Friday, August 05, 2005

Plastic VS Polycarbonate VS Glass Lenses

In this segment I am going to talk about the different choices of material that lenses are available in.
This is another subject that was sparked by a previous comment on a prior post.
The subject was “ do I really need that, scratch resistant coating”.
In that post I stated that everyone needs scratch resistant coating because they do not clean their lenses properly so scratch resistant will help prolong the life of the lenses.
You can read that article if you like, by clicking the link in the archive section of this page.

To comment went like this:
If people just bought Glass lenses they wouldn't need to get scratch resistant coating's. It's amazing how the optical industry has brainwashed people into thinking that they need plastic lenses and then they tell them to get the lenses coated.

I have been in the optical industry for going on 17 years now,
and I am afraid I would have to somewhat agree with this statement.
That is exactly what happens, but that is also why in that post I threw in a shameless plug for my company, because I give free scratch resistant coating on every pair of lenses I sell, as opposed to most places that are pushing plastic lenses are also pushing the scratch resistant coating and charging for.

John Q. consumer has been brainwashed into thinking plastic lenses is what they need,
in fact, the deal now is everybody is pushing polycarbonate lenses,
on the premise that they are thinner, lighter, and impact resistant, which is all true,
but they are also more expensive than regular plastic lenses, of course, and just like plastic, or Glass for that matter, they're not for everybody.

So what I would like to do is discuss the pros and cons of all three of these choices.

Some of you along with myself included are old enough to remember back when we didn't have all these choices, there was a time when Glass lenses were the only thing you could get.
Then they came out with plastic lenses which everyone was excited about because they were much lighter weight, but what they discovered was they scratch easier.
The Glass lenses are a little tougher but they were so heavy.
And the mindset now days is people want their glasses to be as light weight and nonintrusive as possible, that is why they are pushing polycarbonate lenses now.

So,
Glass lenses weigh more and if you drop your glasses they may shatter because Glass is the least shatterproof.
But, Glass lenses give you the best optics, in other words you get better visual acuity through a Glass lens, and they do not scratch as easily as plastic or polycarbonate.



Plastic lenses are lighter weight, and much more shatterproof, but will scratch easier if you do not clean them properly, and you will lose a little visual acuity.
But this is still the most popular choice for lenses because most people do not want to put up with the extra weight of a Glass lens, and with a scratch resistant coating and proper cleaning they will last for a good amount of time.

Polycarbonate lenses are thinner and lighter and are shatterproof, most optical,s
you go to will also call them impact resistant which is the same thing.
You can take a hammer and smack a polycarbonate lens with it and it will not break,
so they are the safest lens when it comes to impact resistance, but once you smack it with that hammer you will not be able to see through it because it will be scratched up and dented.
Polycarbonate lenses are very soft and pliable that's why they're impact resistant,
but they also scratch the easiest, so it is a must that you use proper cleaning methods with a polycarbonate lens or their only going to last about 10 minutes.
And for some people they have some inherent distortion that they cannot tolerate,
also some people complain about chromatic aberrations as well.
So although they are the safest you are going to sacrifice some visual acuity with a polycarbonate lens.

I specialize in prescription safety glasses, and being in a safety environment, one of the things I'm faced with when I am sitting down with a safety director to discuss their prescription eyewear program is what type of lenses should we use?
You would think that in a safety situation you would want polycarbonate lenses for your safety glasses because they are the most impact resistant therefore the safest.
And in some cases that is true. But what if the workers are in a really dusty dirty or greasy grimy work environment?
The polycarbonate lenses are going to get so scratched up very quickly that now the worker cannot see through them. So is that safe if they can't see through them?
In a case like that their really better off with a Glass lens.
That way they are easier to keep clean so they can see better which makes them safer.

In summary, what you really have to do is ask yourself what is important to you,
what are your cleaning habits, and in the case of safety eyewear, what type of environment are you going to be using these glasses in?
Are you going to take good care of your glasses? Or do you know that you're not very good at cleaning them properly.
Is it impact resistance and safety that you are after?
Or do you want the best visual acuity, and if so are you willing to put up with the extra weight of a Glass lens?

