The renewed interest in optics and advances in the manufacture of glass allowed that at the end of the thirteenth century a monk created the first proper glasses of History
Before the fourteenth century, vision defects, whether congenital, such as myopia, or linked to age, were an irremediable limitation. This affected above all those who engaged in precision work or intellectual activities based on reading and writing. Among the latter were the monks, for centuries the great conservatives of Western knowledge. Therefore, it is not strange that it was in a convent where shortly before 1300 an invention was developed that since then has changed the life of a considerable part of humanity: the glasses.
An Arab scientist, Ibn al-Haytham, known in Europe as Alhacen, created in the eleventh century the theoretical basis for this invention with his study of the human cornea and the effects of light rays on mirrors and lenses. His books were translated into Latin in the thirteenth century and fed a widespread interest in optics and its practical applications. Thus appeared the «reading stones», planoconvex (semi-spherical) lenses that were used as magnifying glasses and that constitute the precedent of glasses.
In 1306, a Dominican said in a sermon in Florence: «It has not been twenty years since the art of making glasses was found, which make it look good, which is one of the best and most necessary arts that the world has, and so recently that he met […] I saw the one who first found and did it, and I spoke with him. » Therefore, the invention is placed around 1286. Another of the time mentions a monk from Pisa named Alessandro della Spina, who died in 1313, who «was able to redo everything he saw. devised before, but without wanting to communicate his secret, Alessandro, on the other hand, taught everyone how to do it «.
For adults and young people
These first glasses consisted of two lenses mounted in circles of wood or antler, joined by a rivet and placed on the nose. The lenses, biconvex type, solved the defects in near vision, such as presbyopia. There are references to the use of transparent quartz material or crystal of another precious stone, beryl, although the first glasses have also been linked to the technique of making glass based on sand, potassium and sodium carbonate, developed in Byzantium and adopted by the Venetians.
The glasses quickly became widespread among the elderly. For example, the poet Petrarca remembered how around 1350, when he was 60 years old, he suddenly lost his good eyesight and was «forced to reluctantly resort to the help of glasses». In the fifteenth century a new type of glasses appeared, «suitable for distant vision, that is, for young people», as the Duke of Milan said in a letter of 1462, in a clear reference to concave lenses that correct myopia .
This last type of glasses were not only useful for specific tasks such as reading and writing, but they could be worn all the time. And perhaps this caused more attention to be paid to the problem of how to hold the glasses on the nose without having to put up with the hand, as was the case at the beginning. For example, hats were proposed with wires from which the glasses hung, or a leather band that held the lenses around the head. Curiously, the method of the whiskers (first pressing the temples and then fastened to the ears) did not spread until the eighteenth century. It was then that the glasses, comfortable to wear, relatively cheap (thanks to their industrial production) and with lenses increasingly adapted to the needs of each, became for many an irreplaceable appendix to move around the world.