some queries!!!!

[pankajoptics]

hi friends
we are new to this site.and also to despensing optics.
please clarify some of the douts which are necessary to be cleared for us.
1. please tell me the comparision between Mineral LENSES-polycarbonate lenses and CR Lenses.
please specify the benifits and drawbacks of each of them.
2. Tell me how to measure or identify the index of lenses.
3. Please tell me what is the durability of coating in polycarbonate and cr lenses. If not so what is the solution for that.
4. what is E.M.I coating
5. benifits and drawbacks of mirror-arc-hmc coating so that we can advice any of them to the patient.

[Chris Ryser]

pankajoptics said:
hi friends
we are new to this site.and also to despensing optics.
please clarify some of the douts which are necessary to be cleared for us.
1. please tell me the comparision between Mineral LENSES-polycarbonate lenses and CR Lenses.
please specify the benifits and drawbacks of each of them.
2. Tell me how to measure or identify the index of lenses.
3. Please tell me what is the durability of coating in polycarbonate and cr lenses. If not so what is the solution for that.
4. what is E.M.I coating
5. benifits and drawbacks of mirror-arc-hmc coating so that we can advice any of them to the patient.

Counter Question

I dont'want to sound rude............................. but how come you are asking such basic questions that you are supposed to know before you even should talk to a patient ??????????????

[impact500]

Chris, I guess you were born all knowing and hence cannot appreciate that many of us entered our first day in the business with little knowledge.

[hcjilson]

Dear Panka,

I take the liberty of speaking for our administrator and all of our moderators.

Welcome to our forum and enjoy your time with us! We're glad you are here. When someone asks for help we are glad to give it. As proof of that, just run a search on Help and look at the threads and responses.



Harry Jilson Cape Codger

[jediron]

Chris said:
Counter Question

I dont'want to sound rude............................. but how come you are asking such basic questions that you are supposed to know before you even should talk to a patient ??????????????


__________________
Chris Ryser
______________
DLO. NA.IC.I.T.PO

Hope I never have a question! WOW I don't think I would have answered the question like the above.
:finger:

[Chris Ryser]

Chris, I guess you were born all knowing and hence cannot appreciate that many of us entered our first day in the business with little knowledge. ……………………………

Impact500,

I wish I were, ........but compared to you, who seems to be successful in spite having entered the business with little knowdledge, ..........that did not work in my case.

It has been hard work and learning all my life. In the old day's we entered the business with a minimal type of some kind of a degree or better, or we could not work in the profession unless it was as an apprentice or technician in the back of the store doing repairs and do the cut and grind jobs on mineral lenses.

Suggestion:
After having put me in my place you could have picked up the thread and answered the questions in detail.




Hope I never have a question! WOW I don't think I would have answered the question like the above.

Jediron,
We have had some arguments before, but I am still puzzled this Sunday afternoon by your remark.

Maybe you could clear the air. You comments don't make sense.

I am not ashamed to ask questions and blame nobody for doing it. It just does not make sense when a mathematics teacher ask's somebody to teach him mathematics.

[edKENdance]

I have to back Chris up on this one. This is from the users bio.

we are manufacturers and suppliers of optical products since 1973.we deal with all kind of lenses,spectacle frames , reading glasses and other optical products

Something seems a little shady here.

[hcjilson]

is the member's birthdate. I think its safe to assume a career is just beginning. In any event, a lapse of manners is not excused by a leading post. Will someone please address the questions in this thread?

Today was the first time I have ever heard the expression "mineral lenses". I do recall that Polycoarbonate is from the "urethane" family of plastics and that CR is from the monomer (sp) family.I assume mineral lenses are crown glass but I'll leave that to someone else.

[RT]

"Mineral" is what everyone outside the US calls glass.

[paw]

pankajoptics,

To get the ball rolling, let me start with the answer to your Question 1:

Mineral lenses - in the United States, we call these glass lenses. These tend to be heavier and more breakable than the other lens materials, but also more optically superior to the other lens materials. I believe that of the three lens materials, glass is used the least in the U.S. because of how heavy and breakable they are.

Polycarbonate lenses - these lenses tend to be thinner and more lightweight than the other lens materials. They also are more impact-resistant. (That is not the same thing as unbreakable.) Because of this impact-resistant quality, in the U.S. we tend to recommend polycarbonate lenses for children, for monocular patients, for use in sports glasses, and for use in safety glasses. (Safety glasses are protective eyewear for factory workers.) Polycarbonate lenses come with a scratch-resistant coating. (This does not mean scratch-proof.)

CR or CR-39 - in the U.S., we call these plastic lenses. I believe that in the U.S., plastic is used the most. Although plastic lenses can be made without a scratch-resistant coating, most dispensers recommend that a scratch-resistant coating be put on the lens. You will be doing your customers a favor.

As far as the durability of the coating, it won't last forever. But you should advise your customers to care for their lenses properly so that they can minimize the chance of scratching their lenses.

I'm sure other Optiboarders will add to these comments.

[keithbenjamin]

Hello Aakash, welcome to Optiboard!

Here is an article that discusses refractive index, specific gravity, and Abbe value, as well as some of the differences between glass, poly, CR-39, high index and Trivex, that may be of some assistance.

http://www.laramyk.com/learn/lens_materials_1.html

...also one on lens coatings.

http://www.laramyk.com/learn/processing_coatings.html

Hope they help.

Keith

[Joann Raytar]

pankajoptics,

If you search OptiBoard for scratch resistant coating, you should find a number of threads. I believe someone mentioned that the coating doesn't preform as well in some environments as it does in others. It all depends on what the weather and terrain are like where your customers live and work.

Search OptiBoard

[harry a saake]

Priya,pankajopticsjee, namaste, and welcome to the optiboard, if your new in the business you may find a thread i started on this board, called TIPS ON DISPENSING, you may want to read over it as there are many useful tips, and i will always be glad to answer any question i can for you in that field
.....i might also suggest you get a hold of one of our premier members from India, who is on the board here all the time. His name is Sandeep godbole, and he has a third generation optical shop apx 100 miles north of New Delhi. I dont know how close that is to you, but Sandeep should be an excellent source of info on optics and in particularly about doing business in India, respectfully,Harry

[Pete Hanlin]

Hello Pankajoptics,

One thing you should consider regarding lens materials discussions you have with someone from the United States and/or Western Europe...

In the US, mineral (glass) lenses have been mostly replaced by resin and polycarbonate materials. The mineral usage in the US is well below 10%- perhaps below 5%. It may surprise some Americans to know that- in Eastern Europe and other parts of the world- mineral glass is still the dominant lens material.

Also, the US is the market with the highest polycarbonate usage at this time. Polycarbonate represents over 20% of the lenses sold in the US- a percentage that is higher than anywhere else in the world. In Asia, High-Index is used more than anywhere else.

I mention this because some of the opinions given by a US or Western Europe eye care practitioner may not take into account the mix of lenses that you may be selling. For example, a large part of creating a quality anti-reflective coating is controlling the underlying scratch coating (when coating a resin or polycarbonate lens). However, mineral lenses do not require scratch coatings...

Anyway, welcome to OptiBoard! I hope you find this a useful and enjoyable site...

[Deepak]

had this question been asked by an american christ ryser wuld have gone in great details explaining it,