Contact Lens

A transparent disc that corrects vision from 1 cm away/Medicine & Biology

A modern soft contact lens is about 14 mm in diameter and just 0.06-0.1 mm thick at the center. It sits on the tear film of the eye, not directly on the cornea. Leonardo da Vinci sketched the concept of contact lenses in 1508, but practical lenses were not developed until the 1950s. About 150 million people worldwide wear contact lenses. Each one must allow oxygen to pass through to keep the cornea healthy.