Is high index marketing hype?

[drk]

Ok, I need some opinions, please. I am coming to believe this:

When it comes to thickness and optics, I've observed that

1.0mm aspheric/atoric higher quality polycarb (like Resolution) = 1.5mm 1.6 MR-6 or even the newer monomer = 1.5mm 1.67 MR-10

for most Rx's under minus 8-10 Diopters.

This leads to a general statement: (Ignoring 1.56, which has no unique qualities, and 1.74 which is reserved for the most extreme cases)

One can reduce the array of lens polymers available into two general groups:

CR-39 and the CR-39-like planets in it's orbit, such as Trivex and Spectralite
and
1.6 and the 1.6-like planets in it's orbit, such as polycarbonate and 1.66-1.67, and 1.7.

I assert that the differences in optics and thinness in the "1.6 group" are negligible.

(I do think that 1.0 mm aspheric Trivex would be the pick of the litter of the CR-39 group, and there's a little more spread in that group.)

This leads to this fitting paradigm:
In single vision high minus patients up to -8.00, go with your most economical choice of the 1.6 group.

For those sensitive to the poorer 1.6 group optics, go to the CR-39 group, namely 1.0 aspheric Trivex.

For high plus (+2.00 and up) go to aspheric Trivex immediately.

For low plus and minus Rx's, spherical polycarb is the best choice, in general, due to reduced cost.

For exceptionally high minus Rx's (approaching -10D), the higher the index the better.

[Jacqui]

drk asked "Is high index marketing hype?"

Yup most of it is, we just sell the stuff because our customers order it.

[For-Life]

This is the way I do it. Remember that myself being in Canada our centre (the right way to spell it) thickness is 1.5 for cr-39 and 1.0 for most other materials.

• Plano to -2.75 - Usually cr-39
• -3.00 to -4.75 - cr-39 or poly depending on size of frame, decentration and customer preference.
• -5.00 to -7.75 - poly or 1.67 depending on same factors
• -8.00 up - 1.67 or 1.74 depending on same factors
• Plano to +1.75 - usually cr-39
• +2.00 to +3.75 - cr-39, poly or trivex depending on frame size, decentration, and customer preference
• +4.00 to +5.75 - Generally poly
• +6.00 to +9.00 - generally poly or 1.67

Of course with plus jobs the best job you can do is frame selection. A full frame is usually a must.

[ilanh]

I'm not sure that I would agree with the statement "For low plus and minus Rx's, spherical polycarb is the best choice, in general, due to reduced cost."

Why not use plain old cr39 for low numbers?

Personally, I have not seen a huge advantage in 1.67 over Poly for -3 to -9. I cannot address the chromatic aberration issues. It may be relevant in some patients at high numbers.

[chip anderson]

Pardon me if I get confused.
What does CT have to do with index?
The ultimate question should be : Is the lens thinner at the same CT and power.
Next question is what is minimum safe (or approved) thickness in each material?

Of course a combination of each answer would reveal the actual edge/center (or centre for you Brits) thickness of a given job for comparison.

Chip

[Darryl Meister]

The difference in thickness due strictly to index is roughly:

1.55 = 9% Thinner
1.60 = 17% Thinner
1.67 = 25% Thinner
1.74 = 32% Thinner

However, you also have to factor in two other features of high-index lenses, even lenses like Trivex and Spectralite:

1) The center thickness is generally 25% thinner in minus powers
2) The base curves of many lenses are flatter and aspherized in every power, which can reduce the thickness by another 20 to 30%

Consequently, high-index lenses can be significantly thinner than traditional hard resin lenses.

[For-Life]

Pardon me if I get confused.
What does CT have to do with index?
The ultimate question should be : Is the lens thinner at the same CT and power.
Next question is what is minimum safe (or approved) thickness in each material?

Of course a combination of each answer would reveal the actual edge/center (or centre for you Brits) thickness of a given job for comparison.

Chip

I mentioned CT thickness because from my understanding in the US certain materials have a different distributed CT thickness, so a poly with a 1.0 CT thickness might be thinner than a 1.67 with a 1.5 CT thickness (if this is the way they are distributed).

So I only wrote what I wrote to assure consistancy.

[Darryl Meister]

I mentioned CT thickness because from my understanding in the US certain materials have a different distributed CT thickness,

This is correct, and an important consideration.

[Myoptic33]

Its not hype in the sense you really do get a thinner lense. Is it needed? If your a low or moderate myope/hyperope probably not unless money is no object. If your a very severe myope with 10+ diopters in some cases, its the only choice since they dont even stock cr39 past a certain pescription. I dont know how low a pescription they stock high index but if I had to guess, -3?

[LENNY]

Darryl !

Does asphericity depend on power of the lens?

[Darryl Meister]

Does asphericity depend on power of the lens?

