Anti-reflection, or “AR” coating, offers patients improved eye vision and health. How? Vision improves with the increased amount of light allowed to pass through your glasses lenses to your eye. When light hits the retina at the back of the eye, special cells called photoreceptors turn the light into electrical signals. These electrical signals travel from the retina through the optic nerve to the brain. Then the brain turns the signals into the images that you “see.” So, when light is reflected away from your eye, insufficient light is getting to your retina to maximize vision. But a sharper, clearer image isn’t the only benefit from AR coating.
I don’t know about you, but driving at night, or even dusk, is stressful for me. When the light fades, it becomes more difficult to see, no matter how good your vision may be. Couple low light with the glare from oncoming traffic, and it becomes really hard to see. Anti-reflection coating reduces the nighttime glare of oncoming traffic which allows light to reach the retina and improves your vision. Improving your vision while you are driving reduces stress, eye strain and headaches.
Do we need AR coating on sunglasses? The answer is yes and no. No, on the front side of our sunglasses where the dark tint protects us from glare. But as anyone can tell us, that dark tint doesn’t help much when the sun’s glare comes from behind us and is reflecting off the back of our lenses. So, yes, asking for AR coating on the back of our sunglass lens is a very good idea. And AR enhances the clarity and comfort of transition lenses without any ill-effect on the photochromic reaction to light level changes.
Many of us now use high-index lenses, exclusively, in our glasses. They are thinner and so much more attractive than the thicker plastic lenses. But high-index lenses present a problem. They reflect more light. Regular plastic lenses reflect about 8 percent of light, allowing only 92 percent of available light to hit the retina. High-index lenses can reflect up to 50 percent more light away (about 12 percent), so even less light is available to the retina. Night and other low-light driving conditions are made all the more difficult with high-index lenses.
We learned some interesting facts about the process of applying AR treatment to our glasses lenses. AR isn’t just a coating. It is several layers of a metallic oxide of varying high and low indexing of light refraction. Remember we talked about “high-index” lenses reflecting more light and, thus, allowing less light through the plastic lens, into the eye and on the retina. These individual layers of metallic oxide in the AR coating process are of alternating high/low index of refraction to act on different wavelengths of light. The highest quality AR lenses have at least seven layers, but the layers represent only about two one-hundredths of 1 percent of the thickness of the lens. That’s very thin!
Different manufacturers of lenses use different AR coating processes and offer different benefits. You might need to speak with your optician about the best AR for your usage.
A few words about taking care of lenses with anti-reflective/anti-glare coating. Mostly, follow the instructions and use the products that your optometrist or optician recommends. Don’t use any cleaners that have harsh chemicals, like ammonia. So, do not Windex your lenses! Always rub wet lenses, never dry. Rubbing a dry lens with a dry cloth can scratch your lenses, and even very fine scratches will show more on a lens treated with AR coating. But using moist wipes or wetting any lens to clean it – whether you have AR coating or not – is important.
I hope you’ve found this helpful. Casey Optical Too always recommends upgrading your lenses with an AR coating.Previous Post