ANTI REFLECTIVE (ANTI GLARE) COATINGS
Anti Glare (otherwise known as anti reflective) Coating is a layer that is bonded onto one or both sides of your lens. Getting this added will minimize or eliminate reflections from shiny and glossy surfaces like computer screens, windows, and cars. It also increases the amount of light passing through the lens into the eyes.
TYPES OF ANTI GLARE COATINGS
When anti reflective coatings first came out, they were only available in single layer coats, but now, most all of them have 'multi-layers' which add to the effectiveness, quality and the resistance to scratching an smudging. So if you got anti reflective coating on your eyeglasses 30 years ago and gave up buying it because it scratched too easily, you may want to consider them again for your glasses.
The quality of these coatings on the market can vary but what will really make the difference in quality is whether the coating is applied to both sides of the lenses or just the back side. Coatings on both sides will enhance the effect. Further, look for a "hard coat layer" and a layer added to improve scratch and smudge resistance. A lot of the newer higher tiered coatings have what is similar to a scotch guard protection layer which repels oil, liquid and grease.
PROS AND CONS OF ANTI REFLECTIVE COATINGS
Can make your lenses look thinner
More light passes through your lenses
Glare and reflections are reduced
Night vision improvements
Your eyes are more visible to others while wearing your glasses
More smudges and harder to keep clean
Coating can become damaged in high heat
SCRATCH PROOF COATINGS
If all lenses were still made of glass, we would not really need to use scratch proof coatings, but since most eyewear now uses plastic (more versatile, and lighter weight), scratch resistant coatings are the norm.
Scratch proof coatings are applied either to the front side of the lens because that is where most of the scratches occur, or to both sides. If the scratch coating is pre-made into the mold of a stock lens, it will generally have it on both surfaces.
Caution: High heat can also damage this type of coating causing small stress lines or breaks called surface crazing.
ANTI FOG COATING
If your eyeglasses lenses fog up because of quick changes in temperature (e.g. cooks, ice skaters or skiers and other athletes), then an anti fog coating could help minimize it. This is a resin based coating applied permanently to the lens which absorbs moisture. Anti fog sprays are also available if not permanently applied to your glasses already.
Mirror coatings look just how the name would imply. This is a special coating - often applied to sunwear which give the appearance of a two-way mirror. It makes prevents the observer from seeing your eyes while you wear them, but you can see out of the lens normally.
One drawback is that since the mirror is reflecting a lot of light, the lens does not get to transmit as much light through the lens, which can reduce light into the eye. However, they work great for anyone outdoors exposed to intense sunlight or reflections from snow. We recommend these for skiiers, snowboarders and many outdoor athletics.