The use of sunglasses goes back to before the 12th Century, it even goes as far back as the Inuit tribes, who wore walrus ivory glasses with narrow slits cut out to reduce the intake of light, technically not sunglasses but it shows that it was a problem back in the day, and still persists.
It was in the 19th century when the use of sunglasses started to take shape, movie stars were using them to avoid recognition when out and about, and it follows on that, what movie stars we start to adopt as well. The sunglasses did not become available to the mass market till 1929 when an entrepreneurial Sam Foster started selling his new Sunglasses to the people on the Boardwalk. ?The now legendary Polarised lenses arrived in 1936 when Polaroid where experimenting with their new patented Polaroid filters, at this time the armed Forces were recognising the need for Sunglasses especially for Aircraft Pilots and the Navy.
At this time Ray-Ban were just starting to produce sunglasses and the Aviator had been adopted by the Armed Forces and Emergency services as the sunglass of choice, along came the war and the explosion of Aviation and everyone was soon wearing Ray-Ban Sunglasses. The UV filter is the most important part in the make-up in any pair of sunglasses, and it brands like Ray-Ban have an unwavering attention to detail and quality, with the lenses tested to destruction and the Polarised lenses on a pair of Ray-Ban really do make a big difference on a sunny day.
With lenses, it is not just cosmetic, there are actual differences with the colour of lens used.