The smoke continues to flow from my ears and obscures the room.
Can you dumb this down for the mathematically challenged?
The smoke continues to flow from my ears and obscures the room.
Can you dumb this down for the mathematically challenged?
In order for a lens to be free from astigmatic blur at all gaze angles light should come to a point focus on the far point sphere(center of rotation - focal length of the lens). This imaginary sphere is used as a reference point. If light focuses behind or in front of the sphere the lens will not be clear. You may have experienced this when a wearer looks in the periphery and states it is not as clear as it is in the center.
Dr Marius Tscherning discovered that two forms exist where a lens will be free from astigmatism(each one of these forms had been previously discovered independently by Ostwalt and Wallaston). For example a -5.00 that is 2 mm thick with a 27 mm center of rotation in CR-39 should be placed on either a 16.73 D BC or a 4.64 D BC. If you change the power to -4.75, this changes the two base curves to 16.84 D and 4.78 D. Based on Tscherning's work the ZIESS Punktal and AO's Tillyer lens were created.
Corrected curve theory is based on Tscherning's ellipse. Corrected curve theory groups powers that will have a certain amount of astigmatism in a series of base curves.
As our focus changes the far point sphere becomes the near point sphere, which will require a new form to be free from astigmatism.
FFSV lenses corrects the astigmatism for each gaze angle in the distance portion, however, in the past they did not correct the astigmatism produced at near.
I hope this helps.
*edit*
nevermind, question answered. Please delete
Last edited by Lawman Nick; 06-22-2020 at 03:16 PM. Reason: I'm a big ol' bonehead
Thanks- this did help with a second closer reading of drk's always erudite posts.
If this came to me easily I very much doubt I would be an optician.
I still get nervous selling something that seems to fix for most what isn't broken. or seemingly they didn't know it was broken until I'm selling it.
Too often I fear the what if- such as when a patient gets switched to the latest and greatest and expects immediate results only to return later asking for a redo (and worse, refund) for the more expensive lenses.
So I often qualify the change with a proverbial "your results may vary".
With the right patient who doesn't like the change I've even lightened the mood with a "Who are you going to believe? The optical engineers or your own d*amn eyes!"
OK, I'm learning.
The most basic model of Zeiss' new "Lite" basic model series has a 14 and 18mm variation.
14 is corridor length, I think. Ergo, for a minimum recommended fitting height for this variation, add, what? 4-5 mm? So, it's good for 18-19 mm fitting heights?
Or is 14 the minimum recommended fitting height, itself?
Same with 18. It could be for 22-23 mm fitting heights, or it could be the minimum recommended fitting height.
I need some smart dude to set me straight.
I've always added 4 to the minimum fitting height so people dont complain about the near zone being too low.
The Zeiss Lite lenses come in three flavors.
The D is the lowest tier with 14,18 corridors and "optimized boundaries for widest fields of view"
The H comes in 14, 16, and 18 with optimized boundaries and "binocular optimization"
The V is a variable corridor for customized fitting heights as low as 13mm.
The intermediate and Near Zones are supposed to be a few mm wider than average but the distance zone seems pretty narrow with a good amount of distortion in the periphery. I'm not sure if thats due to "Binocular optimization" or not trying to put all the bells and whistles in a lower priced lens.
Now Zeiss has the Smartlife "Pure" in Small, Medium, and Large to replace the Precision Pure. I have no idea what lengths Small, Medium and Large refer to and the only thing the lab could tell me was that its the same as the Precision Pure which comes in 13, 15, 17, 19, 21 lengths. I have not been able to find any centration charts or other documentation explaining how to fit small, medium, and large which is pretty unhelpful on zeiss' part.
Thanks, Alex.
Have you sampled the Lite lenses? Or have had patients react?
