The Polycarbonate, a synthetic plastic material, is known for its high impact resistance, almost bullet proof resistant at point blank range. The impact resistance makes this lens highly preferred for sports wear, children’s wear and safety wear. Polycarbonate lenses are used for astronaut helmet shields and space shuttle windshields. Weighing only 35 percent of the plastic lens, it is one of the lightest ophthalmic materials. The in built protection properties offer 100% ultra violet blocking to about 400 nanometers.