Anti-reflective coating (also called “AR coating” or “anti-glare coating”) improves vision, minimizes eye strain and makes your eyeglasses look more attractive.
Benefits of an Anti-reflective (Anti-glare) Coating
These advantages are due to the capability of AR coating to practically eliminate reflections from the front and back surface areas of your glasses lenses. With reflections gone, more light go through your lenses to enhance visual skill with less diversions (particularly during the night), and the lenses look almost invisible — which improves your look by drawing more focus on your eyes and assisting you make much better “eye contact” with others.
AR coating is specifically helpful when used on high-index lenses, which reflect more light than regular plastic lenses. Normally, the higher the index of refraction of the lens material, the more light that will be shown from the surface area of the lenses.
For instance, regular plastic lenses show approximately 8 percent of light striking the lenses, so only 92 percent of readily available light goes into the eye for vision. High index plastic lenses can show up to 50 percent more light than routine plastic lenses (roughly 12 percent of readily available light), so even less light is available to the eye for vision. This can be especially frustrating in low-light conditions, such as when owning at night.
Today’s contemporary anti-reflective coatings can practically get rid of the reflection of light from glasses lenses, allowing 99.5 percent of available light to travel through the lenses and enter the eye for excellent vision.
By removing reflections, AR coating likewise makes your glasses lenses look almost invisible so people can see your eyes and facial expressions more plainly. Anti-reflective glasses also are more attractive, so you can look your best in all lighting conditions.
The visual benefits of lenses with anti-reflective coating include sharper vision with less glare when owning at night and higher comfort during extended computer use (compared with using glasses lenses without AR coating).
Anti-reflective coating also is a great idea for sunglasses, since it removes glare from sunlight showing into your eyes from the back surface of tinted lenses when the sun lags you. (Generally, AR coating is applied only to the back surface area of sunglass lenses since there are no cosmetic or visual benefits to getting rid of reflections from the front surface of dark-tinted lenses.)
A lot of premium AR lenses include a surface area treatment that seals the anti-reflective layers and makes the lenses easier to clean up. “Hydrophobic” surface area treatments fend off water, preventing the development of water spots.
Some anti-reflective lenses have surface area treatments that are both hydrophobic and “oleophobic” (also called lipophobic), which indicates they repel both water and oil. These mix treatments generally include fluorinated products that give the lenses properties that are extremely similar to those of nonstick pots and pans.
Some eyeglass lenses have factory-applied AR coating on both lens surfaces. Other lenses, particularly progressive lenses and other multifocal lenses (i.e., bifocals and trifocals), have the coating used after the lenses have actually been tailored to your spectacles prescription by an optical lab.
How Anti-Reflective Coating Is Applied
Using anti-reflective coating to glasses lenses is an extremely technical procedure including vacuum deposition technology.
The first step in the AR coating procedure is to thoroughly clean up the lenses and check them for noticeable and microscopic surface defects. Even a small spot, piece of lint or hairline scratch on a lens during the coating procedure can cause a malfunctioning AR coating.
Usually, a production line includes numerous cleaning and rinsing baths, consisting of ultrasonic cleaning to remove any traces of surface area pollutants. This is followed by air drying and heating of the lenses in unique ovens to additional get rid of unwanted moisture and gases from the lens surface area.
The lenses are then filled into special metal racks with spring-loaded openings so the lenses are held safely but with virtually all lens surfaces exposed for the coating application. The racks are then filled into the coating chamber. The door of the chamber is sealed, and the air is drained of the chamber to produce a vacuum.
While the lens racks are rotating in the coating chamber, a power source within the machine focuses a beam of electrons onto a little crucible that contains a series of metal oxides in different compartments.
When the coating materials are bombarded by electrons, they vaporize within the coating chamber and follow the surface areas of the lenses — developing a uniform, microscopically thin optical layer on the lens.
Select An AR Coating That’s Best For You
Each AR coating producer has its own proprietary formula, however usually all anti-reflective coatings consist of several tiny layers of metallic oxides of rotating high and low index of refraction. Since each layer impacts various wavelengths of light, the more layers there are, the more reflections that are neutralized. Some high-quality AR coatings have up to seven layers.
Depending upon your lifestyle, your optician may suggest a specific brand name of anti-reflective coating. If you spend a great deal of time operating at a computer system, you may benefit from an AR coating that strains blue light. For example, Hoya says its Recharge EX3 anti-reflective treatment obstructs high-energy blue light discharged by electronic devices — such as computers, e-readers, smartphones, and even energy-efficient light bulbs — that could be harming to the eyes over time.
Depending upon the AR coating formula, many lenses with anti-reflective coating have an extremely faint recurring color, typically green or blue, that is characteristic of that particular brand name of coating.
Anti-reflective coverings are extremely thin. The whole multilayer AR coating stack usually is just about 0.2 to 0.3 microns thick, or about 0.02 percent (two one-hundredths of 1 percent) of the thickness of a basic eyeglass lens.
See also: How To Clean Glasses
Taking care of Glasses With Anti-Reflective Lenses
When cleaning AR-coated lenses, use just products that your optician recommends. Lens cleaners with harsh chemicals might harm the anti-reflective coating.
Likewise, do not try to clean AR-coated lenses without moistening them first. Utilizing a dry fabric on a dry lens can cause lens scratches. And since anti-reflective coating gets rid of light reflections that can mask lens surface area defects, great scratches often are more visible on AR-coated lenses than on uncoated lenses.