The Light D has two fitting height options, 18 mm and 14 mm (Light D 18 and Light D 14), these are the minimum fitting height. The corridor length for the 14 is ~10 mm and the 18 is ~14 mm. The Light H has three fitting heights 14, 16, 18 (Light H 14, Light H 16, Light H 18), each of those numbers are the minimum fitting height and the corridor length for the Light H 16 is ~12 mm.OK, I'm learning. The most basic model of Zeiss' new "Lite" basic model series has a 14 and 18mm variation.14 is corridor length, I think. Ergo, for a minimum recommended fitting height for this variation, add, what? 4-5 mm? So, it's good for 18-19 mm fitting heights?Or is 14 the minimum recommended fitting height, itself?Same with 18. It could be for 22-23 mm fitting heights, or it could be the minimum recommended fitting height.I need some smart dude to set me straight.A Light D/H 14 has a 10 mm corridor length, this is pretty short so the wearer should be able to get into he near quite fast. Adding 4 mm potentially places the wearer near the intermediate portion which will definitely cause blur. This is not something we commonly hear.I've always added 4 to the minimum fitting height so people dont complain about the near zone being too low. The intermediate and Near Zones are supposed to be a few mm wider than average but the distance zone seems pretty narrow with a good amount of distortion in the periphery. I'm not sure if thats due to "Binocular optimization" or not trying to put all the bells and whistles in a lower priced lens.I will be happy to send you centration charts if you send me your email address, mine is Brent.mccardle@zeiss.comThe Pure S is a 14 mm minimum height the Pure M is 16 mm and the Pure L is 18 mm.Now Zeiss has the Smartlife "Pure" in Small, Medium, and Large to replace the Precision Pure. I have no idea what lengths Small, Medium and Large refer to and the only thing the lab could tell me was that its the same as the Precision Pure which comes in 13, 15, 17, 19, 21 lengths. I have not been able to find any centration charts or other documentation explaining how to fit small, medium, and large which is pretty unhelpful on zeiss' part.
Excellent info Grinder!
Ok, new question for Brent or other geniuses.
I'm going to make a couple of sweeping generalizations.
1. The Zeiss Individual had become the Zeiss Precision Pure/Superb (depending on whether it's fixed or variable, respectively). It is a balanced design.
2. The Zeiss Individual 2 has become the Zeiss Smartlife Individual, which comes in "Balanced" (T-shaped), "Intermediate" (V-shaped) or "Near" (hourglass).
Now, as to the subtle differences between the Smartlife Individual B and the Zeiss Pure/Superb, I will leave you to fill that in. It will be a small difference, I'm guessing.
Now, on to the "Light" portfolio, and my main questions.
The Light is roughly organized into good-better-best based on two features: one, corridor type
a. variable corridor
b. fixed corridor 3 choices
c. fixed corridor 2 choices
and the other differentiating feature is "binocular optimization". What is that, really? Designing the lenses as a pair, and trying to match zone widths regardless of distance portion powers?
And here's my big, big question about the Light portfolio: I know they're digitally surfaced, and obviously you can input corridor length, but are these lenses optimized by lens power (atoric curves)? And what is the intended design? Is it a "softer" low-astigmatism approach? It seems like it.
Also, in general, what is "digital inside"? It's described as helping near devices and reading. I understand what we were saying earlier about the Tscherning ellipse for SV near optimization. Is this just the analogue for PALs? Or, is it a corridor modification?
Last edited by drk; 07-16-2020 at 09:42 AM.
Ok, so I read up a little about the "digital inside" issue. It's described as expanding the near zone horizontally and vertically (Shamir has done something similar) to help with "digital devices" ("digital" is a poor choice of marketing terms because opticians will think about digital surfacing, not digital devices like a consumer would) and for printed material.
Now, I think everyone of all ages of all walks of life from everywhere around the globe would like that. So...what's the trade-off? Is it just more peripheral astigmatism in the near zone? Is it a reduction in the intermediate utility? Is it peripheral astigmatism above the 180?
But I will say that Zeiss should get their website updated to the new branding. Really, it's a bit of a hot mess, right now.
