More than 30 million people in the U.S. wear contact lenses. But as this 1948 newsreel footage shows, today's common vision corrective was once a novel and strange medical device.

The newsreel, which British Pathé recently unearthed, opens with a close-up shot of a woman without glasses. "This girl is wearing glasses," a narrator says—but of course, she's wearing contact lenses. With the cheery speed typical of mid-century newsreels, the narrator describes how the lenses were made: the eye is anesthetized, then the optician—a man named Penrhyn Thomas, who was apparently Australia's only contact lens maker—uses an "impression cup" to make a cast of the eyeball.

Warning: anyone squeamish about things touching eyeballs shouldn't watch…most of the video.

After two minutes, Thomas removes the cup from her eyeball. The mold is used to shape a piece of flexible plastic, which experts then grind and polish so the lens fits an exact prescription.

The idea behind contact lenses dates all the way back to Leonardo da Vinci, writes Rachel Swaby for Gizmodo. In a 1509 manual, da Vinci noted that he could alter his vision by sticking his face in a bowl of water. During the next few centuries, Swaby explains, inventors sketched ideas such as "tubes held snug to the eyelids" and "capsules filled with animal jelly," but the contact lens wasn't actually manufactured until 1887.

At that time, German ophthalmologist Adolph Fick placed glass shells on the eyes of rabbits. Rather than correct vision, Fick hoped his technique could treat keratoconus, a condition causes the cornea to bulge. Eventually, Fick tried fitting the lenses on himself and other human volunteers. These devices fit across the entire eye and could only be worn a few hours at a time, according to London's Science Museum.

The invention of polymethyl methacrylate — and plastic lenses —brought greater relief in the 1930s. (The Smithsonian's American History Museum has a pair of these early plastic lenses in its collection.) In 1948, Swaby writes, optical technician Kevin Tuohy developed a smaller lens that only covered the cornea, which allowed people to wear lenses for longer periods of time. Further innovation came from Czech chemists Otto Wichterle and Drashoslav Lím, who invented the breathable plastic material that led to soft lenses in the 1960s.

Now, humans are free to advance this invention in other ways: in the future, augmented reality contact lenses may replace your phone.

(h/t Jason Kottke)