Results 1 to 24 of 24

Thread: 1.74 Like it?

  1. #1
    OptiBoardaholic
    Join Date
    Nov 2013
    Location
    Georgia
    Occupation
    Optical Retail
    Posts
    245

    1.74 Like it?

    Morning all!
    So I've been going over and retraining my self on lenses and materials, because I've come to realize that I was trained in a more bias way than I probably should have been.

    I've always hated 1.74 because of the abbe value and I've found that until super high RX's are hit it's not much thinner than 1.67. Am I on the mark in this or am I still nursing old ideas that are no good?

  2. #2
    Master OptiBoarder
    Join Date
    Dec 2013
    Location
    here
    Occupation
    Dispensing Optician
    Posts
    507
    It's another option in the arsenal of tools we have to choose from. I don't discount it (by that I mean disregard not reduce in price), but I agree that - depending on the RX and frame choice - it has some merit and virtues. I also agree that the thickness is similar to 1.67, again depending on the frame choice and RX. It also REQUIRES an anti reflective coating when ordered. I would love to see the lantal 1.9 but unfortunately it's unavailable in the US. Stoopid safety laws.... pffft whatever

  3. #3
    Eyes eastward... Uilleann's Avatar
    Join Date
    Jan 2007
    Location
    Utah
    Occupation
    Dispensing Optician
    Posts
    3,237
    Have done well with it for years and years. No issues whatsoever in 99% of cases. Have used it as low as -4's and -5's, and +3's and +4's on up. Much depends on pts expectations, insurance coverage (if any), frame selection and previous spec Hx. But as mentioned above, there is no reason not to keep it in the arsenal of products.

  4. #4
    Master OptiBoarder
    Join Date
    Aug 2008
    Location
    Seattle
    Occupation
    Dispensing Optician
    Posts
    1,019
    Quote Originally Posted by Boldt View Post
    Morning all!
    So I've been going over and retraining my self on lenses and materials, because I've come to realize that I was trained in a more bias way than I probably should have been.

    I've always hated 1.74 because of the abbe value and I've found that until super high RX's are hit it's not much thinner than 1.67. Am I on the mark in this or am I still nursing old ideas that are no good?
    Don't hate the material, hate the game. Hi-index 1.74 has a higher ABBE value than 1.67 and it is thinner, make a demo up for your patients as well as yourself.
    I didn't attend the funeral, but I sent a nice letter saying I approved of it. Mark Twain

  5. #5
    Bad address email on file
    Join Date
    Nov 2011
    Location
    New Zealand
    Occupation
    Dispensing Optician
    Posts
    79
    Quote Originally Posted by Paul Smith LDO View Post
    Don't hate the material, hate the game. Hi-index 1.74 has a higher ABBE value than 1.67 and it is thinner, make a demo up for your patients as well as yourself.
    Exactly right..

    I have two sets made up as 'demo' pairs. One set has -4.00 lenses on eye with 1.5 the other 1.67 another set has same rx but 1.5 and 1.74, then to make a point I have -8.00 in the same combo's one eye 1.5 the other 1.67 & 1.74 to show the difference.

    There is a marked difference in thickness on the 1.74 even on the -4.00 lens, but then as someone else mentioned it is down to frame selection and O.C's etc, some frames just end up looking bad no matter what index.

    I also have the equivalent but in + Rx's to show CT.

    Don't bother with astigmatic thickness on demo pairs as would have far to many demos to deal with. keep it basic, if you know the max edge thickness just apply that to whichever axis you are dealing with/want.

  6. #6
    Master OptiBoarder
    Join Date
    Oct 2005
    Location
    new york
    Occupation
    Optometrist
    Posts
    3,749
    I am wearing 1.74, transitions currently. My rx is about -4. It is noticeably thinner on the edges than the 1.67 I was wearing. I have the exact same rx In both pair and the eye size is larger in my 1.74s. I do notice what appears to be chromatic aberration when viewing blue or green displays, such as on a cable box, with my 1.74s. Even if I walk up close to a blue numerical display, it remains fuzzy. Everything else seems normal as far as I can tell.