Not sure about this comment, but thank you!Ok, new question for Brent or other geniuses.
I'm going to make a couple of sweeping generalizations.
1. The Zeiss Individual has become the Zeiss Pure/Superb (depending on whether it's fixed or variable, respectively). It is a balanced design.
Are you referring to the original Individual? If so there have been many improvements over the years and the Superb and Pure would be much better than the original Individual.
2. The Zeiss Individual 2 has become the Zeiss Smartlife Individual, which comes in "Balanced" (T-shaped), "Intermediate" (V-shaped) or "Near" (hourglass).
Although there are some similarities between the Individual 2 and the SmartLife(SL) Individual there are some big differences as well.
The SmartLife progressive lenses have an updated fingerprint, updated object model and more accuracy when determining ray bundle diameter for optimization purposes. All of these enhancements lead to lower blur levels.
The fingerprint for the Balanced, Intermediate and Near are the same if you are comparing same add and distance power. We have moved away from hard and soft terminology, because with free form technology and optimization techniques a lens that was harder(constricted surface astigmatism in the lower half of the lens) is still much softer(i.e. less astigmatic change) in the lower lateral regions. The design is altered further for hyperopes, myopes and different add powers.
Now, as to the subtle differences between the Smartlife Individual B and the Zeiss Pure/Superb, I will leave you to fill that in. It will be a small difference, I'm guessing.
Since the Pure is a fixed corridor we will not alter the corridor length based on frame shape, PD, fitting height, etc. This could, with odd shapes, "cut-off" the add power. The Pure is only optimized for default position of wear, where the Superb and Individual have the ability to be further customized.
Keep in mind that the power is not the only variable, as you will alter the design of the lens when PoW is accounted for. These measurement help to further enhance the surface creating smoother lenses.
Now, on to the "Light" portfolio, and my main questions.
The Light is roughly organized into good-better-best based on two features: one, corridor type
a. variable corridor
b. fixed corridor 3 choices
c. fixed corridor 2 choices
and the other differentiating feature is "binocular optimization". What is that, really? Designing the lenses as a pair, and trying to match zone widths regardless of distance portion powers?
Lenses are designed independently first, then they need to be optimized as a pair or binocularly. As a wearer gazes 20 degrees the right and left the eye will be located in different positions on the lens so each global surface needs to optimized as a pair. An object model is used to calculate objects at different distances and locations to determine the best optimization at each local point on the surface and then the global surface is optimized.
The power profile of the lens will also need to be optimized binocularly to reduce aberrations along the eye path.
And here's my big, big question about the Light portfolio: I know they're digitally surfaced, and obviously you can input corridor length, but are these lenses optimized by lens power (atoric curves)? And what is the intended design? Is it a "softer" low-astigmatism approach? It seems like it.
All ZEISS Light and SmartLife lenses are optimized for lens power, although, atoric is a simplistic way to view the surface, it is easier to use this term as a description.
You will not see one design type with SmartLife or Light, the purpose is to produce the smoothest global surface(low-astigmatism) as possible. SmartLife has added enhancements which help to reduce blur levels when compared to Light. As stated above this will vary with lens and add power.
Digital Inside is an optimized power profile(or "corridor modification"), therefore, it would not be included in SV.Also, in general, what is "digital inside"? It's described as helping near devices and reading. I understand what we were saying earlier about the Tscherning ellipse for SV near optimization. Is this just the analogue for PALs? Or, is it a corridor modification?
We know that a person who wears progressive lenses looks down 28 degrees and views a digital device(tablet, phone) at 35 cm(SV wearers view these object at 30 cm). A wearer will need an added amount of power along the corridor to view a digital device and as there wearer views standard near objects at 40 cm the power is reduced to the prescribed add power.
I had a sit down with a Zeiss technologist earlier this year but I couldn't pin down how they were modifying their designs to be more mobile phone friendly- shorter/faster/higher corridor power profile, or an overpower low in the corridor. The former seems like it would work for intermediate presbyopes, relying on depth of focus for work distances shorter than 40cm, the latter for absolute presbyopes, or a combination of the two.
