These are some of the first recorded "sunglasses". These are of Inuit invention, a group of people who know all to well the dangers of harsh reflected light. Ice and snow are some of the most reflective surfaces and can pose serious dangers for the human eye, which is not equipped to see in that bright of light. Read more about Snow-blindness here.
This design is tried and true but if you are looking for more contemporary styles FYidoctors sells prescription and non-prescription sunglasses. Find a location near you.