Visual sensation and visual perception are the processes by which we see and understand our surroundings. The difference between these processes and the dividing line where sensation ends and perception begins is debatable, however some distinctions can be made. Sensation is a physiological function, and begins with reception, when the cornea and lens of the eye focus light on the photoreceptors (rods and cones) in the retina of the eye. After this, transduction occurs, transforming stimulus energy into nerve impulses. The next step is transmission, which is the movement of the data in the form of nerve impulses from the receptors to the brain. As sensation is physiological, all