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Thread: Scratches on Lenses

  1. #1
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    Question Scratches on Lenses

    Anyone who has alot of knowledge in labwork, etc., I have a question for you.

    Why is it that so many lenses come back from the lab with scratches?

    A customer called today (she picked up her glasses yesterday) and said that although the scratches do not seem to obstruct her vision, when she holds the glasses in one of the full-spectrum natural lights that she has at her desk, she sees all kinds of scratches that look like someone took a cloth and was cleaning the lenses...making scratches with every circular swipe.

    Is it possible that some scratches do not affect the lens and vision? I would like input and opinions on what type of scratches are acceptable and what type warrant a return visit to the lab.

    I know from personal experience that after a couple of years with a pair of glasses, they begin to scratch and the scratches do affect my vision when I look into the sun or a light.

    Thanks.

    p.s. I think this is a major problem, I have worked at more than one optical shop and it is rare to get lenses back from the lab in perfect condition.

  2. #2
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    Forgot to mention the lenses with all the circular scratches were Variluz Panamic 1.74 High Index/Crizal.

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    I think there is a myth in the optical business that one can clean a lens with a lens cloth and not scratch it. This amazes me, because these lens cloths are used over and over again, and they pick up dirt over time. I have questioned staff about this, and they say the do it all the time (as if doing it all the time makes it right).

    It is usually hard to see the scratches put on a lens by a single cleaning with a dirty lens cloth, but there is no question that many opticians or labs do scratch them.

  4. #4
    OptiBoard Apprentice Warspite's Avatar
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    Ok, this is a pet peeve of mine and something I hope i can help you with. As for the lens clothes that are handed out with A/R coatings; lens clothes were originally handed out with A/R coated GLASS lenses because lens cleaners at the time had far too much detergent and left a residue on the GLASS lenses. The cloth was intended to be used after the lenses had been cleaned to remove any soapy residue left over, or minor finger prints that may have come into contact with the lenses during cleaning. NOT as the primary cleaning cloth or material.
    Now, today, almost all lens materials are something other then glass and are obviously softer in nature and easier to scratch. If handing out a cloth with an A/R coated lens, please tell your customers that the cloth is only intended to be used AFTER the lens has been rinsed off with cold/tepid water or a very mild soap/water first, thereby removing virtually all debris that may and usually does scratch the surface of the lens. As for receiving a Panamic 1.74 with Crizal and reading your post, IF the lenses are new, less then a month old,the centrifical shaped scratches you are discribing sound more like the lab you purchased them from didnt fine/polish the lens material out completely before applying the TD2 coat and Crizal A/R coat, not because of a A/R cloth problem....however, if the patient has had them for longer then a month, more then likely he or she has used the cloth dry to remove debris and smudges left on the lenses after handling them.
    Last edited by Warspite; 02-16-2007 at 01:16 AM. Reason: spelling

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    The AR coat is probably ruined. Could have happened during edging, or insertion and possably at dispensing. This is common with Crizal AR. Thin centers, 1.2 mm, on small frames cause the lens to bend. The Alize will craze with any amount of lens flexing. You should check the lens, (the lab should have), before dispense by holding it in the light and rotating it 360 degrees.

    Quote Originally Posted by EagleEye123 View Post
    Anyone who has alot of knowledge in labwork, etc., I have a question for you.

    Why is it that so many lenses come back from the lab with scratches?

    A customer called today (she picked up her glasses yesterday) and said that although the scratches do not seem to obstruct her vision, when she holds the glasses in one of the full-spectrum natural lights that she has at her desk, she sees all kinds of scratches that look like someone took a cloth and was cleaning the lenses...making scratches with every circular swipe. ...
    Joseph Felker
    AllentownOptical.com

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    Quote Originally Posted by Warspite View Post
    As for receiving a Panamic 1.74 with Crizal and reading your post, IF the lenses are new, less then a month old,the centrifical shaped scratches you are discribing sound more like the lab you purchased them from didnt fine/polish the lens material out completely before applying the TD2 coat and Crizal A/R coat, not because of a A/R cloth problem.....
    I thought the 1.74 high index lenses already came from the manufacturer with the Crizal Alize coating applied?

    Also - these circular fine scratches didn't come from the customer - she noticed them the day after picking her glasses up.

    I talked to the customer today, and the scratches do not show up when looking into sunlight. That just seems strange to me since when I get scratches on my glasses, and look into sunlight, I see - don't know how to put this - lines going out from the glasses due to the scratches.

    She is trying to decide whether to bring the glasses back in for a remake or else try and let it go until more towards the warranty end - since that is 2 yrs. away.

    My question was (kind of) to develop an understanding about scratches and why these circular scratches on her glasses are not bothering her vision and she is not seeing them show up other than when she puts them under the natural light spectrum lamp. Does that mean they are very, very fine scratches as compared to scratches that develop after a wearer has had their glasses for years and gets scratching due to improper cleaning, etc.???

    Thanks.

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    Sounds like "crazing" to me. If it is central and round, it is probably from too much chusk pressure in the edger. You can go to a coating companies website for some good articles and pitures. Check out Opticote. www.opticote.com.

