Before sunglasses were considered a fashion accessory, they were more of a tool – functional and practical.
During World War I, advancement of technology in flight systems meant pilots needed to fly higher, and for longer periods of time. Hence they were often exposed to the sun in closer proximity, and at the same time dealing with sub-zero temperatures. These pilots often returned from flights with very exhausted eyes. Aviators were invented to counteract this problem. With the teardrop shaped lenses that fully covered the eye socket, it became a military essential.
Fast forward to the 80s, the movie Top Gun was released. This movie catapulted actor Tom Cruise to fame, together with the iconic Aviator that he wore throughout most parts of the movie.