High Index versus Poly

[drk]

Dang, check out this link:

http://www.nationmaster.com/encyclopedia/Corrective-lens

Pretty awesome.

[Chris Ryser]

easy to apply edge protection coatings ...............

.
Poly is easily eaten by chemicals such as acetone.
The only reasons to use poly are: It's light weight, and to protect the dispenser from lawyers.

Chip

Chemicals will not damage poly if properly protected. The hard coat protects the surfaces there is only the un protected edge that can start a chain reaction.
However there are now easy to apply edge protection coatings that will prevent any damage.

[Now I See]

Hi everyone!

How do you explain the difference between high index and polycarbonate to your patients? I know that high index is thinner, but is that the only benefit to the patient?

Sorry if this is a repetitive question, but I have searched the other posts and I can't find anything specific as far as what to say to patients.

Thanks so much for all of your help!

-Whitney

Hi Whitney...

The way I explain it to the pt depends on what their needs are...

For example, If the RX is SV and it's a child or any pt with a balance RX, I'll go over the benefits as far as impact-resistance, and UV protection...

If the RX is for a BF, TF, or PAL I will recommend 1.60, or 1.70 (depending on the RX, when a hi-index material is needed)...I don't usually give a choice of poly for these pts (unless it's a balance RX, or it's a money issue for the pt)...from my experience, I will rarely have trouble with material non-adapts with a 1.60 or a 1.70. *I also use 1.60 for drilled frames, regardless of the RX..I like the results better.

As far as a real explanation for the pt...I just tell them as much as I think they want to know...

I've had pts that say...'don't tell me, just do it, your the Optician, not me!'...for them, I just tell them their cost and go with it! :)

I've had others that come in and say..'what's the difference?'...for them I tell them about ABBE values and my personal experiences with the different types of lens materials they are considering and why I would (or wouldn't) use certain materials.

Best advice I can give, is get comfortable with the reasons YOU like the lens materials and what their benefits are for different applications...and share that with your patients...some will want lots of explanation, others won't want much...either way if you are familiar with the benefits of the lenses your office offers to patients, your patients will be comfortable with your suggestions and explanations.

Hope this helps a little..:)

[EyeFitWell]

One thing I hear a lot that drives me batty is the idea that High Index is "thinner and lighter" than poly.

[drk]

I think it may be true in circumstances where mass removal via thinning and/or asphericity outweighs higer indices' higher specific gravities.

But, yeah, a cubic cm. of polycarbonate will be lighter than a cubic cm. of MR7, e.g.

[Robert Martellaro]

Dang, check out this link:

http://www.nationmaster.com/encyclopedia/Corrective-lens

Pretty awesome.

Pretty solid information, although they got a little lost with...

"This qualification is necessary since best-form spherics are always better than aspherics for an ophthalmic lens application".

One thing I hear a lot that drives me batty is the idea that High Index is "thinner and lighter" than poly.

Right. In many cases the implication is that super high index is lighter in weight than mid and high index. This is simply not true (see below).

I think it may be true in circumstances where mass removal via thinning and/or asphericity outweighs higer indices' higher specific gravities.

But, yeah, a cubic cm. of polycarbonate will be lighter than a cubic cm. of MR7, e.g.

Using typical lens sizes and similar surface designs, Poly is the lightweight king up to the low to mid-teens (except for Trivex, which is lighter than all lens materials below about 9 D).

[Happylady]

I know some people have problems with poly but I think it's very few. I have right now both cr 39 and poly eyeglasses and I see just as well with the poly as I do the cr 39. My husband's eyeglasses are polycarb, also. It's not the perfect material for everything but it works well a lot of the time and is cheap which patients like.

[chip anderson]

Everyone keeps talking about how Poly is cheap. The labs I use charge a little more for Poly than CR-39. Is there something I don't know?

Chip

[MarcE]

Everyone keeps talking about how Poly is cheap. The labs I use charge a little more for Poly than CR-39. Is there something I don't know?

Chip

Poly is less expensive than everything except CR-39.

It doesn't chip, it's thin, it's lightweight, it's impact resistant and it costs only $30 more (in our shop). That is value that 85% of you patients will want. Try selling it. Your patients will appreciate getting lenses that aren't thicker that what they get at Wal-Mart.

Or you could ask your clients "Would you like the absolutely cheapest lens that I can get?" You might be surprised at how many will say no.

[Happylady]

Everyone keeps talking about how Poly is cheap. The labs I use charge a little more for Poly than CR-39. Is there something I don't know?

Chip

Yes, it costs more then plastic but less then anything else. It's thin, it's light, it's safe. I can't remember the last time I've had a patient have a problem with vision through it.

Of course, I don't recommend it to everyone. I recommend higher index lenses for stronger prescriptions, high index or Trivex for drills. I recommend regular plastic,too, if the rx is low, less then -2.00 or so.

[optical24/7]

I'm getting more and more away from poly. The responces I've got from Trivex are actually surprising to me. The most common responce is " things seem brighter" or "less dull". I wish ( and know some day will happen) more designs of lenses will be available in Trivex.

It's not for every Rx, and it's not available in some designs we select for patients, I hope to see it's usage and availability increase soon....





*(this will only happen if the "evil empire" acquires the patent on Trivex...)