My Edge Thickness RESULTS...

[Eddie G's]

Ok I made a display of all of my -8.00 sph SV stock lenses and here are my findings...

From thickest to thinnest

Regular plastic = 10.6mm (edge thickness)
Centoptic 1.56 plastic = 8.8mm
Ao rugged polycarb = 8.7mm
Zeiss 1.60 Aspheric = 8.7mm
Resolution AS Poly = 8.2mm
Essilor 1.67 Aspheric = 7.0mm
Centoptic 1.74 AS = 6.7mm
*****UPDATE*****
ESSILOR 1.74 AS = 6.6MM
Zeiss 1.74 AS = 6.3mm

These were all cut into the same frame and the same PD of 62mm was used.
(frame A=52 B=46 ED=52 DBL=22)
:cheers:

[drk]

Hey, good study!

I confirms to me that I like Resolution Poly with it's 1.2mmCT.

What I'd really like to see studied is how sensitive people are to different abbe values. For example, 100 people in a double blind study evaluates a low-chroma lens, like Trivex versus a mid-chroma, like Finalite, versus a high-chroma like poly or 1.67. How much of the chromatic abberration worry is useless?

Honestly, I think it's an overblown issue. I feel kind-of "bourgeois" in saying this, but I put a lot of people in this Resolution-brand polycarb, and Essilor's Airwear. I don't do the 1.6 thing, anymore.

If you were to add three other columns, "weight", "chroma", and "price", (and perhaps from a lab optician's perspective: "workability") and then put ordinal values on each material for each category specified, you would see that polycarb wins. (I did this, once).

Now, that's a bit artificial, as we don't have to identify "the overall best single lens material", but it sure is informative. And it also makes clear the reason why I think this:

A.) polycarb for everyone (90%), except:
B.) high minus (-6.00 and up) goes to ultra-high index (10%)
C.) "scratchers" get glass (at their own peril) (<1%)
D.) "pickies" get mid-index-CR-39-like Spectralite, Trivex, or even CR39 (<1%).

Thoughts?

[Fezz]

Thanks for the interesting post. I too would like to see a "study" on abbe value and patient satisfaction. I have talked to so many fellow opticians who "hate poly because of the low abbe value(30?)" that would rather sell 1.66/1.67 high index(32?) because "the optics are so much better than poly".! I don't get it.

Fezz
:cheers:

[LENNY]

what do you think will happen if we reduce the decentration and eye size 4 mmm each?
Would the lenses change the places ?

[drk]

That would affect all lenses equally.

[Spexvet]

Hey, good study!

I confirms to me that I like Resolution Poly with it's 1.2mmCT.

...

Now, that's a bit artificial, as we don't have to identify "the overall best single lens material", but it sure is informative. And it also makes clear the reason why I think this:

A.) polycarb for everyone (90%), except:
B.) high minus (-6.00 and up) goes to ultra-high index (10%)
C.) "scratchers" get glass (at their own peril) (<1%)
D.) "pickies" get mid-index-CR-39-like Spectralite, Trivex, or even CR39 (<1%).

Thoughts?

My thoughts, for what they're worth:

A.) I sell about 75% poly. :) And I don't have a rejection problem.
B.) I use 1.67 for high plus, too - aspherics come out really nice. I used to use Hoya's 1.70/1.71, but have converted to 1.67.
C.) I use TD2 coating for "scratchers". I sell only about 2 pairs of glass a year.
D.) You forgot those unwilling or unable to pay for a "premium lens material", who will use CR-39. Agree "pickies" need as few variables as possible. Ideally, leave them in whatever they were wearing (except glass, of course).

I've never specified Resolution. Is it really that much better than airwear?

[Dot the Eye]

I saw a Colt's laboratory study a few years back that stated (if I remember correctly) that until you get to -4D or so, the average patient won't be affected by the chromatic abberation of a low ABBE value material, and then it was only a given distance from the OC. Wish I could've found the reference ...

Dottie

[LENNY]

drk!!
You said : That would affect all lenses equally


I dont think so.
I think that items 3,4,5 could change plases because of asphericity issues!!!!

[dcdwn]

i have seen abbe ,weight ,light values on some lens from walman optical . they were poly ,cr-39 hi index 1.6 and glass . i feel that trivex is one of the best lens on the market today. and will one day replace poly it has a drilled stress of about 120 lbs. as compaired to poly. i do use poly for children glasses only because of cost.

[Fezz]

I am also growing fond of trivex. I am using more and more of it. Almost all of my drilled mountings are getting it. Much less 'cracking' at the drill holes then poly.

Fezz
:cheers:

[Jacqui]

We're also selling a lot of Trivex. Seems some of our customers are using it as a replacement for CR-39 and poly.

[Specs]

I've basically replaced polycarb withTrivex. If someone specifically mentions poly, I'll explain the differences and let them choose. Every now and then I would get a polycarb rejection due to chromatic aberation or some other visual reason, I never get a rejection from Trivex. If its better for the patient, then its better for me.

[Spexvet]

I have a hard time finding a good reason for Trivex. It's about as thick as CR-39, I don't have a rejection problem with poly, and it costs more. I'll need some convincing before I make the switch.

[For-Life]

I have a hard time finding a good reason for Trivex. It's about as thick as CR-39, I don't have a rejection problem with poly, and it costs more. I'll need some convincing before I make the switch.

I do not have troubles with poly (I use an aspheric brand), so I am in the same boat. It is cheaper for me to get aspheric poly with a top end AR than to get Trviex, and poly is thinner. I can also get 1.6 for cheaper than Trivex too, so I just cannot find a place to use Trivex.

