This paper presents Kepler's theory of the process of vision, exposed in fifth book of Paralipomena, published in 1604. We pointed the following aspects: (1) the catalogue of the human eye made by Kepler, that was founded in Felix Plater's anatomical works; (2) the analogy between the obscure chamber and the human eye, with the understanding that the former is a dioptrical instrument like the last one; (3) the correct use, following Kepler, of geometry to the anatomical-physiological constitution exposed in the Paralipomena. From these elements, Kepler treats two basic points for the optic in the xvii th century: the first affirms that the image of the object seen by the eye is formed in the retina and not in the crystalline; the second restricts the realm of optical studies only to that treated through optical components, that is to say, to anatomical and physiological constituents, and their possibilities of geometrization.
Optic; Kepler; Anatomy; Physiology; Plater; Alhazen; Retina; Crystalline