Yes, as well as the base curve of the lens.

[Jedi]

I dont know how low a pescription they stock high index but if I had to guess, -3?

Most start at plano.

[AWTECH]

Your original question, "Is this marketing hype?", has been answered I believe. You can also see that almost every lens manufacturer will point to the advantages based on the facts that apply to their product. If a certain lens material can only be processed with a 1.5 center thickness then that manufacturer will not point out how close to the same thickness and weight a different lens will be that can be surfaced or molded to a 1.0 center thickness. A thinned aspheric lens can also make one lens appear thinner than another spherical lens. The facts are that the person prescribing the lens material and lens designs should know the plus and minus to each of these.

I recently had a technician tell me of a lab that delivered CR-39 material lenses as high index using prism thinning the receiving opticans never noticed. (The good news on this story is the lab was sold, however later went out of busines) In this case three different classes of customer were taken advantage of.
1-The end consumer (who paid for high index lenses)
2-The optical retail (who paid for these high index lenses and unknowingly passed these on to the consumer)
3-The poor lab buyer who could not make ends meet when they had to purchase the higher cost lenses to sell.

Know your products and know who you are dealing with. Pass this message on to the retail consumers of not just eyewear, contacts and lenses but consumers of almost any item. With most items consumers purchase, they know just enough to be deceived by unethical sales practices as this example illustrates.

[Jason Carruthers]

Keeping choices to a minimum benefits both client and dispenser. Any smart salesperson knows that you give customers a choice, not a menu. Make it easy for customers to buy, not confusing. "Do you want high-index with that?" might actually be a better question than, "which index do you want?"

Bottom line, high index is not hype, it's technology. But don't assume technology always translates into benefit in the eyes of your customer. Technology doesn't sell. Benefits sell. And the benefits that get you the most money are the ones that are overt and unique.

Offer your clients simple, obvious benefits that require no effort to understand.

[Chris Ryser]

Bottom line, high index is not hype, it's technology. But don't assume technology always translates into benefit in the eyes of your customer. Technology doesn't sell. Benefits sell. And the benefits that get you the most money are the ones that are overt and unique.

Therefore by advertising the selling benefits and pushing them onto the public you create the "hype" and are then wanted by pople that do not need them and sold by opticians that should not sell it to some cases.

Then.....................it has become a hype.

[QDO1]

Hi-index is just a measure of how a lens material bends light, so it is therefore not hype, just a factual measure of a lens property

CT is also a lens property, which is set to a level that is as low as possible, whilst being safe, and whilst being able to survive the manufacturing process

The overall thickness of a lens,and the relative differences between different lenses are dependant on the following

• lens size and shape
• base curve and lens form
• asphericity
• center thickness (-) /required edge thickness (+)
• lens power (and power meridians and axis)
• PD and heights

When considering a high index lens the following allso need to be considered

• reflectance
• chromatic abberation
• lens form
• base curve
• material stability
• tintability
• virgin lens colour

[QDO1]

Most start at plano.

well if you dispensed -6.00 inthe right and plano in the left.. you would want the coatings to match wouldnt you?

[QDO1]

Keeping choices to a minimum benefits both client and dispenser. Any smart salesperson knows that you give customers a choice, not a menu. Make it easy for customers to buy, not confusing. "Do you want high-index with that?" might actually be a better question than, "which index do you want?"

How about
"looking at the prescription, your frame selection and your last pair of spectacles I recomend lenses A/B These materials are different, and have A/B qualities, the difference to you will be A/B. I recommend these lenses because A/B, the thicknesses will be A/B"

[Jason Carruthers]

How about
"looking at the prescription, your frame selection and your last pair of spectacles I recomend lenses A/B These materials are different, and have A/B qualities, the difference to you will be A/B. I recommend these lenses because A/B, the thicknesses will be A/B"

That's a very good answer because it shows the client you are doing the thinking for her - and it illustrates the benefits clearly. A good way to establish trust.

[drk]

How about my general point, though, that there are two "poles" with a minimal amount of differentiation among the lenses grouped at the poles?

Ilan: add SCR and UV to CR-39 (and consider you don't have to think too hard whether the frame is semi-rimless or drill mount or not, and consider the liability reduction) and my "polycarb is cost effective at low powers" makes more sense.

[Jedi]

Therefore by advertising the selling benefits and pushing them onto the public you create the "hype" and are then wanted by pople that do not need them and sold by opticians that should not sell it to some cases.

Then.....................it has become a hype.

I'm going to be nit-picky here. Benefits actually help customers, "FEATURES" are the characteristics of a product that can be oversold or "hyped". When a optician matches a feature of a product to the needs/wants of a customer good things happen. Selling a product strictly based on the features listed is best left to Best Buy or the used car lot.