The evolution of the reading glass frame has a history of its own. The oldest spectacles, known to us from a painting by di Modena in 1352, consisted of two lenses in rims, joined centrally. The inconvenience of holding such glasses in position for any length of time led to a modification suggesting sugar-tongs. Metal rims gave way to leather ones.  Such a pair has been found preserved within a book. An early modification, incidentally recommended by Savodarola, was to secure the glasses by a tape tucked under the hat, a method rather reminiscent of the Chinese way of binding the glasses to the head gear.  Various forms of lorgnette followed.

The original attempts at ear-rails added greatly to the already heavy weight of spectacles. It was only towards the end of the 18th century that passable ear-rails came to be introduced. These were followed by glasses with nose-pieces having a spring, a marked advance on the much earlier nose-riders which were kept in position by the pressure the rims exercised on the nose. Gold, silver, steel, fish-bone, horn, wood and leather have all been used for the making of the spectacle frame. 

4readers.com