  7. #7
    One eye sees, the other feels OptiBoard Silver Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    5,458
    Quote Originally Posted by Boldt View Post
    Morning all!
    So I've been going over and retraining my self on lenses and materials, because I've come to realize that I was trained in a more bias way than I probably should have been.

    I've always hated 1.74 because of the abbe value and I've found that until super high RX's are hit it's not much thinner than 1.67. Am I on the mark in this or am I still nursing old ideas that are no good?
    Boldt,

    I've experienced higher AR failure rates from multiple sources with 1.74. I think flexure may be the problem, easily solved by bumping the center thickness, which negates the refractive index advantage unless you're over -10 D or so. 1.70 has better optics but limited availability, and still some reliability problems.

    1.67 is tried and true, widely available, and is my choice if I must give thickness more consideration than optics. Otherwise it's Trivex and 1.60 all day long.

    Note to consumers- all of the lenses above weigh about the same.
    Last edited by Robert Martellaro; 12-21-2014 at 12:44 PM.
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



  8. #8
    OptiBoardaholic
    Join Date
    Nov 2013
    Location
    Georgia
    Occupation
    Optical Retail
    Posts
    245
    Chaoticneutral: 1.9 is nice I've seen it once and was shocked about it.

    I have some demos made up at a -6 sph in aspheric and non-aspheric. I see a small difference but, have always been under the impression that the abbe was the big thing. Though in a freeform sv would that make a big difference.
    Robert: Is it just a bonding problem to the 1.74, or is it it's so thin in flexes to much?

  9. #9
    Master OptiBoarder OptiBoard Gold Supporter
    Join Date
    Mar 2012
    Location
    Maryland
    Occupation
    Dispensing Optician
    Posts
    2,103
    I only use crizal Avance or sapphire on 1.74, and have it processed by a local essilor lab that can get the center thickness to 1.5. Never have problems with coating. I used to rarely use it because so many labs want the ct to be near 2.0, which negates any thinness that the higher index can achieve next to 1.67

    I only start to really think about it after -8, and don't jump to it quickly.

    1.74 Crizal avance and 1.74 Zeiss aspheric stock lenses are another matter, both come out incredibly thin and again no coating problems, at least for me. I think they can get the center thicknesses on the stock lenses MUCH thinner.

    Edit: SOMO 1.74 w/ Ultraclear AR FSV is an AMAZING value for a high myope with limited funds. Runs about the same price as Alize Airwear FSV. Good scratch resistance, Liveable cleanability. Cyl up to -4.00
    Last edited by Tallboy; 12-22-2014 at 11:25 AM.

  10. #10
    Master OptiBoarder
    Join Date
    Aug 2010
    Location
    Austin
    Occupation
    Optical Retail
    Posts
    585
    Its been a while since I looked into this so I'm not going to offer anything but an idea to research. If I recall, 1.74 lenses and their anti-reflective counter parts should receive an AR coat that is index matched to 1.74 for best results. The index matching process is probably going to see more rejections at the lab, which is what Robert may be referring to. http://www.2020mag.com/l-and-t/14169/

  11. #11
    One eye sees, the other feels OptiBoard Silver Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    5,458
    Quote Originally Posted by Boldt View Post
    Robert: Is it just a bonding problem to the 1.74, or is it it's so thin in flexes to much?
    It was adhesion-like problems initially, years ago, mostly with Zeiss, and the lab's (Soderberg/Walman) house coating. Lately it has been flexing at the center on minus, primarily when removing from zyl for frame realignments. It happened last week with an Avance -8.00 1.74, processed by Essilor. Curiously, the other eye, a -12.00, survived the experience.

