Polarized sunglasses, like many great inventions, are worn by many of us without a second thought. But have you ever stopped to think where polarized sunglasses come from? Someone had to come with them.

Actually, we owe the creation of polarized sunglasses to four men. In the 1750s, James Ayscough experimented with the use of tinted glass to correct vision problems.

Many scientists at the time were studying the properties of light and color. In 1808, Etienne-Louis Malus, a French physicist and mathematician, discovered that light waves from the sun, which normally vibrate in all directions, can be aligned in one direction when reflected from something, such as water. According to Malus’s law, the intensity of light transmitted through a polarizing filter depends on the angle of the filter in relation to the light.

While Malus’s law is important in the study of optics, it was left to the Scottish physicist, astronomer, and inventor Sir David Brewster to discover the angle at which light with a particular polarization can be transmitted across a surface without reflection. He did this in the year 1815. The angle, called the Brewster angle or angle of polarization, is central to the invention of polarized sunglasses.

Throughout the 19th and early 20th centuries, experiments continued. People started wearing yellow or brown colored sunglasses to counter light sensitivity. People realized that color had something to do with polarization. The optical company Bausch & Lomb began producing a dark green glass to protect US Army Air Corps pilots from glare at high altitude.

However, it wasn’t until 1936 that Edwin H. Land, an American inventor, created a polarizing light filter that was lightweight and inexpensive enough for use in sunglasses. He later created the Polaroid Corporation and developed many inventions, including the Land camera, which allowed amateur photographers to see their images unfold instantly.

Land’s invention was quickly put to use in sunglasses produced by Ray-Ban, a unit of Bausch & Lomb. Ray-Ban also created the distinctive “aviator” frame that shielded a pilot’s eyes as he repeatedly looked down at his instrument panel. Army pilots received these glasses for free, and as their popularity grew, Ray Ban soon began selling them to the public. Polarized sunglasses helped pilots see and complete their missions safely. Their ultra-modern and effective goggles added to the pilot’s mystique and soon they were wanted by everyone to imitate their heroes.

Polarized sunglasses are a fashion trend that continues to serve a useful purpose.