The visual field refers to the total area in which objects can be seen in the side (peripheral) vision when the eyes are focused on a central point. Glaucoma is a condition of the eye in which the optic nerve is damaged due to increased fluid pressure in the eye. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness. A visual field test is a method of measuring an individual's entire scope of vision, that is their central and peripheral (side) vision. The test is most frequently used to help detect glaucoma but may also be used for detection of central or peripheral diseases of the retina, eyelid conditions such as drooping (ptosis), optic nerve damage and disease, and conditions affecting the visual pathways from the optic nerve to the area of the brain (occipital cortex) where this information is processed into vision. The fourth edition of this comprehensive text provides ophthalmologists and trainees with a guide to the interpretation of visual field tests and subsequent diagnosis and management of ocular disorders. The book has been fully revised and features additional topics including two new classification systems for glaucoma. Nearly 800 clinical photographs and diagrams further enhance learning.