Medical terms commonly used in this study

Bispectral Index (BIS): A calculation based on certain readings of an EEG. Used to measure the hypnotic state / sedation level of a patient.
Choroid: The layer filled with blood vessels that nourishes the retina; part of the uvea
Diabetic retinopathy: Injury to the retina's blood vessels by high blood sugar levels (see explanation from St. Luke's Cataract & Laser Institute)
Drusen: Tiny yellow or white deposits in the retina or optic nerve head
Fovea: The central part of the macula that provides the sharpest vision (see picture from St. Luke's Cataract & Laser Institute) (see also Macula)
Fundus: The interior lining of the eyeball, including the retina, optic disc, and macula; portion of the inner eye that can be seen during an eye examination by looking through the pupil
Glaucoma: Increased quantities of aqueous humor in the eyeball. The increased pressure can damage the optic nerve (see explanation from St. Luke's Cataract & Laser Institute)
Macula: The small, sensitive area of the central retina; provides vision for fine work and reading (see picture from St. Luke's Cataract & Laser Institute) (see also Fovea)
Macular degeneration: Degeneration of the tissue of the macula / central retina (see explanation from St. Luke's Cataract & Laser Institute)
Optic cup: The white, cup-like area in the center of the optic disc
Optic disk / optic nerve head: The circular area (disc) where the optic nerve connects to the retina
Retinal pigment epithelium: The pigment cell layer that nourishes the retinal cells; located just outside the retina and attached to the choroid
Sclera: The tough, white, outer layer (coat) of the eyeball; with the cornea, it protects the entire eyeball

Resources on the structure of the Eye

AAO: The web site for the American Academy of Ophthalmology
International Foundation for Optic Nerve Disease: "Dedicated to the promotion of research into the causes, prevention, and treatment of optic nerve disease, and to the dissemination of information about optic nerve disease"
National Eye Institute: A facility of the National Institutes of Health
University of Iowa, Department of Ophthalmology and Visual Sciences: Contains a nice explanation of Ischemic Optic Neuropathy