His eye-deficiency seems the most perfidious trick that fate could inflict on a stargazer; but how is one to decide whether an inborn affliction will paralyse or galvanize? The myopic child, who sometimes saw the world doubled or quadrupled, became the founder of modern optics (the word ‘dioptries’ on the oculist’s prescription is derived from the title of one of Kepler’s books); the man who could only see clearly at a short distance, invented the modern astronomical telescope.
