Page 2 of 2 FirstFirst 12
Results 26 to 42 of 42

Thread: Chromatic aberration (consumer)

  1. #26
    Master OptiBoarder
    Join Date
    Oct 2005
    Location
    new york
    Occupation
    Optometrist
    Posts
    3,749
    David, I hope you don't mind me asking a related question here about poly lenses...but does any eyewear professional here have actual experience with whether a RESOLUTION poly lens is any better than standard poly in regard to patient symptoms of chromatic abberation?

  2. #27
    Bad address email on file
    Join Date
    Jul 2006
    Location
    Los Angeles, CA
    Posts
    10
    What I originally ordered was a pair of glasses, without specifying a material since I didn't know anything about them. I think it's fine that they gave me polycarbonate; I don't think it's fine to see colored fringes but I'm still unclear about why that happened.

    For the second pair I was not charged extra for the high-index plastic. The optician that was helping me thought they were doing me a favor by upgrading me for free. I don't think they had any familiarity with this problem of color fringing whatsoever.

  3. #28
    One of the worst people here
    Join Date
    Jan 2004
    Location
    Canada
    Occupation
    Other Eyecare-Related Field
    Posts
    8,331
    Quote Originally Posted by mike.elmes
    Recently I updated my stock lenses to include Airwear Alize, in the powers +/- 3 and up. This was done to enable us to offer thinner lenses and so we could accomodate the silhouette's, and other drill mounts. I have had some negative feedback regarding chromatic abberation from a few of my customers. We do reccomend airwear in any drill mount as breakeage is MUCH less. However, their are issues. Edge polish is highly reccomended for this material, but is somewhat annoying in terms of adding reflections. Some customers love the weight and don't seem to have a problem with the chromatic abberations, or edge polish. Others are highly annoyed.
    What alteratives exist for drill mounts that have low chr. abbe? Is the Trivex material all it's cracked up to so to speak?
    Trivex is thicker. If you are talking plano to -3.00 then trivex is a nice material. However, you recently updated your stock with Airwear Alize. You cannot do that with Trivex. There is not a stock lens of trivex available with a coating like Alize. The only Alize like coating available for Trivex is Super Hi Vision, and for that the lens needs to be surfaced. So now it is costing you twice, to three times more to stock each lenses.

    1.6 and 1.67 are also good lenses for drill mounting.

  4. #29
    sub specie aeternitatis Pete Hanlin's Avatar
    Join Date
    May 2000
    Location
    Hickory Creek, TX
    Occupation
    Lens Manufacturer
    Posts
    4,947
    What I originally ordered was a pair of glasses, without specifying a material since I didn't know anything about them. I think it's fine that they gave me polycarbonate; I don't think it's fine to see colored fringes but I'm still unclear about why that happened.

    Regarding the mechanics of chromatic aberration (or the colored fringes)...

    All lens materials effectively slow down the speed of light (i.e., light traveling through a lens material travels slower than it does when traveling through a vacuum/air).

    When light strikes a lens surface at any angle other than perpendicular, its course is altered. Sunlight (white light) is composed of all the colors- since each color has its own wavelength, the different colors are refracted unevenly. This is why a prism breaks light down into colors (its also the reason for rainbows). All lenses (those with refractive power, anyway) are basically composed of prisms. The higher the refractive ability (index of refraction) of the lens, the more it tends to break light into colors (polycarbonate has a tendancy that is slightly disproportionate to its refractive index).

    There is usually no prismatic power in the center of the lens (which is why you don't notice the color fringing in the middle of the lens). As you go towards the periphery of the lens, you will encounter stronger and stronger levels of prism (also, the more refractive power the lens has, the more prismatic power will be present).

    For the second pair I was not charged extra for the high-index plastic. The optician that was helping me thought they were doing me a favor by upgrading me for free. I don't think they had any familiarity with this problem of color fringing whatsoever.
    There are two possible reasons for your optician's non-familiarity with chromatic aberration. The first of which has already been suggested (namely, sensitivity to chromatic aberration is fairly rare). The second is, the majority of opticians have formal training in the field of ophthalmics. In fact, the majority of states have no minimal requirements for individuals who fit and dispense ophthalmic equipment.
    Pete Hanlin, ABOM
    Sr. Director Professional Solutions
    Essilor of America

    http://linkedin.com/in/pete-hanlin-72a3a74

  5. #30
    OptiBoard Professional Mike Fretto's Avatar
    Join Date
    Jun 2000
    Location
    Shelby, North Carolina, USA
    Occupation
    Dispensing Optician
    Posts
    232
    I scanned most of the responses and didnt see any mention of face form adjustment. I may have overlooked one but wouldnt this be a possible solution to his problem.
    Mike

  6. #31
    Bad address email on file
    Join Date
    Jul 2006
    Location
    Los Angeles, CA
    Posts
    10
    Quote Originally Posted by Pete Hanlin
    The higher the refractive ability (index of refraction) of the lens, the more it tends to break light into colors (polycarbonate has a tendancy that is slightly disproportionate to its refractive index).
    Thanks for this explanation -- would the amount of fringing be proportional to the strength of the lens? I.e., should one expect to see twice as much fringing through a -2.0 lens than through a -1.0 lens, or does it not work like that for some optical or perceptual reason?