So, although as I stated before I somewhat agree that we have been brainwashed,
I can't honestly say everybody should be wearing Glass lenses.
Glass lenses are not for everybody nor are plastic lenses or polycarbonate.
As I have always stated in prior post or face-to-face with my customers,
you have to educate yourself to the different choices available in eyewear and then
You Choose what is best for you!

As always, I hope this has been helpful.
I encourage any comments or questions in regards to regular glasses or prescription safety glasses, please feel free to visit my web site, where you can go to the “contact us”
page there you will find my phone number and my e-mail address.

See you next time

Ben…..aka MobileEyeGuy

http://www.mobileeyeguy.biz/

48 comments:

  1. Wow! You put a lot of thought into this.

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  2. That was helpful. Thank you.

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  3. I like your article. Do you know why it is that glass has the best visual acuity and polycarbonate the least? My background is in physics, so I'm curious as to the details of the optics.

    And here's a question for you for the future:
    Why is it that over the counter reading glasses only go down to a certain weakness? When I first needed reading glasses, I was at less than +1.00 so I had to pay a hundred dollars for prescription reading glasses. Is there just too little demand for that weak glasses?

    If you reply to either, I'd appreciate it if you left a note on my blog, Strange Musings, to make sure I come back and read it. :)

    Thanks for the info!

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  4. I hope you were not affected by Katrina...great blog.

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  5. good information. what do you think about the pierced eye glasses? (I think they are strange) Here is a link about them on this blog: http://hodgepodger.blogspot.com/2005/04/artist-invents-pierced-glasses.html

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  6. Hey thanks Tinker for the link!
    I thought in 18 years of being an Optician I had seen it all.

    Maybe I'm just getting to old.....But seems like it would be a lot easier to get these things we call "Contact Lenses" if you have a problem with your glasses slipping down your nose!
    :o)

    Ben

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  7. Anonymous5:01 PM

    I am curious about one thing. You said that polycarbonate lenses are the most scratch resistant but in this article on Webmd.com it says that plycarbonate lenses are already scratch resistant. Can you please clarify?

    http://www.webmd.com/content/article/17/1676_51168.htm

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  8. Anonymous3:34 AM

    I've been wearing eyeglasses for 40 years, and everything the initial poster was RIGHT ON; perhaps the STRAIGHTEST info you'll ever hear from a pro. The first or second generation of plastic lenses (we're going back 30 or so years as I recall) were the best of the lot - half the weight of glass, fair-to-middlin' visual acuity (i.e. a reasonably large "sweet spot"; and just in case you're wondering, I'm NOW high myopic at about -7.00), nearly indestructible, and with reasonable handling wouldn't scratch up too bad for a year or more. (I'm REALLY big on my glasses being clear, since my vision blows to begin with:-((( Polycarbonate, and even worse, the new high-index versions of said material, are the biggest RIP-OFF since Wonder Bread: over-priced, poor performance (i.e. small "sweet spot", not much thinner for high myops, AND they scratch up like hell even if you ONLY USE the expensive cleaning solutions and special cloths to clean 'em with:-(Sorta like looking through a haze after 3 days or months, depending on how pristine you are with them...)

    Listen to the OP - and make your own informed choice.

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  9. Zandperl .... About the physics ... I believe the difference and benifit glass gives over plastic polycarbs would probably have something to do with the "index of refraction" and chromatic abbreviations ...

    http://scienceworld.wolfram.com/physics/SnellsLaw.html

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    Replies
    1. You are correct,
      That is a very large part of why the glass gives better optics!

      Delete
  10. Anonymous9:59 AM

    I have been employed by the largest eyewear manufacture in the world for about a year and ½ now, the glasses are polycarbonate and very expensive, with the employee discount I can buy a pair at 125 us dollars. I thought it was just me but the glasses are terrible compared to glass lens, they scratch so easily and get smudges “if you will” or dirtier than glass (not sure why) maybe the surface is more rough or porous than glass?

