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streda 18. februára 2015

How to Keep Anti-Reflective Coatings from Peeling and Scratching

Do your glasses lenses look like this?
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I've often had patients return with several year old lenses (or even newer if they are rough on their glasses!) with lenses that are scratched and coatings that are distorting.  For many of these patients, their frustration with the loss of performance out of their lenses tempts them into wanting to replace their lenses without anti-reflective coating protection.  Typically the surface distortions and scratches on glasses with light use are on that top layer of anti-reflective coating, and not deep into the plastic lens material itself.  But if you have ever had glasses made without anti-reflective coating, you know that you are compromising performance greatly by having sheets of glare that form across your eyes every time you are exposed to light.  Here are the best ways that you can have that glare protection, but keep your glasses performing at their highest even years into their lifespan!

Do I need Anti-Reflective Coating?
Coatings are softer than the plastics underneath, so they are easier to distort or scratch.  If you are thinking about compromising by going without glare coatings on your next pair, ask yourself these questions first:
  • Do you drive at night?
  • Do you use a computer often during the day?
  • Do you work in fluorescent or bright lighting?
  • Do you have a prescription of +/-4.00 or higher?
    AR coatings are about a lot more than how you look in
    photographs.  If you work around back-lit devices, you
    know that the glare off the screen shining across your eyes is a
    leading cause of end of day fatigue.  Keep your eyes feeling
    fresh on digital devices and computers by investing in specific
    blue-blocking AR coatings. via
If you answered yes to any of these questions, your glasses will perform significantly better if you purchase anti-reflective coatings with your glasses.  Anti-reflective coatings prevent oncoming light from headlights or computer screens from causing sheets of glare across your glasses.  Light hits your lenses and instead of reflecting back across your eyes, it instead becomes absorbed or negated by the coatings in place.  The best performing anti-reflective coatings cover the full spectrum of visible wavelength light.  If you are a computer user or night driver, I highly recommend specific blue-wave length reducing AR coatings like Crizal's Prevencia or HOYA's Recharge that are designed to reduce that annoying LED screen glare off your electronic devices and reduce end of day fatigue.  Wouldn't you like to feel less eye strain at the end of your day?  If you answer yes, you need anti-reflective coating.

How to Protect Anti-Reflective Coating?
So I know that what I'm about to say may be hard to admit, but anti-reflective coatings don't just peel by themselves.  The best way to prevent your glasses from scratching and peeling is to take care of them properly.  Yes, these coatings are softer and easier to scratch than plain plastic, but being consistent and vigilant in your care will keep your glasses performing for years.  Here are some basic rules to follow:
  • Only Clean your Glasses with the Right Materials
Tempted to clean your glasses on your coat or shirt?  Don't!  Yes glasses will smudge as you go through your day, especially if you frequently touch them or around your face.  Oils from your skin will easily collect and smear on the lenses.  For myself, I lean into a microscope multiple times a day, so my glasses always have the rubber microscope eyepiece smudges to remove.  But if you clean your glasses with the wrong materials, you will eventually scratch and wear away the surface coatings.  NEVER clean your glasses with tissue paper, rough washcloths, Kleenex, or paper towels.  These materials are much too rough and will wear away a surface coating fast.  Kleenex and paper towels are made from wood fibers, so if you reach for one, just imagine rubbing your glasses with a stick from outside.  That's basically what you are doing.  Your doctor's office will almost always provide free cleaning cloths and sprays for you to use so that you can keep a few in a purse or desk drawer.  If you don't have access to lens cleaning cloth, then the only at-home material you should use would be an old soft cotton t-shirt (something that is several years old and through multiple wash cycles works best) and just a small amount of diluted Dawn dishwashing detergent will work in a bind.  That's it -- don't try any other do it yourself options.  Never clean your glasses with alcohol or alcohol based soaps!  These will strip away the coatings very quickly if you use them consistently.
via

Are you frequently cleaning your glasses but hate carrying around a cloth and lens spray?  Try out a premium lens cleaner like the Peeps by LensPen, small enough to fit in your pocket or even as a key chain, and it will clean your glasses of smudges instantly without any risk of scratching since it uses ionic attraction to pull oils and smears from your lenses without any rubbing across the surface.  You can read more here.
    • Avoid Extreme Temperatures
Many people will lead their sunglasses or driving glasses in their car, but be warned, extreme heat will break down your coatings with time and cause peeling and distortion.  If you have to leave your glasses in your car, make sure you have them in a case and try to park your car in a covered deck or under some shade to reduce high temperature exposure.   If you are consistently exposing your glasses to extreme temperatures, just expect that you may need to replace your glasses more consistently as well.  Professions like chefs or kitchen workers who expose their glasses to high temperatures and steam may have to replace their glasses more regularly as a result.

Take Home
The average AR coating should last about 2 years in my experience under moderate temperature and cleaning abuse,but if you are exposing your glasses to more extremes they could break down within a few months.  Invest in a lens warranty if your work environment is more demanding or you know that you aren't consistently good with cleaning your glasses the right way.  Most vision insurances provide benefits towards new lenses on a yearly or every 2 year basis, so replacing your glasses on that timeline should suffice for most.  If you want lenses to last for longer, then your best bet is to follow these guidelines carefully every day.  I have had AR coated lenses that have lasted for over 5 years now without signs of distortion, so with proper and diligent care it is possible!


5 komentárov:

  1. Very well written Dr L...Thank u so much sharing for this !!!

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  2. I think it is worth adding that some lenses, without coatings, can last almost forever. The coatings are the weak link in the chain. I have a pair of high index GLASS (not plastic) lenses made more than 25 years ago which migrated from all-day use for probably 5+ years, to use at my desk for more than a decade. I still use them for most of every work day. They are left on my desk, cleaned with anything I can find, basically not cared for in any special way. They are still clear and flawless, and noticeably better than coated glasses a year or so old. I use them for many hours a day in front of a computer. I've replaced the arms and nose pads, and I think the metal frames, which have long since lost their original finish, will fall apart long before the lenses show signs of wear! I don't think plastic lenses promise this kind of performance, but I certainly know that coatings don't often last longer than 2-5 years if you wear them every day, even when following a careful cleaning regime.

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  3. Why would my anti glare coating look like it has zebra stripes when I look at it in the florescent lights..? like distorted wavy lines ..

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  4. the coating sucks! certain places won’t sell without the coating!

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