| Pupil | Dark opening of the eye where light passes through |
| Iris | Muscle around the pupil that controls the amount of light that enters the pupil |
| Cornea | Transparent layer of tissue that covers the anterior eyeball |
| Lens | Transparent, biconvex structure behind the pupil |
| Anterior Chamber | Portion of the eyeball between the cornea and iris |
| Ciliary Body | Muscle on each side of the lens that adjusts the shape of the lens |
| Vitreous Chamber | Area behind the lens containing a jelly-like fluid called vitreous humor |
| Sclera | The white, outer coat of the eyeball |
| Choroid | Middle, vascular coat of the eyeball |
| Retina | Light-sensitive innermost layer of the eyeball |
| Macula | Small, yellowish area above the optic disk containing the fovea centralis |
| Optic Disk | Commonly called the "Blind Spot", portion where the retina meets the optic nerve |
| Optic Nerve | Cranial nerve that carries impulses from the eye to the brain |
| Aqueous Humor | Thin, watery fluid produced by the ciliary body; used to nourish the lens and maintain ocular pressure |
| Canthus | Corner of the eye |
| Cones | Photoreceptor cells of the retina responsible for color and central vision |
| Conjuctiva | Thin, delicate mucous membrane lining the eyelids and anterior eyeball |
| Macula | Small, yellowish area above the optic disk containing the fovea centralis |
| Nictitating Membrane | Third eyelid, protects the eye |
| Orbit | Bony cavity of the skull containing the eyeball |
| Palpebra | Eyelid |
| Rods | Photoreceptor cells of the retina responsible for night and peripheral vision |
| Tapetum Lucidum | Iridescent layer of epithelium that gives the eye the property of shining in the dark; helps improve night vision |
| Uvea | Vascular layer of the eye |
| Vitreous Humor | Clear, jelly-like fluid in the vitreous chamber that gives the eyeball its shape |
| Anopthalmus | Congenital anomaly in which the animal lacks one or both eyes |
| Cataract | Clouding of the lens leading to decreased vision |
| Ectropion | Turning outward of the eyelid |
| Entropion | Turning inward of the eyelid |
| Enucleation | Removal of the eyeball |
| Esotropia | Cross-eyed |
| Exopthalmus | Forward protrusion of the eyeballs |
| Exotropia | Deviation of one eye outward |
| Floaters | Particles in the vitreous fluid that cast shadows on the retina |
| Glaucoma | Increased intraocular pressure resulting in damage to the eye |
| Hypertropia | Condition in which one eye deviates upward |
| Hypotropia | Condition in which one eye deviates downward |
| Miosis | Abnormal contractions of the pupils |
| Mydriasis | Abnormal dilation of the pupils |
| Nuclear Sclerosis | Drying out of the lens with age |
| Nystagmus | Rhythmic, rapid, back-and-forth movement of the eyes |
| Palpebral Reflex | Blink reflex when the eyelids are touched |
| Photophobia | Sensitivity or visual intolerance to light |
| Proptosis | Forward displacement of the eye from its orbit |
| Tonometer | Instrument to measure intraocular pressure |
| Tonometry | Measurement of intraocular pressure |
| Auricle | Flap of the ear |
| Cerumen | Waxy substance secreted by the sebaceous glands in the auditory canal |
| Cochlea | Spiral, snail-shaped tube in the inner ear containing fluid that is essential for hearing |
| Endolymph | Fluid within the inner ear |
| Eustachian Tube | Channel that connects the middle ear to the pharynx |
| Incus | Second ossicle of the inner ear |
| Labyrinth | Maze-like structure of the inner ear |
| Organ of Corti | Sensitive receptor area in the cochlea |
| Ossicles | Small bones of the middle ear |
| Semicircular Canals | Three tubes of the inner ear used to maintain equilibrium |
| Stapes | Third ossicle of the inner ear |
| Tympanic Membrane | Eardrum; Membrane between the outer and middle ear |
| Aural Hematoma | Mass of blood in the ear flap |
| Otitis Externa | Inflammation of the external ear |
| Otitis Media | Inflammation of the middle ear |
| Otitis Interna | Inflammation of the inner ear |
| Vertigo | Sense of dizziness |