    Quote Originally Posted by AustinEyewear View Post
    Its been a while since I looked into this so I'm not going to offer anything but an idea to research. If I recall, 1.74 lenses and their anti-reflective counter parts should receive an AR coat that is index matched to 1.74 for best results. The index matching process is probably going to see more rejections at the lab, which is what Robert may be referring to. http://www.2020mag.com/l-and-t/14169/
    Index matching the hard coat is really more of a cosmetic concern, primarily Newton Rings I think. My 1.74 failures look like vertical wrinkles which come and go depending on stress when mounted or dismounted, primarily with thick zyl frames.
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



  12. #12
    Master OptiBoarder AngeHamm's Avatar
    Join Date
    Apr 2010
    Location
    Richmond, VA
    Occupation
    Optical Retail
    Posts
    2,369
    Quote Originally Posted by Tallboy View Post
    I only use crizal Avance or sapphire on 1.74, and have it processed by a local essilor lab that can get the center thickness to 1.5. Never have problems with coating. I used to rarely use it because so many labs want the ct to be near 2.0, which negates any thinness that the higher index can achieve next to 1.67

    I only start to really think about it after -8, and don't jump to it quickly.

    1.74 Crizal avance and 1.74 Zeiss aspheric stock lenses are another matter, both come out incredibly thin and again no coating problems, at least for me. I think they can get the center thicknesses on the stock lenses MUCH thinner.
    +1. Exactly my experience. I'm wearing 1.74 clear with Sapphire right now; lovely lenses in my -10s.
    I'm Andrew Hamm and I approve this message.

  13. #13
    Bad address email on file
    Join Date
    Dec 2013
    Location
    Bristol
    Occupation
    Dispensing Optician
    Posts
    268
    I have similar prejudice about the 1.74, so I'm commenting to keep track of this thread.

    For those of you talking about 1.9 - it's not the Holy Grail by any stretch. Problem is, I only ever get to use it with horribly myopic patients, and the lenses are always thick - a small part of your brain expects it to be as thin as a -2.00 or something. The last one I dispensed was -14.00D (ish). It was lovely and thin (considering the rx), but still super thick.

  14. #14
    Master OptiBoarder
    Join Date
    Jun 2008
    Location
    Seattle WA
    Occupation
    Optical Wholesale Lab (other positions)
    Posts
    3,137
    The AR issue with 1.74 is that it should be dipped hard coated, and not spin coated. No one makes a specific spin coat for 1.74... and with only 2 players in the US (patent issues) there is little motive to do so.

  15. #15
    Master OptiBoarder
    Join Date
    Jun 2008
    Location
    Seattle WA
    Occupation
    Optical Wholesale Lab (other positions)
    Posts
    3,137
    but in general, here many practices are selling more 1.74 than 1.67 due to the higher ABBE value...

    But having cut a few in half, it is noticeably thinner in minus powers than 1.67 is.

  16. #16
    Bad address email on file
    Join Date
    Dec 2013
    Location
    Bristol
    Occupation
    Dispensing Optician
    Posts
    268
    Quote Originally Posted by sharpstick777 View Post
    but in general, here many practices are selling more 1.74 than 1.67 due to the higher ABBE value...

    But having cut a few in half, it is noticeably thinner in minus powers than 1.67 is.
    Having given the data to my patients using various different tracer/software combinations - they don't agree at all. Say we're looking at the common 'higher' rxs (-6.00D, -7.00D ish), then the saving isn't normally more than half a mm with a well chosen frame.

    Are you thinking of much higher rxs than that? I guess I just don't see that many really strong prescriptions.

  17. #17
    Master OptiBoarder
    Join Date
    Feb 2008
    Location
    Jacksonville, Florida
    Occupation
    Optical Laboratory Technician
    Posts
    1,012
    YMMV but I really like what the material does for plus power lenses. Did a pair of +6.00 in a 54 eye with no protrusion outside the eyewire at the nasal, the pat. was impressed.
    Clinton Tower

    The intellect to live free is in short supply
    ALT248=°

  18. #18
    Master OptiBoarder AngeHamm's Avatar
    Join Date
    Apr 2010
    Location
    Richmond, VA
    Occupation
    Optical Retail
    Posts
    2,369
    Quote Originally Posted by scriptfiller View Post
    YMMV but I really like what the material does for plus power lenses. Did a pair of +6.00 in a 54 eye with no protrusion outside the eyewire at the nasal, the pat. was impressed.
    It's gorgeous with high pluses. But again, frame selection is even more important.
    I'm Andrew Hamm and I approve this message.