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  11. Hi, it's great to read things like this - what the public aren't told about unless they ask for it. Graham - www.logo-n-stitch.co.uk.

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  12. I don't understand why polycarbonates are still on the market, other than maybe for non-prescription safety lenses. The loss of visual acuity is simply unacceptable; if your line of sight strays at all from dead center of the lens, the image colors begin to break up, like looking through a prism, which of course means you're seeing multiple images based on color. Imagine what that means to a driver in heavy traffic, trying to check the other lanes around him!

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  13. Thanks for the info - a great help as I am off to get a new pair today!

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  14. I wear polycarbonate lenses--I have since I was a kid--and like them quite a bit. I'm curious about the chromatic aberration you mention. I've never noticed it. I do notice spherical aberration (distortion when looking near the edge of the lens), but it doesn't bother me. What causes the chromatic aberration? Is the index of refraction different a different wavelengths, or is the %transmittance at different wavelengths different?

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    Replies
    1. If poly works for you that is great, that answers one of the other questions some one had "why are they still on the market", well because like you, not everyone is effected by the chromatic aberration, it has to do with the Rx, curve of lens, and thickness, or sometimes the axisof the prescription....so thats why people roll the dice to see if the benifits out weigh the side effects

      Delete
  15. Very helpful article, thank you!

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  16. Varied styles of eyeglasses have hit the market. Today, there are lot of variety in eyeglasses frames. Among them, the rimless frames are garnering a lot of popularity among today's generation. These glasses can be easily bought from on line stores.

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  17. Thanks for the "clarity".

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  18. Thanks for sharing information about pedicure cleaning and the meeting. Your blog has always been a source of great beauty tips.

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  19. Anonymous4:56 PM

    This article does not state the fact that glass lenses are quite dangerous because if they are impacted they break into razor sharp pieces of glass that would damage the eye.

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  20. You are over stating with QUITE Dangerous, A. there was a time all we had was glass, B. plastic lenses also shatter, and C. yes I did say in the article they are the LEAST shatter proof.

    for more details on why glass has gotten such a bad rap go here:
    http://www.youtube.com/watch?v=opG9bYbYG-Y

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  21. I found your article most informative and open about all types of lenses. The reason I found your blog however, was in search of an answer to my question; is there any way to tell if the lenses in your glasses are glass or plastic (without dropping them to see if they shatter). The reason for this inquiry is that I recently ordered a pair of glasses with GLASS lenses. The lenses I received have small circles and numbers in the lenses. Is this possible with glass, or did I receive plastic lenses?

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    Replies
    1. Bre - Optician5:03 AM

      This comment has been removed by a blog administrator.

      Delete
  22. Anonymous7:12 PM

    Very helpful. Thank you much for the information.

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  23. Douglas1:11 PM

    I wish my optician was you. I already got screwed by many opticians and I had to learn everything about lenses by myself. I'm really tired of having a horrible vision and paying a lot for it!
    My visual acuity is horrible and I take care of my lenses like its a baby.
    Essilor Stylis is polycarbonate or plastic?
    Do you think -3.00 and -2.25 is too much for glass lenses?
    My big problem is visual acuity and reflex. My current Hoya Miolight with anti-glare coating give me so much reflex that usually I think there is a cat or a dog in the corners, and I turn my head and there is nothing.

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  24. Thank you for this info, I was able to make a quick decision.

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  25. Anonymous7:33 PM

    Helpful article.
    Ive had glass lenses before and loved them. I then had the polycarbonate ones and just a few months in the lense coating started to peel away and was so bad I couldnt see very well.
    I have had plastic lenses for the last few pair of glasses and so far I like them almost as much as the glass.

    I think Id take glass over any of them if I could figure out where to buy them affordably.

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  26. In my case because I need thinner lenses the polycarbonate is my lenses of choice. I would love to pick glass but sadly I can't.

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  27. Nice post. Just what I needed to hear today!

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  28. This was very helpful, as I'm pretty new to glasses-wearing.

