Who first understood how eyes work?
Updated: Feb 26
Some 2,400 years ago the Greek philosopher Plato believed that beams of light emitting from the eyes enabled us to see.  One of his pupils, Aristotle, thought that our eyes and the air were part of a common medium which enabled us to sense the world around us.
Plato's extramission theory. A smooth, gentle "fire" is emitted by the eye and fuses with ambient light to form a sentient "body of vision". The idea for this and the following figures came from Grüsser, 19XX.
Other theories have abounded over the years; all seeking to understand how our eyes help us to translate and interpret our surroundings. And whilst magnifying glasses and lenses came into being relatively early, it was not until the early 1600s that a better understanding of how our eyes work started to emerge.
In 1604 German astronomer Johannes Kepler published a work entitled “Astronomiae Pars Optica.” The central theme of the book looked to follow up on his earlier work on planetary motion by exploring how we could use an understanding of light to explain astronomical phenomena. But in the book he also described for the first time the part played in vision by the retina and the way in which images are inverted in the eye.
Interestingly Kepler was also the first to provide an explanation of how glasses worked, leading him to be widely regarded as the father of modern optics. It may have taken some 541 million years since the first eyes were formed but Kepler enabled us to see how our eyes work.
We're inspired by Kepler's work and the work of countless scientists, astronomers, and engineers who have advanced the use of modern optics. We hope that our work can have as big an impact as theirs. 'We're standing on the shoulders of giants', as the saying goes.