A lens is an optical device that controls the focus of light rays and makes objects look larger than they are to the eye. A Minoan rock crystal hand lens dating back to 2000 B.C. kept in the Archaeological Museum in Heraklion, Crete testifies that ancient peoples including the Egyptians, Greeks and Romans knew about the ability of the lens to converge light to a focus. This old and simple device changed human existence, and particularly the lives of people who have trouble seeing clearly. Lenses are today fixed to frames that come in a variety of designs and colours that can match the shape of the face, mood and lifestyle of the person who is wearing them. Eyeglass frames, however, are a comparatively new invention. Read this article to find out how people kept lenses in front of their face before frames were developed.