[Textual research on history of glasses].

Early glasses is nothing but a single piece of glass without a frame. The latter originating from the "Reading stone" was a long one. It was both aided and retarded by social condition style, quality of available materials and technology. It is reasonable to make a few conclusions about the invention along the line suggested by Rosen; most likely, the inventor was a lay person of Pisa who wished to keep the manufacturing processes a secret in order to make a profit, the date of the invention is most likely around 1270 - 1280. The inventor was by two missionaries of St. Catherine's Friar dirdano da Rivolta and Alessando Spina. Lastly, the author advocates the use of CR-39, based on the following reasons: a high resin plastic, fragile resistance, high refractive index, light weight, and resistance to fogging.