This fourth volume in the series Lectures in Optics provides comprehensive coverage of Visual Optics, which is the field of optics as applied to the function of the eye, a magnificent and highly complicated optical system. The optics part of vision in a 'well-performing' eye pertains to the effects responsible for formation and initial detection of the retinal image―the picture of the world as it is projected onto the photosensitive layer of the eye, the retina. The book presents the necessary concepts and definitions that explain retinal image properties, including aspects such as visual acuity and color perception. It discusses the optics of the eye in the presence of refractive errors such as myopia, hyperopia, and astigmatism, certain limitations to vision such as accommodation and near vision, and effects of aging on vision such as presbyopia and low vision. Finally, chapters devoted to ophthalmic optics and prismatic effects provide in-depth coverage of the optics involved in the correction of refractive vision disorders.