PC lens, also known as "space film", because of its excellent impact resistance, it also has a commonly known as bullet-proof glass. Polycarbonate lenses are highly resistant to impact, won’t shatter. They are 10 times stronger than glass or standard plastic, making them ideal for children, safety lenses, and outdoor activity. Progressive lenses, sometimes called "no-line bifocals," eliminate the visible lines of traditional bifocals and trifocals and hide the fact that you need reading glasses. Tags: bifocal lens,progressive lens,1.56 pc lens