History of Spectacle Lenses

Spectacles might be one of the most useful objects of our daily life; but surprisingly the circumstances of its invention remain quite unclear.

Part 1. The Antiquity (700 BC - 400 AD)

The interest for optics started a long time ago, in the Antiquity. The earliest known lenses were found among the rest of the Egyptian and Mesopotamian civilizations. The lenses were made of polished crystal, mainly quartz, and were used as a magnifying glass or burning glass to start fire by concentrating the sun’s rays on a small area, or to erase writings on wax tablets. The oldest lens is called the “Nimrud Lens”. Belonging to the Assyrian civilization, this lens is 3000 years old.

Theories of optics were developed by trial and error by the Greco-Roman philosophers. Plato elaborated the emission theory, which proposed that visual perception is due to rays emitted by our eyes. Later, Euclid studied optics from a mathematical point of view. These ideas developed at that time were later extended by Muslim savants, such as Alhazen. Many manuscripts refer to the use of stone and crystal. As far as we know, the Roman Emperor Nero was using an emerald to better see the gladiators’ fights.

Read Part 2: Spectacle Lenses in The MIddle Ages