CORNEA: Transparent front segment of the eye that covers iris, pupil, and anterior chamber, and provides most of an eye’s optical power.
PUPIL: Variable-sized, circular opening in center of iris; it appears as a black circle and it regulates the amount of light that enters the eye.
IRIS: Pigmented tissue lying behind cornea that (1) gives color to the eye, and (2) controls amount of light entering the eye by varying size of black pupillary opening; separates the anterior chamber from the posterior chamber.
LENS: Natural lens of eye; transparent intraocular tissue that helps bring rays of light to focus on the retina.
RETINA: Part of the eye that converts what we see into electrical impulses sent along the optic nerve for transmission back to the brain. Consists of many named layers that include rods and cones.
MACULA: Small, specialized central area of the retina responsible for the sharpest central vision.
VITREOUS: Transparent, colorless, gelatinous filling; in the rear two-thirds of the interior of the eyeball, between the lens and the retina.
OPTIC NERVE: Largest sensory nerve of the eye; carries impulses for sight from retina to brain.
SCLERA: The white of the eye; a protective fibrous layer that is the outer covering of the eyeball except for the part that is the cornea.
CILIARY BODY: The part of the eye consisting of the ciliary muscle (which alters the curvature of the lens), a series of radial ciliary processes (from which the lens is suspended by ligaments), and the ciliary ring (which adjoins the choroid).