Every Thursday, a new episode of Living Planet brings you environment stories from around the world, digging deeper into topics that touch our lives every day. The prize-winning, weekly half-hour radio magazine and podcast is produced by Deutsche Welle, Germany's international broadcaster - visit dw.com/environment for more.
It seems like glasses would be the obvious eco-friendly choice, but not so fast! The answer is both fascinating and a bit mind boggling. Get ready for some eye-opening facts that could make you rethink your eyewear habits.