All about Anti-Relective Treatments

9~6~2023

Today’s modern anti-reflective treatments can virtually eliminate the reflection of light from eyeglass lenses, allowing 99.5% of available light to pass through the lenses and enter the eye for good vision.

By eliminating reflections, AR treatments also makes your eyeglass lenses look nearly invisible so people can see your eyes and facial expressions more clearly. 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 treatments include sharper vision with less glare when driving at night and greater comfort during prolonged computer use (compared with wearing eyeglass lenses without AR treatments).

When applied to light-adaptive lenses like transition lens, AR treatments enhances the clarity and comfort of these premium lenses in all light conditions without reducing their sun-reactive performance.

Anti-reflective treatments also is a good idea for sunglasses. It eliminates glare from sunlight reflecting into your eyes from the back surface of tinted lenses when the sun is behind you. (Generally, AR coating is applied only to the back surface of sunglass lenses because there are no cosmetic or visual benefits to eliminating reflections from the front surface of dark-tinted lenses.)

Most premium AR lenses include a surface treatment that seals the anti-reflective layers and makes the lenses easier to clean. These hydrophobic surface treatments also repel water, preventing the formation of water spots on your lenses.

Some anti-reflective lenses have surface treatments that are both hydrophobic and oleophobic (also called lipophobic), which means they repel both water and oil. These combination treatments typically contain fluorinated materials that give the lenses properties that are very similar to those of nonstick cookware.

How anti-reflective treatments are applied

Applying anti-reflective treatment to eyeglass lenses is a highly technical process involving vacuum deposition technology.

The first step in the AR treating process is to meticulously clean the lenses and inspect them for visible and microscopic surface defects. Even a tiny smudge, piece of lint or hairline scratch on a lens during the coating process can cause a defective AR treatment.

Modern vacuum coating machine for applying AR treatment to eyeglass lenses. 

Typically, a production line includes multiple washing and rinsing baths, including ultrasonic cleaning to remove any traces of surface contaminants. This is followed by air drying and heating of the lenses in special ovens to further remove unwanted moisture and gases from the lens surface.

The lenses are then loaded into special metal racks with spring-loaded openings so the lenses are held securely but with virtually all lens surfaces exposed for the AR treatment application. The racks are then loaded into the treatment chamber. The door of the chamber is sealed, and the air is pumped out of the chamber to create a vacuum.

While the lens racks are rotating in the treatment chamber, a power source within the machine focuses a beam of electrons onto a small crucible that contains a series of metal oxides in separate compartments.

When the treated materials are bombarded by electrons, they vaporize within the treatment chamber and adhere to the surfaces of the lenses — creating a uniform, microscopically thin optical layer on the lens.

Some eyeglass lenses have factory-applied AR treatments on both lens surfaces. Other lenses, particularly progressive lenses and other multifocal lenses (bifocal and trifocals), have the treatment applied after the lenses have been customized to your eyeglass prescription

 by an optical lab.