  7. #32
    Forever Liz's Dad Steve Machol's Avatar
    Join Date
    Apr 2000
    Location
    Back in AZ
    Occupation
    Other Eyecare-Related Field
    Posts
    9,508
    Yes, it's a function of both lenses power (or more correctly 'prism' which is higher off-center on higher powered lenses) and the refractive index of the materials.


    OptiBoard Administrator
    ----
    OptiBoard has been proudly serving the Eyecare Community since 1995.

  8. #33
    Bad address email on file
    Join Date
    Jul 2006
    Location
    Los Angeles, CA
    Posts
    10
    Quote Originally Posted by Steve Machol
    Yes, it's a function of both lenses power (or more correctly 'prism' which is higher off-center on higher powered lenses) and the refractive index of the materials.
    Is it a linear function of both? What I observed was the fringing was like 10 times worse (just my guess) through -2.0 lenses than through -1.0 lenses -- does that suggest that some other variable is interfering? Thanks!

  9. #34
    sub specie aeternitatis Pete Hanlin's Avatar
    Join Date
    May 2000
    Location
    Hickory Creek, TX
    Occupation
    Lens Manufacturer
    Posts
    4,947
    Given the same material (and assuming you look through the exact same spot relative to the optical centers of both lenses), a -2.00 lens should produce twice as much chromatic aberration as a -1.00 lens.

    From what you have stated, it seems as though the increase you've noticed appears to be almost exponential rather than linear. This could be due to some thresh hold you have for chromatic aberration- that is, perhaps x amount doesn't bother you, but 1.5x is quite noticeable...

    Interestingly enough, but doubling the abbe value of the material (which is approximately what you will be doing by switching from polycarbonate to CR-39), you will more or less exactly compensate for the 2x increase in power (from -1.00 to -2.00). Therefore (again, assuming you look through the same spot relative to the optic centers), you should notice about the same amount of chromatic aberration in your -2.00 CR-39 as you did in your -1.00 polycarbonate lenses.

    Let us know when you receive your new lenses- I'm sure several of us are now quite curious to "see" how this all turns out (pun intended).
    :)
    Pete Hanlin, ABOM
    Sr. Director Professional Solutions
    Essilor of America

    http://linkedin.com/in/pete-hanlin-72a3a74

  10. #35
    OptiBoard Apprentice
    Join Date
    Jul 2004
    Location
    Detroit, Michigan
    Occupation
    Other Eyecare-Related Field
    Posts
    39
    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.

  11. #36
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    5,778
    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

  12. #37
    Bad address email on file
    Join Date
    Jul 2006
    Location
    Los Angeles, CA
    Posts
    10
    Quote Originally Posted by Pete Hanlin
    Let us know when you receive your new lenses- I'm sure several of us are now quite curious to "see" how this all turns out (pun intended).
    :)
    Thanks, I actually switched from Kaiser to a independent optometrist/optician's office and they were much more helpful.

    Quote Originally Posted by B. 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.
    I don't understand what you just said :) but I gathered from quite a few posts here that there are lots of variables involved, so I took a chance and changed both the frame and the material (and the lab), so we'll see how it goes. Thanks.

    David

  13. #38
    Bad address email on file
    Join Date
    Jul 2006
    Location
    Los Angeles, CA
    Posts
    10
    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

  14. #39
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
    Join Date
    Dec 2004
    Location
    At a position without dimension...
    Occupation
    Dispensing Optician
    Posts
    4,405
    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?

  15. #40
    Eyes eastward... Uilleann's Avatar
    Join Date
    Jan 2007
    Location
    Utah
    Occupation
    Dispensing Optician
    Posts
    2,756
    Quote Originally Posted by Uncle Fester View Post
    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...

  16. #41
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
    Join Date
    Dec 2004
    Location
    At a position without dimension...
    Occupation
    Dispensing Optician
    Posts
    4,405
    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!

  17. #42
    Eyes eastward... Uilleann's Avatar
    Join Date
    Jan 2007
    Location
    Utah
    Occupation
    Dispensing Optician
    Posts
    2,756
    Quote Originally Posted by Uncle Fester View Post
    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

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Pt wears Poly w/ no aberration, Hi-index drives her crazy!
    By ilanh in forum General Optics and Eyecare Discussion Forum
    Replies: 22
    Last Post: 02-17-2008, 10:34 AM
  2. abbe values and chromatic aberration
    By mirage2k2 in forum Ophthalmic Optics
    Replies: 18
    Last Post: 03-24-2006, 11:45 AM
  3. Chromatic aberration & depth perception
    By russell in forum Ophthalmic Optics
    Replies: 15
    Last Post: 09-07-2005, 02:03 PM
  4. high abbe value glasses lenses
    By chris.pickett in forum Ophthalmic Optics
    Replies: 11
    Last Post: 08-08-2005, 02:49 PM
  5. More on Chromatic Aberration and Poly
    By Alan W in forum General Optics and Eyecare Discussion Forum
    Replies: 2
    Last Post: 04-13-2001, 08:22 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
OptiBoard is proudly sponsored by:
Younger Optics and Vision Equipment