Term | Definition |
equilibrium | The sense of balance |
gustation | The sense of taste (Latin geusis means "taste") |
hearing | The sense or perception of sound |
olfaction | The sense of smell (root osm/o means "smell") |
proprioception | The awareness of posture, movement, and changes in equilibrium; receptors are located in muscles, tendons, and joints |
sensory receptor | A sensory nerve ending or a specialized structure associated with a sensory nerve that responds to a stimulus |
tactile | Pertaining to the sense of touch |
vision | The sense by which the shape, size, and color of objects are perceived by means of the light they give off |
-esthesia | sensation |
-algesia | pain |
-osmia | sense of smell |
-geusia | sense of taste |
auditory tube | The tube that connects the middle ear with the nasopharynx and serves to equalize pressure between the outer and middle ear (root: salping/o); pharyngotympanic tube; originally called the eustachian tube |
cerumen | The brownish, wax-like secretion formed in the external ear canal to protect the ear and prevent infection (adjective: ceruminous) |
cochlea | The coiled portion of the inner ear that contains the receptors for hearing (root: cochle/o) |
external auditory canal | Tube that extends from the pinna of the ear to the tympanic membrane; eternal auditory meatus |
incus | The middle ossicle of the ear |
labyrinth | The inner ear, named for its complex structure, which resembles a maze |
malleus | The ossicle of the middle ear that is in contact with the tympanic membrane and the incus |
ossicles | The small bones of the middle ear; the malleus, incus, and stapes |
pinna | The projecting part of the outer ear; auricle |
semicircular canals | The three curved channels of the inner ear that hold receptors for equilibrium |
spiral organ | The hearing receptor, which is located in the cochlea of the inner ear; organ of Corti |
stapes | The ossicle that is in contact with the inner ear (roots: staped/o, stapedi/o) |
tympanic membrane | The membrane between the external auditory canal and the middle ear (tympanic cavity); the eardrum; it serves to transmit sound waves to the ossicles of the middle ear (roots: myring/o, tympan/o) |
vestibular apparatus | The portion of the inner ear that is concerned with the sense of equilibrium; it consists of the vestibule and the semicircular canals (root: vestibul/o) |
vestibule | The chamber in the inner ear that holds some of the receptors for equilibrium |
vestibulocochlear nerve | The nerve that transmits impulses for hearing and equilibrium from the ear to the brain; eighth cranial nerve; auditory or acoustic nerve |
audi/o | hearing |
acous, acus, cus | sound, hearing |
ot/o | ear |
myring/o | tympanic membrane |
tympan/o | tympanic cavity (middle ear), tympanic membrane |
salping/o | tube, auditory tube |
staped/o, stapedi/o | stapes |
labyrinth/o | labyrinth (inner ear) |
vestibul/o | vestibule, vestibular apparatus |
cochle/o | cochlea (of inner ear) |
acoustic neuroma | A tumor of the eighth cranial nerve sheath; although benign, it can press on surrounding tissue and produce symptoms; also called an acoustic or vestibular schwannoma or acoustic neurilemmoma |
conductive hearing loss | Hearing impairment that results from blockage of sound transmission to the inner ear |
Ménière disease | A disease associated with increased fluid pressure in the inner ear and characterized by hearing loss, vertigo, and tinnitus |
otitis externa | Inflammation of the external auditory canal; swimmer's ear |
otitis media | Inflammation of the middle ear with accumulation of serious (watery) or mucoid fluid |
otosclerosis | Formation of abnormal and sometimes hardened bony tissue in the ear; it usually occurs around the oval window and the footplate (base) of the stapes, causing immobilization of the stapes and progressive hearing loss |
sensorineural hearing loss | Hearing impairment that results from damage to the inner ear, eighth cranial nerve, or auditory pathways in the brain |
tinnitus | A sensation of noises, such as ringing or tinkling, in the ear |
vertigo | An illusion of movement, as of the body moving in space or the environment moving about the body; usually caused by disturbances in the vestibular apparatus; used loosely to mean dizziness or lightheadedness |
myringotomy | Surgical incision of the tympanic membrane; performed to drain the middle ear cavity or to insert a tube into the tympanic membrane for drainage |
stapedectomy | Surgical removal of the stapes; it may be combined with insertion of a prosthesis to correct otosclerosis |
aural | Pertaining to or perceived by the ear |
decibel (dB) | A unit for measuring the relative intensity of sound |
hertz (Hz) | A unit for measuring the frequency (pitch) of sound |
mastoid process | A small projection of the temporal bone behind the external auditory canal; it consists of loosely arranged bony material and small, air-filled cavities |
stapedius | A small muscle attached to the stapes; it contracts in the presence of a loud sound, producing the acoustic reflex |
cholesteatoma | A cyst-like mass containing cholesterol that is most common in the middle ear and mastoid region; a possible complication of chronic middle ear infection |
labyrinthitis | Inflammation of the ear's labyrinth (inner ear); otitis interna |
mastoiditis | Inflammation of the air cells of the mastoid process |
presbycusis | Loss of hearing caused by aging presbyacusis |
audiometry | Measurement of hearing |