  19. #19
    Bad address email on file
    Join Date
    Dec 2013
    Location
    Bristol
    Occupation
    Dispensing Optician
    Posts
    268
    Quote Originally Posted by scriptfiller View Post
    YMMV but I really like what the material does for plus power lenses. Did a pair of +6.00 in a 54 eye with no protrusion outside the eyewire at the nasal, the pat. was impressed.
    Plus lenses, I'm in full agreement with. AngeHamm is spot on with the importance of frame selection. With the right frame, we can make almost any rx look good. High index following a good frame choice is icing on the cake.

  20. #20
    Master OptiBoarder
    Join Date
    Oct 2005
    Location
    new york
    Occupation
    Optometrist
    Posts
    3,749
    Really important to keep those high pluses near round with minimal decentration...but everybody knows that.

  21. #21
    OptiBoard Professional
    Join Date
    Dec 2005
    Location
    Middle America
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    124

    1.74 alternative

    Vision-Ease often seems to be a second-thought from Optiboarders, but an excellent alternative to 1.74 is their Thindex 1.70. It has a higher ABBE than 1.67 or 1.74, similar thinness profile to 1.74, high surface tensile strength for successful drilling, and available in semi-finished for surfacing to power (both spherical in clear and Transitions Signature VII for freeform, and aspheric clear) and finished single vision aspheric with AR. Also priced between the two.

    You can view specs here: http://www.vision-ease.com/Portals/V...ctSpecs114.pdf

  22. #22
    Master OptiBoarder OptiBoard Gold Supporter
    Join Date
    Mar 2012
    Location
    Maryland
    Occupation
    Dispensing Optician
    Posts
    2,103
    1.70 is great, but the AR choices arent as solid unfortumately though. I notice the cleanability of my 1.70 to be way less than my avance 1.67.
    . but the peripheral clarity of the 1.70 is noticeably better

  23. #23
    One eye sees, the other feels OptiBoard Silver Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    5,458
    Quote Originally Posted by OIC View Post
    Vision-Ease often seems to be a second-thought from Optiboarders, but an excellent alternative to 1.74 is their Thindex 1.70. It has a higher ABBE than 1.67 or 1.74, similar thinness profile to 1.74, high surface tensile strength for successful drilling, and available in semi-finished for surfacing to power (both spherical in clear and Transitions Signature VII for freeform, and aspheric clear) and finished single vision aspheric with AR. Also priced between the two.

    You can view specs here: http://www.vision-ease.com/Portals/V...ctSpecs114.pdf
    Look at all of those BCs! What's with the redundancy on the flatter curves?

    Quote Originally Posted by Tallboy View Post
    1.70 is great, but the AR choices arent as solid unfortumately though. I notice the cleanability of my 1.70 to be way less than my avance 1.67.
    . but the peripheral clarity of the 1.70 is noticeably better
    You must have a fairly strong Rx. I'm sensitive to chromatism also with my moderate myopic Rx. I wish Zeiss would/could embrace 1.70/1.71 for their super high index material of choice.
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



  24. #24
    Master OptiBoarder OptiBoard Gold Supporter
    Join Date
    Mar 2012
    Location
    Maryland
    Occupation
    Dispensing Optician
    Posts
    2,103
    I'm a -6.00 with -0.75 cyl in my worst eye. I can wear poly or 1.67, but I notice purplish lights disperse more on the edges of my lower abbe lenses. The drive Gear shift labels in my car glow blue and when I look at them out of the periphery of my lenses i see two Ds split. My 1.70s dont do this. It was weird when I noticed it. It has happened in a few other instances also. I still will wear poly though

Thread Information

Users Browsing this Thread

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

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
  •