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  29. Anonymous4:28 PM

    Great info... plainly put. Thanks for sharing your knowledge and your ability to comment on it.

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  30. Anonymous2:34 AM

    I have to laugh that someone stated that they were "high myopic" at -7.00. I'm at -17.25 and -13.25. What should I call myself? (BLIND!) Anyway, I wear corneo-scleral contacts, but of course have to use glasses at times. Would regular plastic give me a noticeable difference in clarity, field of vision?

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    Replies
    1. Bre - Optician5:16 AM

      This comment has been removed by a blog administrator.

      Delete
  31. Mariam2:41 AM

    Thank you so much for posting this. This is exactly what I needed to know before getting my new glasses made.

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  32. Anonymous11:24 AM

    Answered my q's. thanks

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  33. Anonymous8:50 PM

    Thank you for this post. It helped me figure out what to get!

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    Replies
    1. Your welcome, glad I could help.
      If you have decided to go with glass lenses, and have trouble getting them locally, let me know I would be glad to help you get the glass lenses you want My lab specializes in them and I can get them for you.
      Mobileeyeguy@gmail.com

      Delete
    2. Anonymous5:24 PM

      DO I NEED ANY EXTRAS LIKE ANTI GLARE ON PHOTO GRAY EXTRAS?

      Delete
  34. Anonymous11:19 AM

    I am wearing glassess since childhood and can say easily glass eyelense is the best option.Glass is a thing given to us by nature for its optical property.Plastic or polycarbonate glassess reduce visibility.
    Regards,
    goelpankaj@hotmail.com

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  35. Anonymous8:01 PM

    Bennnn my mannnn....once again, another comment to say kudos to u for this post!!! Very very helpful info!! When I got my glasses the optician pushed polycarbonate my way!! End the end I chose plastic, and after reading this nice informative post, I'm sure I made the right decision......for me!!! Kudos to MobileEyeGuy!!!

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  36. Anonymous3:50 AM

    You article is wonderful.
    Just explains clearly what I am Experiencing. I am 57 years old.
    I have been buying contact lenses, glass , plastic and poli-carbonate types of eyeglasses.
    I even had laser Surgery . I choose to have monovision, . ( Laser surgery is not forever , eventually we end up buying eyeglasses , again ).
    In my case, the depth and the acuity is better using glass lenses.
    I love your article. God Blessed you.
    Regards.
    Manuel

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  37. The polycarbonate lenses create terrible distortions. Walk down a hall with cabinets or doors and pay attention to the curving straight lines.

    when one ages and loses the sense of balance and tries to compensate with vision watch out for problems.

    Why are do these fashion glasses have small diameter lenses? It is because to get the very thin lenses the distortion is greater. If the lens is bigger in diameter the distortion will slap you in the face. These small diameter glasses tend to be like pin hole cameras. The small diameter makes up for a lot of faults.

    Get glass or plastic lenses, never polycarbonate unless for special special reasons and know why.

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  38. Anonymous2:04 PM

    I've had glass lenses for years and the last pair i got when ever the sun hits you from behind or the side i get a red to yellowish glare at the bifocal line. i took them back got a refund and went to another store and got glass lenses and the same thing. never had this problem before and my old glasses don't have any glare. anyone else have this problem?

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  39. Anonymous5:42 AM

    That's the info I needed. Mahalo

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  40. Mike Snider6:34 PM

    With fifty years of glasses experience I can off the following:

    Glass lenses "see" the best. Hold two lenses between a light source and a good piece of white paper and notice which material transmits the most light.

    Glass lenses fly off my head more than plastic when I make "athletic" moves particularly while sweating.

    Glass lenses fog up much better and take longer to warm up when going from dry cold conditions to moist warm conditions. This can be annoying.

    Glass lenses do not let weld spatter "fly" off harmlessly like plastic. It leaves little pits in the glass.

    Glass lenses with stand my "Cleaning" many time more than the best coated plastic even when I have tried to be careful.

    Money not a factor: get both

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    ReplyDelete