electronystagmography (ENG) | A method for recording eye movements by means of electrical responses; such movements may reflect vestibular dysfunction |
otorhinolaryngology (ORL) | The branch of medicine that deals with diseases of the ear(s), nose, and throat (ENT); also called otolaryngology (OL) |
otoscope | Instrument for examining the ear |
Rinne test | Test that measures hearing by comparing results of bone conduction and air conduction; bone conduction is tested through the mastoid process behind the ear |
spondee | A two-syllable word with equal stress on each syllable; used in hearing tests; examples are toothbrush, baseball, cowboy, pancake |
Weber test | Test for hearing loss that uses a vibrating tuning fork placed at the center of the head |
ABR | Auditory brainstem response |
AC | Air conduction |
BAEP | Brainstem auditory evoked potentials |
BC | Bone conduction |
dB | Decibel |
ENG | Electronystagmography |
ENT | Ear(s), nose, and throat |
HL | Hearing level |
Hz | Hertz |
OL | Otolaryngology |
OM | Otitis media |
ORL | Otorhinolaryngology |
ST | Speech threshold |
TM | Tympanic membrane |
TTS | Temporary threshold shift |
accommodation | Adjustment of the lens's curvature to allow for vision at various distances |
aqueous humor | Fluid that fills the eye anterior to the lens |
choroid | The dark, vascular, middle layer of the eye (roots: chori/o, choroid/o); part of the uvea |
ciliary body | The muscular portion of the uvea that surrounds the lens and adjusts its shape for near and far vision (root: cycl/o) |
cone | A specialized cell in the retina that responds to light; cones have high visual acuity, function in bright light, and respond to colors |
conjunctiva | The mucous membrane that lines the eyelids and covers the eyeball's anterior surface |
convergence | Coordinated movement of the eyes toward fixation on the same point |
cornea | The clear, anterior portion of the sclera (roots: corne/o, kerat/o) |
fovea | The tiny depression in the retina that is the point of sharpest vision; fovea centralis, central |
iris | The muscular colored ring between the lens and the cornea; regulates the amount of light that enters the eye by altering the size of the pupil at its center (roots: ir, irid/o, irit/o) (plural: irides) |
lacrimal gland | A gland above the eye that produces tears (roots: lacrim/o, dacry/o) |
lens | The transparent, biconvex structure in the anterior portion of the eye that refracts light and functions in accommodation (roots: lent/i, phak/o) |
macula | A small spot or colored area; used alone to mean the yellowish spot in the retina that contains the fovea |
optic disk | The point where the optic nerve joins the retina; at this point, there are no rods or cones; also called the blind spot or optic papilla |
orbit | The bony cavity that contains the eyeball |
palpebra | An eyelid; a protective fold (upper or lower) that closes over the anterior surface of the eye (roots: palpebr/o, blephar/o) (adjective: palpebral) (plural: palpebrae) |
pupil | The opening at the center of the iris (root: pupil/o) |
refraction | The bending of light rays as they pass through the eye to focus on a specific point on the retina; also the determination and correction of ocular refractive errors |
retina | The innermost, light-sensitive layer of the eye; contains the rod and cones, the specialized receptor cells for vision (root: retin/o) |
rod | A specialized cell in the retina that responds to light; rods have low visual acuity, function in dim light, and do not respond to color |
sclera | The tough, white, fibrous outermost layer of the eye; the white of the eye (root: slcer/o) |
uvea | The middle, vascular layer of the eye (root: uve/o); consists of the choroid, ciliary body, and iris |
visual acuity | Sharpness of vision |
vitreous body | The transparent jelly-like mass that fills the eyeball's main cavity; also called vitreous humor |
blephar/o | eyelid |
palpebr/o | eyelid |
dacry/o | tear, lacrimal apparatus |
dacryocyst/o | lacrimal sac |
lacrim/o | tear, lacrimal apparatus |
opt/o | eye, vision |
ocul/o | eye |
ophthalm/o | eye |
scler/o | sclera |
corne/o | cornea |
kerat/o | cornea |
lent/i | lens |
phak/o, phac/o | lens |
uve/o | uvea |
chori/o, choroid/o | choroid |
cycl/o | ciliary body, ciliary muscle |
ir, irit/o, irid/o | iris |
pupill/o | pupil |
retin/o | retina |
-opsia | condition of vision |
-opia | condition of the eye, vision |
age-related macular degeneration (AMD) | Deterioration of the macula associated with aging; macular degeneration impairs central vision |
astigmatism | An error of refraction caused by irregularity in the curvature of the cornea or lens |
cataract | Opacity of the lens of the eye |
conjunctivitis | Inflammation of the conjunctiva; pink eye |
diabetic retinopathy | Degenerative changes in the retina associated with diabetes mellitus |
glaucoma | An eye disease caused by increased intraocular pressure that damages the optic disk and causes vision loss; usually results from faulty fluid drainage from the anterior eye |
hyperopia | A refractive error in which light rays focus behind the retina and objects can be seen clearly only when far from the eye; farsightedness; also called hypermetropia |
myopia | A refractive error in which light rays focus in front of the retina and objects can be seen clearly only when very close to the eye; nearsightedness |
ophthalmia neonatorum | Severe conjunctivitis usually caused by infection with gonococcus during birth |
