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 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. 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.