From the newspapers in which the stars wearing the round lenses sunglasses, we find that it becomes the fashionable trend. It is the last century rock father John lennon that leads the fashion of round glasses. It has been a tide over the fashion of the vintage style. You may see many stars wearing the round sunglasses in front of media.
It is really hard to say that who start the trend of round sunglasses as round is the most immemorial shape of glasses lens. The first lens which is made by Leeuwenhoek, the inventor of lens is just round and the original shape doesn't change for centuries. Especially in the first one or two decades of 20th century, sunglasses begin to sweep the world. Round dark sunglasses seem to be the most classical type. Of cause, referring to a fashion trend, a scientist is not proper as a reference. As for who bring round sunglasses back to fashion, the most well known character come into my mind is Harry Potter. The round glasses he wears in the movie make the old fashioned glasses fresh to the world. It looks gentle, scholarly and wise. As the movie comes out, round glasses, and the derivation round sunglasses becomes popular, especially among males.