LENS MATERIALS Conventional Plastic Hard resin plastic lenses are half the weight of glass lenses, and can be tinted any color and intensity. Optional scracth coatings help protect their surface from wear and tear. Ultra-Thin Plastic (Hi-index) Modern technology has created hi-index plastic lenses which can be manufactured about one-half thinner than conventional lenses. In addition to being more attractive, they are much lighter in weight. Polycarbonate Plastic This type of plastic is the safest of all the lenses available. It is the preferred lens choice for children, active sports play...