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Thread: UV coating on cr39

  1. #1
    Rising Star mauroventura's Avatar
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    UV coating on cr39

    :Dhello optiboarders,
    i kindly , ask if there is someone who knows if there is a special product (used as solution in hot dipping) that , keep to do a UV cut effect on cr39 avoiding a general yellowing ( Chris , this is a question for you ;)).


    hello again.

    Mauro Ventura

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    http://www.brainpowerusa.com/shoppin...roductid=16428

    US TOLL FREE: 1-800-CALL-BPI International: (00) 1-305-264-4465



    Brain Power Inc. :: UV Blocking Dyes :: BPI UV Crystal Clear - pint

    BPI UV Crystal Clear It never boils over! BPI Crystal Clear lasts up to three months in your dye tank and provides protection to hundreds of lenses in about two minutes. This new UV dye fades less than 2% in five years, it is crystal clear in your tinting system and meets USA ANSI Z80.3 standards. Dont risk the health and vision of your patients, insist on BPI UV protection. If you dont tint you own lenses, BPI will provide the name of the nearest lab that can treat your lenses with BPI tints and UV protection. Processing time: 2 - 10 minutes. Treats more than 100 pairs of lenses.

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    Redhot Jumper Clear UV solutions..............

    Quote Originally Posted by mauroventura View Post
    i kindly , ask if there is someone who knows if there is a special product (used as solution in hot dipping) that , keep to do a UV cut effect on cr39 avoiing a general yellowing ( Chris , this is a question for you ).
    Mauro Ventura
    The only thing that Gemstone has NOT mentioned is that the famous clear UV solution stops absorbing UV at 382nm.

    Every plastic lens today absorbs UV up to 365 nm. (called UVB) Those are the wavelength that create direct burns, skin and eyes, specially around 324nm.

    UV A that reaches from 360 to 400 nm is the culprit that will provide long term damage to the eye, for example cataracts etc.

    Now if you are sick and the doctor prescribes a drug whose taste you do not like...........are you just not going to take it or you only take half of it?

    A clear UV gives you only protection to half the wavelength it should, namely 382nm and NOT 400nm. At 400nm the visible light starts and to compensate for the first bit of blue light some yellow is added.

    A clear UV treated lens is not worth the money spent for the treatment, because it stops protecting half way between 360 and 400nm.

    Some companies even sell UV meters that will show a full 100% protection at 382nm.

    Of course there are thousands of opticians and optometrists that agree that the yellowish tinge of a full 400nm absorbing lens is esthetically not nice, so they choose the lesser protection over just giving the lens a cosmetic tint to make it look better.

    Some years ago I wrote an article on the subject that got printed in optical magazines in many countries. You can look it up at: http://optochemicals.com/prism_article.htm


    :hammer:
    Last edited by Chris Ryser; 12-21-2007 at 02:42 PM.

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    Quote Originally Posted by Chris Ryser View Post
    The only thing that Gemstone has NOT mentioned is that the famous clear UV solution stops absorbing UV at 382nm.

    Every plastic lens today absorbs UV up to 365 nm. (called UVB) Those are the wavelength that create direct burns, skin and eyes, specially around 324nm.

    UV A that reaches from 360 to 400 nm is the culprit that will provide long term damage to the eye, for example cataracts etc.

    Now if you are sick and the doctor prescribes a drug whose taste you do not like...........are you just not going to take it or you only take half of it?

    A clear UV gives you only protection to half the wavelength it should, namely 382nm and NOT 400nm. At 400nm the visible light starts and to compensate for the first bit of blue light some yellow is added.

    A clear UV treated lens is not worth the money spent for the treatment, because it stops protecting half way between 360 and 400nm.

    Some companies even sell UV meters that will show a full 100% protection at 382nm.

    Of course there are thousands of opticians and optometrists that agree that the yellowish tinge of a full 400nm absorbing lens is esthetically not nice, so they choose the lesser protection over just giving the lens a cosmetic tint to make it look better.

    Some years ago I wrote an article on the subject that got printed in optical magazines in many countries. You can look it up at: http://optochemicals.com/prism_article.htm


    :hammer:
    I posted the BPI ad as they have written.:hammer::hammer::hammer::hammer: You failed to mention that you are a competitor of BPI. I am am not, nor your competitor. If you'd been on the ball, Chris, you'd have responded at least in the AM. I wondered were you sleeping or bumping another of your own threads?
    Last edited by gemstone; 12-21-2007 at 05:37 PM.

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    :D:D:p:d

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    Redhot Jumper UV can be major ripoff...................

