Thick One Piece Shatterproof Polycarbonate Lens. Polycarbonate lenses are thinner and lighter than standard plastic varieties, and also much more durable. Polycarbonate is ideal for strong prescriptions because it corrects vision without adding thickness, which can distort the wearer's appearance. Best of all, polycarbonate lenses are virtually unbreakable, making them a great choice for children and active adults.