Where I do like Trivex is for my high rx flat-tops especially plus jobs. For some reason I cannot get a good AR on a 1.56 index flat-top anymore since Sola, Essilor, and Zeiss have told me that they will not guarentee the AR since they get their FT's from X-Cel and X-Cel puts a scratch coat on them. So I use Phoenix with Super Hi, and it does a great job.

[phurley]

Hi,


I have used Spectralite with good success. Most of them were high index, I believe. My problem is scratching and the thickness of the lenses.

My new optician gave me polycarb after I told him I wanted Spectralite because they didn't scratch.

He told me that they didn't scratch because of the coating. He gave me polycarb anyway with the coating and they are all scratched already after about 3 or 4 months. (I am pretty tired of the opticians anymore. I am beginning to feel like I am dealing with car salesmen.)

What lenses should I be using to get the benefits of being thin with the ability to not scratch?

Thanks,

Patrick

[chip anderson]

Opticians are rapidly becoming carsalesmen. Get glass it is very hard to scratch, the coatings don't fail after 11 months like spectralite. You'll see better and isn't that what glasses are really for?

[fjpod]

What was the center thickness of the AO rugged poly?

[phurley]

Opticians are rapidly becoming carsalesmen. Get glass it is very hard to scratch, the coatings don't fail after 11 months like spectralite. You'll see better and isn't that what glasses are really for?

Yes it is about seeing better. What type of glass? Can I use glass with Flexon 123 by Marchon 135 Frames? It says 49-21-135 and they are rimless at the bottom.

Thanks,

Patrick

[Chris Ryser]

Opticians are rapidly becoming carsalesmen. Get glass it is very hard to scratch, the coatings don't fail after 11 months like spectralite. You'll see better and isn't that what glasses are really for?

Chip is totally right..........................

This thread reads like eberybody is out to find the most expensive version.

Has any of you guy's at abytime looked into the technique of moulding oarts of anything made with polycarbonate ?????????????? Do some search ask.com / inktomi which are superb search engines for technical matters.

You will find that poly is the cheapest material to use and make in the molding industry and you are selling the lenses made that way at prime prices.

[QDO1]

not wanting to throw a complete spanner at the thread but.. When I consider a lens for a patient I look at

• frame size - it wasnt so many years ago they were all massive!
• Index
• Abbe value
• mechanical stability
• tintability
• photochromic options
• reflectance and coatings
• weight
• virgin lens colour
• base curves
• lens form and use of Atoric / aspheric surfaces
• the old pair of glases
• durability
• stability in proposed environment
• visual aciuty in both eyes (we wouldnt want to be dispensing glass to somone with vision in 1 eye only)

Thinness/thickness is important, but isn't every thing

[QDO1]

I have a hard time finding a good reason for Trivex. It's about as thick as CR-39, I don't have a rejection problem with poly, and it costs more. I'll need some convincing before I make the switch.

You will dispense it the day you you want quality of vision and excelent impact absorbing qualities more than thinness

[Darryl Meister]

You will dispense it the day you you want quality of vision and excelent impact absorbing qualities more than thinness

But keep in mind that 1) Trivex is no more impact-resistant than Poly, 2) Trivex is considerably more expensive than Poly, 3) Trivex has a very limited availability compared to Poly, 4) Trivex is significantly thicker than Poly, and 5) Trivex still has a relatively low Abbe value compared to Glass or Hard Resin. It's a good lens material, but it has a rather limited feature set -- especially compared to Poly or the High-Index Urethanes like MR-6/7/8/10.

[QDO1]

But keep in mind that 1) Trivex is no more impact-resistant than Poly, 2) Trivex is considerably more expensive than Poly, 3) Trivex has a very limited availability compared to Poly, 4) Trivex is significantly thicker than Poly, and 5) Trivex still has a relatively low Abbe value compared to Glass or Hard Resin. It's a good lens material, but it has a rather limited feature set -- especially compared to Poly or the High-Index Urethanes like MR-6/7/8/10.

As I said, Trivex is an excelent alternative to polycarbonate, which I dispense for saftey reasons, abbe value, and chemical resistance issues. When one looks at 2 lens materials there is always a balance of advantages and disadvantages. I would say if saftey is the issue then an excelent abbe value is more useful than thinness. The obsession with thinness is daft, considering the eye sizes of frames used nowadays

[Darryl Meister]

I suspect that if safety is the biggest issue, we are often dealing with recreational or occupational eyewear, in which case the cost could potentially be a bigger issue than the slight reduction in chromatic aberration -- which would only be noticeable in higher powers. For that matter, many parents seem reluctant to spend a great deal of money on their children's eyewear, which often employ impact-resistant lenses.

However, if Trivex is your lens material of choice, there is certainly nothing wrong with that.

[QDO1]

I suspect that if safety is the biggest issue, we are often dealing with recreational or occupational eyewear, in which case the cost could potentially be a bigger issue than the slight reduction in chromatic aberration -- which would only be noticeable in higher powers. For that matter, many parents seem reluctant to spend a great deal of money on their children's eyewear, which often employ impact-resistant lenses.

However, if Trivex is your lens material of choice, there is certainly nothing wrong with that.

its a bit more complex than that.. In the UK the saftey spex market is sewn up by British standards, and at the moment the only people licenced to manufacture to BS are not offering Trixex. The trivex market is sold to recreational users - DIY, kids, sports... and in that market, price is less of an issue. Im currently in talks with the local police constabularlary, with a view of changing thier spec for police drivers, from un-coated poly to coated Trivex, on the grounds of performance. We have a pretty good argument