Plastic Lenses - 1.56 Index
Working With Plastic Eyeglass LensesMost lenses are plastic (glass is still available, but heavier and more expensive), but the least expensive plastic used for eyeglass lenses is called CR39 hard resin lenses. Hard resin lenses are good for everyday use. These lenses have the least distortion of any non-glass lens. For children or active adults engaged in sporting activities, we strongly recommend polycarbonate (impact resistant) lenses. If the sphere on your prescription is higher than +/-3.00, you will benefit from the selection of a high index lens type. If the sphere on your prescription is higher than +/-4.00, we recommend a thin lens type. Thinner lenses have three advantages: they do not look thick, they do not magnify or minify your eyes when seen by others, and they are lighter.