Extraordinary Eyeglasses: The Amazing Invention That Helps Us See

So many of us wear glasses. They help us read, work and play. They are for the young and old, for bookworms and professional athletes, and are used by people in every country around the world.

Learn how glasses bend light and what color blindness really means. How tears work and why we have eyelids. Learn all about the human eye, and about the extraordinary vision of cats, birds and flies. Take a tour through the long history of eyeglasses...