sold you either one, should be ashamed and banned from selling glasses...........he is full of greed and has NO ethics. Poly and other high index have lower base curves and give you a different feel of vision.

Just get a pair of lenses and mention that they give and charge you for stock lenses in regular CR39 which the closest to glass in the way of visual results and forget the high index you dont even need.

[Jim Stone]

Whatever optician sold you either one, should be ashamed and banned from selling glasses...........he is full of greed and has NO ethics.

Dang dude! There are people on this optiboard that are expected to automatically sell "the package". If they don't so many they lose thier jobs. (It was not the ignorant street people trainees that came up with these policies.) Also this fellow probly came in and ask for thin lenses. Now, with your advice, he's going to go to the local authorities to close this place down! Maybe print this thread out and file a malpractice claim. WOW!

[Fezz]

1.) A nice pair of glass lenses. Nice and clear with a Anti-Reflective coating
2.) A nice pair of CR-39/plastic lenses with a A-R coating
3.) A nice pair of Phoenix/Trivex lenses with A-R coating


Good Luck.


Fezz
:cheers:

[David C]

Try some A/R though.

Yes, both pairs already had the A/R coating, don't know what kind.

Also this fellow probly came in and ask for thin lenses.

No sir, I did not.

Thanks again for your replies all!

David

[AWTECH]

recently ordered a pair of glasses (-2.00) with polycarbonate lenses and sent them back because chromatic aberration was causing red and blue fringes on high-contrast edges and in general everything looked less than clear, even if I couldn't discern the colored fringes.

You state that you have identified the problem as chromatic aberration. I would like to know how you came to this conclusion. The fact that you can see red and blue in the fringes of the lens could also be due to the mismatched index of the lens and the hard coating used. Since most opticians have no conclusive way to identify cromatic abberation problems and I doubt that many consumers do either, I would not pass judgement so quickly as to identifying your problem as chromatic abberation. The index of polycarbonate is 1.58 and most hard coatings are 1.50 to 1.52. With poly there is also a primer used which is also a 1.50 index. Depending on hard coating and primer thickness this maybe causing some very slight chomatic fringe issue. This would not cause everything to look less clear.

It could even be reflections in the fringes of the lens from the frame depending on the frame material and color.

If you put a non coated CR-39 lens in the same frame and can see perfectly then you would know that the frame was not a factor.

The lack of lens clairity is not a part of chromatic abberation. It sounds to me like there is probably another issue and the chromatic abberation was a guess based on no factual analysis.

There are so many possiblities that I skilled optician should be able to go through the process of elemination and determine a solution. (The Rx could even be wrong for example).

[David C]

You state that you have identified the problem as chromatic aberration. I would like to know how you came to this conclusion.

Nope, I don't know for sure. It sounds like I may have used an overspecific term to describe what I was seeing. All I know is that if, for example, I looked at a white object against a black background, then the left edge would appear red and the right edge would appear blue, if I looked at it to one side, and the colors would reverse if I looked at it to the other side. To a much lesser extent, the same would happen if I looked at it above or below. If I looked at it dead-center, I didn't see anything, but it often didn't have to be that far off-center (hard to estimate -- 15 degrees?) to become noticable. I wish that my optician would try to determine the problem in the way that you describe, but that doesn't really seem to be happening.

[j.west]

david, i have the same experience, pretty much. i don't think insanity is the cause, but rather the result.

i believe i raised the lcd issue before ... in similar detail...but got little or no response.

thanks pete, for suggesting '' a book written by a Dr. Sheedy on the subject entitled: Diagnosing and Treating Computer-Related Vision Problems.'' should be interesting read.

[David C]

So, I got the new glasses from a different place (CR39 with Crizal Alize) and...I DO still see the colored fringes. It's definitely much better than before, probably about half as much fringing or less. Also the general bad-color-print feeling is gone and everything looks much more clear and pleasant (this could be because of the better AR coating too, right?). But, I still do see the fringes. The optician suggested I get my eyes checked by an ophthalmologist!

Thanks very much for your help everyone.

David

[Uncle Fester]

Old Thread alert- (Maybe headed for HoF?)

Patient sees blue around objects. Especially in distance. I cannot see the effect.

R +.75 -.50 x75
L +.50 -.50 x110
Add +2.25

Comfort DRX Poly no AR
Prism thinning 1.15
Base Curve +4.25


First progressive. No issue with previous FT28 no AR.

Will try to adjust panto and wrap first.
Plan B redo cr-39 no prism thinning.

Other suggestions? Change BC?

[Uilleann]

Old Thread alert- (Maybe headed for HoF?)

Patient sees blue around objects. Especially in distance. I cannot see the effect.

R +.75 -.50 x75
L +.50 -.50 x110
Add +2.25

Comfort DRX Poly no AR
Prism thinning 1.15
Base Curve +4.25


First progressive. No issue with previous FT28 no AR.

Will try to adjust panto and wrap first.
Plan B redo cr-39 no prism thinning.

Other suggestions? Change BC?

Basic physics/optics tells us that with that low a power (assuming a perfect fit - which of course you would have already made Fester), that the level of CA the human eye might perceive is below subjective detection. Cataracts a factor at all? Some other retinopathy? Did the new SRx clear things up enough that the pt is now seeing something that's always been there? - Just thinking out loud...

[Uncle Fester]

It's a real head scratcher to me as well. I've always been able to see this when it presented in the past ergo I'm asking youz guyz!

[Uilleann]

It's a real head scratcher to me as well. I've always been able to see this when it presented in the past ergo I'm asking youz guyz!

I wish Fezz was still around - he could tell us if the pt's visual disturbances at distance might simply be related to ingestion of the wrong type of IPA or lager...or if it was just plain ol optics. Hehehe