Sunglasses not only protect your eyes from those harmful UV rays, but they’re also an iconic fashion statement piece. And, in these blazing summer months, you couldn’t be more grateful for these little accessories which allow you to avoid having to squint and cover your eyes during sunny afternoons. But do you know how your sunglasses are made or how sunglasses became so popular?

Brief History of Sunglasses 

The earliest sunglasses we know of date back to prehistoric times when Inuit people used flattened walrus ivory with a slit to protect their eyes against snow blindness. Fast forward to 1 AD when Romans watched gladiator fights through gemstones while in the twelfth century, the Chinese made sunglasses out of smoky quartz to protect their eyes from glare. Ancient Chinese judges even used them to hide their facial expressions when they interrogated witnesses (similar to how modern-day poker players often wear sunglasses). 

However, glasses as we know them today didn’t come about until the 1700s when English optician James Ayscough developed green-tinted lenses to correct some vision impairments. These tinted glasses were further prescribed in the 1800s for people with syphilis because one of the disease’s symptoms is sensitivity to light.

Mass-produced sunglasses to protect consumers from the sun’s rays were made by Sam Foster in 1929, becoming popular with actors and actresses who wanted to protect their eyes from the bright lights and camera flashes of movie sets. These were made with Crookes lenses which contained cerium in its glass, blocking ultraviolet light. Foster began selling his sunglasses on the boardwalk of Atlantic City to protect eyes from the sun, thus beginning the sunglasses craze that we still see today.

How Are Sunglasses Made?

1. Start with the Frames

When making sunglasses, you must start with the frames first. A steel mold is built to mimic the desired shape of the frames. Next, cellulose-acetate (a plastic material) is made into sheets that are slightly wider than the frames. These sheets are heated in an oven until they’ve become malleable and then they’re punched with the steel mold to create the frame shape. Once they’ve been removed from the sheet, the lens portions of the frames are also removed. The grooves for the lenses are then cut using a router blade and the frames are smoothed using different machines for the nose and cheek areas.

2. Make Temples For the Glasses

Next, the sunglasses’ temples are made. The same plastic material as earlier (cellulose-acetate) is melted in an oven in thin sheets. Blank templates are punched through the sheets using a steel die. Those templates are then heated, and a strip of steel core wire is inserted in the center. A machine then cuts slots into the side of the temples and the hinges are placed and secured using heat.

3. Create The Lenses

The final step in making sunglasses involves creating the lenses. When it comes to sunglass lenses, you first start by adding the colorant. This is done by either adding color to the molten lens material initially or with a chemical coating on a finished lens. Regardless of which is chosen, molten plastic is cast into a mold that creates the basic lens shape (either round, square, cat eye, etc). The lens is then sent to a machine called the curve generator which shaves a curve into the back. Next, an edge grinder is used to further shave the outer shape of the lens into the desired shape. Finally, the lenses are coated with an anti-reflective material and are mechanically snapped into the groves of the frame.