AR Coatings Are Not Always Necessary

Date: 07.13.15

The technology in the new Anti Reflective Coatings (AR Coatings) is very impressive, but if you don’t need this coating you can save lots of money by not ordering it. Palmer Cook, O.D. and Josiah Young O.D., M.S., two highly qualified opticians based out of Ohio, agree that AR coating is sometimes not always necessary. People often envision a car salesman selling them an undercoating on their new car when their optician starts asking about an AR Coating. Often times this car salesmen scenario is a perfect analogy.

On an untreated clear lens, 4% of light will naturally be reflected off the front of the lens, and 4% will be reflected off the back of the lens. Light that reflects off the back surface can bounce back and forth inside the lens creating a starburst effect around headlights or street lights. The purpose of an Anti Reflective Coating is to allow light to go through the lens instead of bouncing off of it. The purpose of sunglasses is to allow LESS light through the lens. The average pair of sunglasses allows only 12% of light through the lens. So paying for a coating that allows more light through the lens may be counterproductive.

 These are three aspects to consider, when determining your need for an AR Coating:

• On a clear or Transitions lens an AR Coating is very important. Clear lenses transmit the most light. Therefore the 4% of reflected light will have the most impact. An AR Coating will also make it easier to see your eyes instead of reflections off the clear lens.
• AR Coatings are the best scratch protection you can put on your lenses. Sports lenses are generally made with polycarbonate or Trivex lens material. These materials are unbreakable because they are flexible. Because they are flexible, they are easier to scratch than some other lens materials. Glass is the most scratch resistant lens material, but any average sports impact would shatter a glass or plastic lens. An AR Coating will affect light in the same way regardless of the material used to make the lens. The anti scratch benefits will be increased in lenses that are most flexible.
• An AR Coating on the back of a lens will prevent light from reflecting off the back of the lens and into your eye. It also makes the lens less porous, therefore it is more resistant to fogging. This is most important if you’re wearing flatter glasses like the Ray Ban Wayfarer. Sunglasses that wrap around your head and have taller temple pieces like the Kaenon Hard Kore are designed to keep all this UV light away from your eyes, and away from the back of the lens.

Another coating you will want to know more about is a UV Coating, or a coating to block Ultra Violet Light. Both polycarbonate and Trivex naturally block all UV Light. So if someone tries to sell you a UV Coating for your sports glasses you can assume they have no idea what they’re doing. If you need a UV Coating on sports glasses you’re buying the wrong lens material. If they sold you the correct lens material you have all the UV protection you need.

Dave DuMais
Owner and optician of ADS Sports Eyewear