    Quote Originally Posted by gemstone View Post
    If you'd been on the ball, Chris, you'd have responded at least in the AM. I wondered were you sleeping or bumping another of your own threads?
    Jimmy...............Actually I saw that thread only in the afternoon, so I must have been bumping around.

    UV protection, generically speaking is a very sore point in my eyes. It can be the biggest ripoff in the optical industry.

    Some products are like the one we just talked about. They do not protect the full way. Some retailers can not even check it properly because they purchased UV meters that measure at 382 nm instead of 400nm.
    The newest reports on this subject even talk about protection needed up to 425nm, but I have not seen any proof of it.

    I have seen over the years opticians and optical labs cooking lenses in the same UV solutions which were used up and dead, for weeks and getting lots of money for the treatment.

    There have been some TV shows dealing with the matter but that was before communications where like today, when an Optiboard is now reaching every country on the globe.

    The CBC did a project in Toronto about 12 years ago for which I acted as a consultant.
    About 30 pairs of glasses that had been sold as having full UV protection up to 400 nm, 15 pairs ...................also 50%.........showed no sign of ever having been in contact with a UV protecting chemical.

    The largest chain operation n the US is using a product that claims to do the application in 1 minute in the dye pot. In 60 seconds at dye pot temperatures the lens does not even have a chance of opening its pores to attract the benzophenone (UV material) into the surface, so it clings only to the surface and reads 100% on the UV meter when leaving the lab.
    However benzophenone (UV material) will dissolve with alcohols and other solvent which many lens cleaners contain. So, 3 weeks down the road there is no more UV protection left.

    Benzophenone will crystallize when cold. The lens needs the time and appropriate heat to open its pores and the attracts the UV chemical, like a magnet. This process at dye pot temperature should take at least 7 minutes 10 minutes or better even longer. When removing from solution the lens should not be washed and cleaned before it has cooled to room temperature and the lens pores have closed up. Now you have a properly done and forever working UV absorbing lens.

    Many of the big labs just want it done super fast, and they know that even if the UV treatment will not last more than 3 weeks they never see the lens come back................because nobody checks 3 weeks after the fact.

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    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
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    Quote Originally Posted by Chris Ryser View Post
    Some companies even sell UV meters that will show a full 100% protection at 382nm.
    :hammer:
    I believe, Chris, that's because current ANSI standards use 380nm as the upper cutoff for UVA (and UV in general). Biologists, on the other hand, have challenged me to show them *any* mammal that can *see* anything in the 380 to 400nm range.

    FWIW

    Barry

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    Blue Jumper

    Quote Originally Posted by Barry Santini View Post
    I believe, Chris, that's because current ANSI standards use 380nm as the upper cutoff for UVA (and UV in general). Biologists, on the other hand, have challenged me to show them *any* mammal that can *see* anything in the 380 to 400nm range.
    As far as I look at ANSI standards..................the tell you not to go lower in quality than their numbers..................I dont think they prohibit you to be better than their standard.

    Visible light starts around -/ + 400nm and what is below is callled UV.
    Some specialist's say that there is no actual proof of damage by long range UV because nobody has kept exact records for the last 50 years.

    However indications are there that there is a good chance that long range UV could or can create certain unpleasant eye conditions.

    So, then, why not protect all the way if we sell the treatment to patients for good money instead of giving him a product that goes only half way because that is the so called ANSI standard.

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    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
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    We're in agreement on this, Chris.

    So I now posit that *anyone* who gets Laser (refractive) surgery to "relieve" them of the *burden* of wearing any "eyeglasses" or contact lenses, isn't affected by UV on their cornea, anyway...

    Right????

    B

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    Redhot Jumper

    Quote Originally Posted by Barry Santini View Post
    We're in agreement on this, Chris.

    So I now posit that *anyone* who gets Laser (refractive) surgery to "relieve" them of the *burden* of wearing any "eyeglasses" or contact lenses, isn't affected by UV on their cornea, anyway...

    Right????

    B

    Reshaping of a cornea either by Laser or other means should leave the cornea as transparent as before, unless the surgeon blotches up the operation. If the operation is successful the image received on the retina should be the same as on an emmetropic eye.

    If that is the case all UV transmitted to that eye will pass through the treated and shaped cornea and will promote the same damage as in a normal untreated and unprotected eye.

    Therefore this particular eye should be protected as any other eye and not to the lowest, ANSI standard at 50% protection, but to the full 400nm.

    Eyes that have been corrected for a vision that does not necessitate Rx glasses are not protected against the sun's rays and or color deficiencies.


    :finger: :finger: :finger:

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