  8. #8
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    Quote Originally Posted by Warspite View Post
    Ok, this is a pet peeve of mine and something I hope i can help you with. As for the lens clothes that are handed out with A/R coatings; lens clothes were originally handed out with A/R coated GLASS lenses because lens cleaners at the time had far too much detergent and left a residue on the GLASS lenses. The cloth was intended to be used after the lenses had been cleaned to remove any soapy residue left over, or minor finger prints that may have come into contact with the lenses during cleaning. NOT as the primary cleaning cloth or material.
    Now, today, almost all lens materials are something other then glass and are obviously softer in nature and easier to scratch. If handing out a cloth with an A/R coated lens, please tell your customers that the cloth is only intended to be used AFTER the lens has been rinsed off with cold/tepid water or a very mild soap/water first, thereby removing virtually all debris that may and usually does scratch the surface of the lens. As for receiving a Panamic 1.74 with Crizal and reading your post, IF the lenses are new, less then a month old,the centrifical shaped scratches you are discribing sound more like the lab you purchased them from didnt fine/polish the lens material out completely before applying the TD2 coat and Crizal A/R coat, not because of a A/R cloth problem....however, if the patient has had them for longer then a month, more then likely he or she has used the cloth dry to remove debris and smudges left on the lenses after handling them.

    We use cloths we get from Cleveland Cotton Products (I don't work for them or receive any compensation from them). They are 16" square and are of the microfiber type. You can get them in several textures. We use the ones that look like terrycloth and the ones that feel like chamois. We keep about 25 of them at all times. When they get the least bit dirty, they are placed in a plastic bag for me to take home and launder, and you pick out a fresh one. That way, they don't get too dirty and you always have clean ones around. Problem is, that after a couple years of being laundered, they tend to start shedding microfibers. These look like near-microscopic internal cracks until you blow them off.
    DragonlensmanWV N.A.O.L.
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  9. #9
    OptiBoard Apprentice Warspite's Avatar
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    I thought the 1.74 high index lenses already came from the manufacturer with the Crizal Alize coating applied?
    The lens is generated first, whether on newest diamond lathe or older generaters, then fined or polished, cleaned, then prep for TD2 coat or Foundation depending on A/R type. I still think this is where your circular marks originated.

    Also - these circular fine scratches didn't come from the customer - she noticed them the day after picking her glasses up.
    I would assume the patient is then myopic/presb?

    I talked to the customer today, and the scratches do not show up when looking into sunlight. That just seems strange to me since when I get scratches on my glasses, and look into sunlight, I see - don't know how to put this - lines going out from the glasses due to the scratches.
    Again, i would suggest the reason this is occuring is, that the substructure of the lens material was not fined/polished out properly first before applying the Alize A/R..hence the reason she doesnt see them looking into sunlight. The Alize coating is preventing her from seeing the reflections caused by interior flaws of the lens.
    Its when the A/R coat is scratched, or the outer most layer on the lens is scratched, this is when you see the types of scratches you have on your glasses and they are easily visible in sunlight.

    She is trying to decide whether to bring the glasses back in for a remake or else try and let it go until more towards the warranty end - since that is 2 yrs. away.
    For what she paid for those lenses, I would suggest that they are not made under warranty, but in fact, they should be replaced as defective originally from the providing lab.

    My question was (kind of) to develop an understanding about scratches and why these circular scratches on her glasses are not bothering her vision and she is not seeing them show up other than when she puts them under the natural light spectrum lamp. Does that mean they are very, very fine scratches as compared to scratches that develop after a wearer has had their glasses for years and gets scratching due to improper cleaning, etc.???

    Thanks.

    As you gain more experience around the optical industry, you will notice that a variety of lens flaws and imperfections are only "visible" in certain types of light.
    Scratches typically will rarely hinder vision until they become so abundant that they start to make the lens opaque. Myopes will always notice scratches quickly and almost immediately, however, Hyperopes will almost never notice them..or for that matter, be bothered by them.
    I hope that has helped you some in understanding the situation.

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    Warspite:

    Thank you for taking the time to go through my questions/concerns one by one. Your answers really give me a better understanding of this particular problem.

    When this customer calls back Monday (and I know she will) - I think she will ask if these scratches will get worse or affect the lenses at some point in the future. In other words, should she go ahead and bring them in now to be replaced?

    The problem with this customer is that she has been dealing with getting a workable pair of glasses since November. She is, as you thought, a myopic/presb and has had to go to 2 pairs of glasses - one for everyday and one for computer. She waited 3 weeks for this last set of 2 glasses and I know she will not be happy to bring them back in for possibly another long wait.

    So - in your opinion, would you advise her to bring them back in now or ??

    Thanks for help!

    p.s. I am not happy with the way our LDO's have treated this situation. They tell the customer that they have 3 methods of quality testing with regard to checking for scratches and then they give the customer a pair of glasses with these types of scratches.

  11. #11
    OptiBoard Apprentice Warspite's Avatar
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    Sorry to take long in replying....most likely too late since she has already been in to see you. however, I would have the lab redo the lens under defective product...if the providing lab also finished the lens, then they should also have a tracing and csize they need to reproduce the lens without your customer having to return to your office until the providing lab has remade the lens. She then can return and have the new lenses inserted and you can return the defective lenses to the lab.
    Out of curiousity, what occupational lens did you fit her with for computer work? What is her RX?

  12. #12
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    Smilie

    Could this be a Star Burst type of a defect? This type of defect often times do not show up until the PT has the specs for a couple of days. Star Burst is some what hard to see, the lifgt has to stike the lens just right for it to show up. I beleive this is caused during edging and shows up later. Whether the defect is the Crizal ar or the hard coat I am not sure.
    As far as makeing the pt come in to replace the lenses, I would suggest have a pair made up before she comes in. It seems as though there is a bit of history with this client but from what I have read makeing a pair as a lab redo makes the most sense.

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