Scratch protection coating. Light weight hard resin lenses can be more easily scratched than glass lenses. Special coatings have been developed to help protect lenses from normal scratching. The modest additional cost for such scratch coating is usually a prudent investment. It is generally accepted that the ultraviolet rays in the sunlight pose potential harm to the eyes.
Special treatment is available for hard resin lenses that completely blocks hazardous UV light.
Lenses like polycarbonate and high index include built-in UV protection at no extra cost. Special anti-reflective coatings are now available for spectacle lenses, much like those used for fine camera lenses. These coatings are particularly effective for reducing eye fatigue for computer operators and anyone driving at night. And, of course, AR lenses enhance appearance by removing all distracting reflections. These are, by no means, the only lenses available.