The proof is in the pudding of course, but I never received a voucher to evaluate effectiveness and any potential negativities, that is, reduced quality of vision on the primary gaze.
Best regards,
Robert Martellaro
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.
I appreciate your response.
https://www.zeiss.com/vision-care/us...nses-pure.html
I did find this link that describes the "Std, Med, Short" seg ht numbers.
Std = 17-19 high
Med = 15-17 high
Short = 13-15 high
LG, are they renaming the Precision Pure/Plus/Superb into the newer Smartlife terminology?
https://www.zeiss.com/vision-care/us...nses-pure.html
I did find this link that describes the "Std, Med, Short" seg ht numbers.
Std = 17-19 high
Med = 15-17 high
Short = 13-15 high
This link is to our Precision Portfolio, where the Pure had fitting heights of 13, 15, 17, 19 and 21
SmartLife Pure has three fitting height(S = 14, M = 16, L = 18)
LG, are they renaming the Precision Pure/Plus/Superb into the newer Smartlife terminology?
The Precision Portfolio is currently active, however, it will eventually be phased out. The SmartLife Portfolio is what we will use moving forward. We kept the lens names the same(i.e. Individual, Superb, Plus, Pure) to ease confusion when an ECP changed from the Precision to the SmartLife.
I have no interest in getting all up-to-speed on a product with a sunset.
What is it going to be, then? The SmartLife Individual and the Light and that's it? (Not that there's anything wrong with that...)
Or, are you saying the Precision BRANDING is going to be retired? And the designs will live on?
This is important to me, if you can clarify.
My apologies for being unclear.I have no interest in getting all up-to-speed on a product with a sunset.
What is it going to be, then? The SmartLife Individual and the Light and that's it? (Not that there's anything wrong with that...)
Or, are you saying the Precision BRANDING is going to be retired? And the designs will live on?
This is important to me, if you can clarify.
The SmartLife Portfolio includes four progressives, one anti-fatigue lens and two free form single vision lenses.
The four progressives in the SmartLife portfolio are Individual, Superb, Plus and Pure. The anti-fatigue lens is called SmartLife Digital Lens and the two free form SV lenses are called SmartLife SV and SmartLife Individual SV.
We kept the same progressive names as the Precision Portfolio, but the designs are different.
ZEISS Light Portfolio is different from SmartLife and it only includes three progressives, Light D, Light H and Light V, this portfolio is not part of SmartLife.
I'm making you earn your money, here, Brent.
OK, so
1. the Precision lenses are going to be or have been re-branded as SmartLife lenses
2. the Precision lenses are going to be re-designed when they're re-branded? Or they have already been re-designed and re-branded?
I'm making you earn your money, here, Brent.
OK, so
1. the Precision lenses are going to be or have been re-branded as SmartLife lenses
2. the Precision lenses are going to be re-designed when they're re-branded? Or they have already been re-designed and re-branded?
Ha! I can justify my pay this week 😀
1. The Precision portfolio is separate from the SmartLife portfolio. It is not re-branding, but the progressive names of each portfolio are the same. We currently offer both portfolios, SmartLife was introduced in November of last year.
2. The Precision portfolio will eventually be discontinued. The new portfolio going forward is the SmartLife portfolio.
There is no difference in regards to power ranges, fitting, materials, coatings, etc.
There is a design difference from the Precision to the SmartLife.
Holy smokes that's confusing.
So if I want to order the new Precision Pure, for example, how does Zeiss know I want the new Smartlife portfolio Precision Pure?
Public service announcement.
I am wearing a new pair of Zeiss Officelens Room.
I am literally astounded by the quality of these optics. I don't think I've ever seen this clearly. It's like wearing butter.
I'm not exaggerating.
There are currently 1 users browsing this thread. (0 members and 1 guests)
Bookmarks