Well, first, you should know that early sunglasses are used for a special purpose and it wasn't to block the rays of the sun. According to some references, it wasn't until the 20th century that modern-type sunglasses came to be. In 1929, Sam Foster, founder of the Foster Grant company sold the first pair of Foster Grant sunglasses on the Boardwalk in Atlantic City, NJ. So we can say that Sam foster invented sunglasses at that time. And nowadays, sunglasses are wildly used in many places. And they have different types and different functions. And basically, they are polarized and have uv protection. So they can protect your eyes from sunlight and uv rays.