Another source of sunglasses is that it has nothing to do with glasses. These "archaeologists" thought that the earliest "sunglasses" were in today's prehistoric civilization. The Inuit people wore a flat "eyes", which were made of walrus teeth, and the Inuit were slender. The outer surface of the tooth dug out two holes, and the wearer's field of vision can look into the distance through a narrow slit. Although the things seen are somewhat distorted, it is useful to hinder the illumination of harmful light.