Anti Reflective Coating Necessary and Worth the Trouble/Cost?

Discussion in 'Optometry Archives' started by Myrna, Jul 27, 2005.

  1. Myrna

    Myrna Guest

    I read a lot of the old posting on this topic, but I'm wondering if the
    latest technology might change the answers some.

    I'm about to get new lenses and I was going to skip the AR coating
    because it deteriorated so badly on my current pair. The opthamologist
    told me I should definitely get it since it would give me better
    vision. He also told me to not to ever use the cloth that was given to
    me for cleaning the lenses and to use only softsoap and water. Wow,
    that was a shock. I suppose I could have contributed to the
    deterioration of the coating but then the optician had not given me
    correct information. The lenses are 2 years old, but I'm not sure just
    when the lenses started to go bad.

    So is it really true that the coating makes that much difference in the
    vision? Is it worth the added maintenance? How do I know if the place
    I'm using uses a good enough place to do the coating? I also need to
    update my sunglasses. Can I skip the coating on sunglasses?

    thanks all.
    Myrna
     
    Myrna, Jul 27, 2005
    #1
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  2. Myrna

    Myrna Guest

    HI, Mike,
    He probably said the AR coating will reduce reflections and I misquoted
    this as better vision. Thanks for pointing that out. Meanwhile, is the
    reduced reflection worth the trouble of having a lense that attract
    dust and can scratch more easily?
     
    Myrna, Jul 27, 2005
    #2
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  3. I don't think that reducing reflections is at odds with "better
    vision". Since you get significantly more light through to the eye,
    night vision can definitely improve with AR, and the higher the index of
    the lens, the more dramatic this effect is. Obviously, you would pick
    up faint objects on a dark road sooner with AR than without. I'd concur
    with the o.m.d. that that constitutes "better vision".

    Newer coatings are much better in the dust and scratch departments. I
    personally think they are worth it for many people, and use them myself.

    Re cleaning, I still say NO cloth. Rinse, clean with a mild cleanser or
    soap (I prefer windex) using CLEAN fingers, rinse thoroughly again with
    warm water, then gently dry with a paper towel, no more rubbing than is
    necessary. Above all, never use those cute little microfiber cloths
    more than a few times. They load up on the dust and micro-sand
    particles, which are the real culprits...

    w.stacy, o.d.
     
    William Stacy, Jul 27, 2005
    #3
  4. I am just at the point of getting new glasses for distance and computer
    monitor viewing. I have significant experience with antireflection (AR) and
    other thin-film optical coatings although no experience with
    ophthalmological applications other than my personal ones. I have trouble
    deciding whether to get the AR coatings. I have decided to use glass and get
    AR coatings only if I can get hard durable coatings.

    In binoculars and other optical equipment, there can be many more air to
    glass surfaces than the two for ordinary spectacles. For zoom lenses, the
    reflections can lead to serious degradation of optical performance if AR is
    not used.

    I am somewhat ignorant of the kinds of coatings used for plastic lenses, but
    I suspected that they are not very durable. The key is that they must be
    deposited on a cold surface because plastic just cannot take heat. Glass can
    be heated during deposition. This can lead to extremely tough coatings. Some
    military specifications require using Scotch tape to try pulling the coating
    off and rubbing with an eraser.

    The simplest tough coating is a single quarter-wave (green) layer of
    magnesium fluoride deposited on glass at a high temperature, 350°C or higher
    IIRC. If done well, that coating just does not come off. It has to be ground
    or etched off. That coating reduces the reflectivity of a typical interface
    from 4% to 1%. Higher index glass ordinarily gives higher reflectivity, but
    performance of this simple coating improves until an index of 1.9 is
    reached. That will not happen with cost effective lenses.

    More complicated, multilayer, coatings can provide even better performance,
    but I do not think that they are used for spectacles. Mike Tyner knows more
    about such things than I do.

    Bill
     
    Repeating Rifle, Jul 27, 2005
    #4
  5. Myrna

    usenet Guest

    I always get AR-coated plastic lenses. I've had good luck, but every
    so often you come across a bad AR-coating run. Even from a reputable
    coating vendor, there is a finite chance of an AR coating flaking or
    rubbing off prematurely.

    I clean my AR coated lenses with hot tap water, soap, and fingers. Pat
    dry with paper towel. Never ever rub dry. My lenses are also
    immersion-coated to make them oleo/hydophobic. This helps me clean and
    dry the AR surface.
     
    usenet, Jul 28, 2005
    #5
  6. I know they used to, and don't know if they still do, but these days I
    don't think it's as big a deal. I use windex all the time and haven't
    noticed any problems. I used to mix up and alcohol/water/lux liquid
    concoction for AR lenses, but guess I'm getting lazy.

    If so, I'd avoid them. Decent quality paper towlels or facial tissues
    without vaseline work pretty well, as does good old TP (some brands hold
    together better than others).
    The problem with cotton and those synthetic microfibers is that they
    don't dry the lens very well like paper does, so the patient ends up
    "polishing" the lens with them, read that as "grinding" them if there's
    a single particle of micro-sand on them.

    w.stacy, o.d.
     
    William Stacy, Jul 29, 2005
    #6
  7. Myrna

    skyt Guest

    Pretty sad, but my glasses (one year old, Seiko lenses) already have
    one big patch of the AR coating missing. Even sadder is the fact that
    if I'd discovered the AR coating gone just a month earlier, I could
    have gotten them replaced under warranty...
     
    skyt, Jul 30, 2005
    #7
  8. Myrna

    Tom Guest

    I've only had AR coating once on my glasses.. never again. I noticed
    no difference in vision at all. I was told that I'd definitely need
    the coating for reading computer but I couldn't see the difference.
    The only thing was that they were hell to keep clean. So next time I
    refused. I think it's a case of the manufacturer's fabricating a need
    and then coming up with the solution. A bit like those ads for
    disinfectant when first they tell you that your baby will get sick
    from crawling around the floor...pah!

    Tom
     
    Tom, Jul 30, 2005
    #8
  9. Myrna

    Myrna Guest

    I was told by alocal optician that there is no warranty on the AR
    coating since they can't know how the consumer has cared for the lense.
    What do you make of this?
     
    Myrna, Aug 2, 2005
    #9
  10. It's a pretty cheap joint that doesn't have any anti-scratch warranty.
    Makes me think that they only have garbage coatings. Depending on which
    lab and which coatings I get, my minimum is one free redo, additional
    redos at half price. My best (and most expensive) is unlimited no
    charge redos for the life of the Rx, or 2 years whichever comes first.
     
    William Stacy, Aug 2, 2005
    #10
  11. Myrna

    Mark A Guest

    If you get a Varilux product, you can get Crizal or Crizal Alize, which are
    two of the most durable AR coatings available. Not sure if they have an
    unconditional warranty, but if it starts peeling, etc you should be able to
    bet a replacement within a reasonable time. If it is scratched, then you are
    probably on your own.
     
    Mark A, Aug 2, 2005
    #11
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