In this chapter you will learn
 

• The structure of the eye
• How the eye begins processing visual information even before it is sent to the brain
• The major theories of color and form vision
• How color, form, movement, and spatial location are handled in the brain
• Some of the visual disorders caused by brain damage and what they tell us about brain function

To complement the review of audition and language presented in Chapter 9, Chapter 10 discusses the mechanisms involved in vision and visual perception. The chapter begins with a description of the visible spectrum and the eye and its receptors. Particular attention is given to the neural pathways of visual information from the retina to the cortex, including how information from each side of the visual field projects to the opposite hemisphere. Next, color vision is addressed, beginning with two earlier foundational theories, followed by a more modern theory combining the two. Knowledge of the receptor mechanisms is used to explain common forms of color vision deficiency. Next, the major aspects of visual perception are explained. Form vision is discussed in terms of two competing theories of edge detection. The chapter concludes with the perception of objects, color, and movement. The ventral and dorsal streams, consisting primarily of the parvocellular and magnocellular systems, are described in the context of several perceptual disorders. The chapter concludes with the problem of final integration, namely that no mechanism has been discovered that integrates the mass of visual information into a unified perception. Two Applications describe cutting edge treatments to restore vision and synesthesia, treated as a case of binding gone too far.