phacoemulsification | Removal of a cataract by ultrasonic destruction and extraction of the lens |
presbyopia | Changes in the eye that occur with age; the lens loses elasticity and the ability to accommodate for near vision |
retinal detachment | Separation of the retina from its underlying layer |
trachoma | An infection caused by Chlamydia trachomatis leading to inflammation and scarring of the cornea and conjunctiva; a common cause of blindness in underdeveloped countries |
canthus | The angle at either end of the slit between the eyelids |
diopter | A measurement unit for the refractive power of a lens |
emmetropia | The normal condition of the eye in refraction, in which parallel light rays focus exactly on the retina |
fundus | A bottom or base; the region farthest from the opening of a structure; the eye's fundus is the posterior portion of the interior eyeball as seen with an ophthalmoscope |
meibomian gland | A sebaceous gland in the eyelid |
tarsus | The framework of dense connective tissue that gives shape to the eyelid; tarsal plate |
zonule | A system of fibers that holds the lens in place; also called suspensory ligaments |
amblyopia | A condition that occurs when visual acuity is not the same in the two eyes in children (prefix ambly means "dim"); disuse of the poorer eye will result in blindness if not corrected; also called "lazy eye" |
anisocoria | Condition in which the two pupils (root: cor/o) are not of equal size |
blepharoptosis | Drooping of the eyelid |
chalazion | A small mass on the eyelid resulting from the inflammation and blockage of a meibomian gland |
drusen | Small growths that appear as tiny yellowish spots beneath the retina of the eye; typically occur with age but also occur in certain abnormal conditions |
floater | A small moving object in the field of vision that originates in the vitreous body; floaters appear as spots or threads and are caused by benign degenerative or embryonic deposits in the vitreous body that cast a shadow on the retina |
hordeolum | Inflammation of a sebaceous gland of the eyelid; a sty |
keratoconus | Conical protrusion of the corneal center |
miosis | Abnormal contraction of the pupils (from Greek meiosis meaning "diminution") |
mydriasis | Pronounced or abnormal dilation of the pupil |
nyctalopia | Night blindness; inability to see well in dim light or at night (root: nyct/o); often due to lack of vitamin A, which is used to make the pigment needed for vision in dim light |
nystagmus | Rapid, involuntary, rhythmic movements of the eyeball; may occur in neurologic diseases or disorders of the inner ear's vestibular apparatus |
papilledema | Swelling of the optic disk (papilla); choked disk |
phlyctenule | A small blister or nodule on the cornea or conjunctiva |
pseudophakia | A condition in which a cataractous lens has been removed and replaced with a plastic lens implant |
retinitis | Inflammation of the retina; causes include systemic disease, infection, hemorrhage, exposure to light |
retinitis pigmentosa | A hereditary chronic degenerative disease of the retina that begins in early childhood; there is atrophy of the optic nerve and clumping of pigment in the retina |
retinoblastoma | A malignant glioma of the retina; usually appears in early childhood and is sometimes hereditary; fatal if untreated, but current cure rates are high |
scotoma | An area of diminished vision within the visual field |
strabismus | A deviation of the eye in which the visual lines of each eye are not directed to the same object at the same time; also called heterotropia or squint |
synechia | Adhesion of parts, especially adhesion of the iris to the lens and cornea (plural: synechiae) |
xanthoma | A soft, slightly raised, yellowish patch or nodule usually on the eyelids; occurs in the elderly; also called xanthelasma |
canthotomy | Surgical division of a canthus |
cystotome | Instrument for incising the lens capsule |
electroretinography (ERG) | Study of the retina's electrical response to light stimulation |
enucleation | Surgical removal of the eyeball |
gonioscopy | Examination of the angle between the cornea and the iris (anterior chamber angle) in which fluids drain out of the eye (root goni/o means "angle") |
keratometer | An instrument for measuring the curvature of the cornea |
mydriatic | A drug that causes dilation of the pupil |
phorometer | An instrument for determining the degree and kind of strabismus |
retinoscope | An instrument used to determine refractive errors of the eye; also called a skiascope |
slit-lamp biomicroscope | An instrument for examining the eye under magnification |
Snellen chart | A chart printed with letters of decreasing size used to test visual acuity when viewed from a set distance; results reported as a fraction giving a subject's vision compared with normal vision at a distance of 20 feet |
tarsorrhaphy | Suturing together of all or part of the upper and lower eyelids |
tonometer | An instrument used to measure fluid pressure in the eye |
A, Acc | Accommodation |
AMD | Age-related macular degeneration |
ARC | Abnormal retinal correspondence |
As, AST | Astigmatism |
cc | With correction |
Em | Emmetropia |
EOM | Extraocular movement, muscles |
ERG | Electroretinography |
ET | Esotropia |
FC | Finger counting |
HM | Hand movements |
IOL | Intraocular lens |
IOP | Intraocular pressure |
NRC | Normal retinal correspondence |
NV | Near vision |
sc | Without correction |
VA | Visual acuity |
VF | Visual field |
XT | Exotropia |