ABSTRACT
This chapter reviews various aspects of human visual physiology salient to how we perceive images, whether radiological or artistic in nature. It provides a flavour of the complexity of cerebral mechanisms related to vision by considering several phenomena/conditions. The first entity light encounters as it strikes the visual system of an observing human is a thin layer of tears on the surface of the eye. Light that strikes the cornea perpendicular to its surface is not refracted, so our beam of light does not deviate from its original course, but the cornea also serves to filter out ultraviolet light so absorbs much of the UV component as it passes through. The lens itself is a biconvex encapsulated structure with a high content of crystallin proteins which offer a high level of transparency and refractility.
