When and how were prescription lenses born?

The foundation of modern optics can be attributed to the Arab astronomer Ibn al-Heitam (ca. 965-1040 AD) who in that period questioned the theories on nature and on the diffusion of the visual images of the time.

His revolutionary studies on images, on the reflection of light on mirrors and on glass and the attempt to understand the functioning of horny human, they gave him many problems, to the point that he had to pretend to be mad in order not to incur serious personal consequences.

Despite this, he continued his studies which he summarized, among others, in the "book of optics" which remained unknown to us until the 13th century, when the monks translated this and his other books into Latin, immediately arousing great sensation and interest.

Before the fourteenth century, vision defects that were congenital, such as myopia, or related to age, caused irreparable limitations.

The first to realize what an incredible discovery they had in their hands were the monks, who were aware of the sight problems that could afflict man especially when they dedicated to the translation of manuscripts and to the conservation and dissemination of knowledge.

The monks invented the first “reading stone”, a convex glass lens that was able to magnify images giving a great relief to those who had visual deficiencies.

There is a transcription of a sermon, made during a religious ceremony in Florence by a Dominican friar to the population, which can be dated around 1306, in which the invention of lenses and the first glasses was mentioned.

Another monk, in Pisa, Alessandro della Spina, in 1313 spoke extensively about the invention and production of eyeglasses, with lenses that corrected visual defects that afflicted the elderly and young people of the time.

At the end of the 13th century the Murano glassworks were able to create the first completely transparent lenses, setting them in small circles of wood or bone, thus creating the first mass production of eyewear.

For a long time glasses had to be held in front of the eyes with one hand, because the way to place them autonomously on people's faces had not yet been found.

Thus the diffusion of lenses for the visual defects of elderly people was rapid and unexpected, as we can see from Petrarch's statements in which he tells us that, having reached 60 years, he had lost his good eyesight and was forced to get help from the new lenses.

In the following century, lenses "for young people" that corrected myopia were also developed, as reported in a letter from 1462, in which he wrote in the Duke of Milan who had equipped himself with lenses to be able to see well from afar.

Glasses no longer became just a tool for reading and writing, but were used all day to correct the visual impairment caused by myopia.

We began to study how to independently support the glasses without having to hold them in hand, coming to think of special hats with lenses incorporated or ad rubber bands placed around the head.

But it was only in the 18th century that the temples of glasses were invented, creating a comfortable and practical way to wear glasses.

For many centuries lenses were produced exclusively in glass but, starting with the discovery of plastic materials, in the last century, they began to be produced with synthetic materials.

The lenses or sunglasses, with plastic materials, proved to be of great comfort and effectiveness as they were much more resistant than glass, much lighter and more economic.

On the other hand, plastic lenses could be thicker than glass ones and easier to scratch and therefore not recommended in certain conditions of use.

Automatic translation. We apologize for any inaccuracies. Original article in Italian.