In AR, it’s what you don’t see that counts.
Anti-reflective (AR) coatings are all about making lenses invisible, so nothing gets in the way of your patients’ view of the world. But AR coatings don’t achieve this equally well. Here are a few things you want to see (or more accurately not see) in an AR coating: reflections, scratches, and smudges.
All AR coatings have some residual reflectance. Traditionally, these reflections are in the yellow-green part of the spectrum, where the eye is most sensitive. Premium AR coatings from ZEISS shift the reflections into the blue range, decreasing their intensity by as much as 50%. The result is clearer lenses and a more attractive residual color.
Scratches are more obvious on AR lenses because there are no reflections to conceal them. Fortunately, there’s a way to gauge the scratch resistance of a lens without having to throw it repeatedly onto the sidewalk. Many coatings manufacturers use the Bayer abrasion test, employed by COLTS Laboratories™, an independent testing lab. Premium AR coatings today have Bayer scores of 6 or higher (higher is better), and actually outperform standard hardcoats.
The best AR coatings feature topcoats that provide a smooth cleaning surface, and actually push droplets of water and oil away from the lens surface so they wipe easily away. This ability to repel droplets is often measured by contact angle, which basically shows how much of the droplet actually touches the lens surface. Premium AR coatings from ZEISS have contact angles of up to 110°, so they wipe away almost effortlessly.
ZEISS invented the AR coating, and it continues to lead innovation today. Trust ZEISS to provide your patients with the best visual experience-and the least noticeable lenses.
|By shifting the residual color to blue, ZEISS lowers the reflectance of the lens.
||A higher contact angle makes lens cleaning easier.|
Carl Zeiss Vision, Inc. 800-358-8258 zeiss.com/lenses