CH. 16 Special Senses

accomodation

Adjustment of the eye for various distances so that images focus on the retina of the eye

acuity

clearness or sharpness of a sensory function

adnexa

Tissues or structures in the body adjacent to or near a related structure

humor

any fluid or semifluid of the body

labyrinth

Series of intricate communicating passages

opaque

Substance or surface that neither transmits nor allows the passage of light

perilymph

Fluid that very closely resembles spinal fluid but is found in the cochlea

photopigment

Light-sensitive pigment in the retinal cones and rods that absorbs light and initiates the visual process; also called *visual pigment*

refractive

Ability to bend light rays as they pass from one medium to another

stereopsis

Depth perception provided by visual information derived from two eyes located in slightly different positions so that each produces its own unique view of an object

ambly/o

dull, dim

\-opia

vision

amblyopia

dull vision

aque/o

water

\-ous

pertaining to

blephar/o

eyelid

\-ptosis

prolapse

choroid/o

choroid

conjunctiv/o

conjunctiva

core/o

pupill/o

pupil

corne/o

cornea

cycl/o

ciliary body of the eye; circular cycle

dacry/o

lacrim/o

tear; lacrimal apparatus (duct, sac, or gland)

dacryocyst/o

lacrimal sac

glauc/o

gray

goni/o

angle

irid/o

iris

kerat/o

horny tissue; hard; cornea

ocul/o

opthalam/o

eye

opt/o

optic/o

eye, vision

phac/o

lens

phot/o

light

presby/o

old age

retin/o

retina

scler/o

hardening; sclera (white of eye)

scot/o

darkness

vitr/o

vitreous body (of the eye)

audi/o

hearing

labyrinth/o

labyrinth (inner ear)

mastoid/o

mastoid process

ot/o

ear

salping/o

tubes (usually fallopian or eustachian)

staped/o

stapes

typman/o

myring/o

tympanic membrane (eardrum)

\-acusia

\-cusis

hearing

\-opia

\-opsia

vision

\-tropia

turning

eso-

inward

exo-

outside, outward

hyper-

excessive, above normal

achromatopsia

Severe congenital deficiency in color perception; also called *complete color blindness*

ametropia

Failure of light rays to focus sharply on the retina as a result of a defect in the lens, cornea, or shape of the eyeball; also called *error of refraction* 

astigmatism

Distorted vision resulting from a defective curvature of the cornea or lens causing light rays to diffuse over a large area of the retina rather than being sharply focused

hyperopia

Visual defect in which the eyeball is too short, and the image falls behind the retina; also called *farsightedness*

myopia

Visual defect in which the eyeball is too long, and the image falls in front of the retina; also called *nearsightedness*

cataract

Opacity that forms on the lens and impairs vision, caused by proteins that slowly build up over time

chalazion

Small, hard tumor developing on the eyelid, somewhat similar to a sebaceous cyst; also called *meibomian cyst*

conjunctivitis

inflammation of the conjunctiva and inner eyelids with vascular congestion; also called *pinkeye*

drusen

Small yellowish deposits composed of retinal pigment cells that develop under the retina and are associated with an increased risk of developing age-related macular degeneration

ectropion

Eversion, or outward turning, of the edge of the lower eyelid, causing it to pull away from the eye, generally associated with aging and weakness of the small muscles around the eyelid

entropion

Inversion, or inward turning, of the edge of the lower eyelid, commonly causing friction as the eyelashes and outer eyelid rub against the surface of the eye

epiphora

abnormal overflow of tears

hordeolum

Localized, circumscribed, inflammatory swelling of one of the several sebaceous glands of the eyelid; also called *stye*

metamorphopsia

visual distortion of objects

nyctalopia

Impaired vision in dim light; also called *night blindness*

nystagmus

Type of involuntary eye movements that appear jerky and may reduce vision or be associated with other, more serious conditions that limit vision

papilledema

Swelling and hyperemia of the optic disc, usually associated with increased intracranial pressure; also called *choked disc*

photophobia

Unusual intolerance of and sensitivity to light

retinopathy

any disorder of retinal blood vessels

strabismus

Misalignment of the eyes so that they do not focus on the same object at the same time, sending two different images to the brain; also called *heterotropia* or *tropia*

trachoma

Chronic, contagious form of conjunctivitis that typically leads to blindness

anacusis

complete deafness; also called anacusia

conduction impairment

Blocking of sound waves as they pass through the external and middle ear (conduction pathway)

labyrinthitis

Inflammation of the inner ear that usually results from an acute viral disease, such as mumps, measles, or influenza

Ménière disease

Increased fluid pressure of the endolymphatic system that leads to progressive loss of hearing; also called *endolymphatic/labyrinthine hydrops*

noise-induced hearing loss (NIHL)

Condition caused by the destruction of hair cells, the organs responsible for hearing, as a result of sounds that are “too long, too loud, or too close”

otitis externa

Infection of the external auditory canal

presbycusis

Impairment of hearing resulting from old age; also called *presbyacusia*

tinnitus

Perception of ringing, hissing, or other sounds in the ears or head when no external sound is present

vertigo

Sensation of a spinning motion of oneself or of the surroundings

audiometry

Measurement of hearing acuity at differing sound-wave frequencies and volumes to detect the various types of hearing impairment

caloric stimulation test

Test that uses different water temperatures to assess the vestibular portion of the nerve of the inner ear (acoustic nerve) to determine whether nerve damage is the cause of vertigo

electronystagmography

Method of assessing and recording eye movements by measuring the electrical activity of the extraocular muscles

gonioscopy

Examination of the angle of the anterior chamber of the eye to determine ocular motility and rotation and diagnose and manage glaucoma

ophthalmodynamometry

Measurement of the blood pressure of the retinal vessels

ophthalmoscopy

Visual examination of the interior of the eye using a handheld instrument called an *ophthalmoscope,* which has various adjustable lenses for magnification and a light source to illuminate the interior of the eye

otoscopy

Visual examination of the external auditory canal and the tympanic membrane using an otoscope

pneumatic

Otoscopic procedure that assesses the ability of the tympanic membrane to move in response to a change in air pressure

retinoscopy

Evaluation of refractive errors of the eye by projecting a light into the eyes and determining the movement of reflected light rays

slit-lamp examination

Stereoscopic magnified view of the anterior eye structures in detail, which includes the cornea, lens, iris, sclera, and vitreous humor

tonometry

Evaluation of intraocular pressure by measuring the resistance of the eyeball to indentation by an applied force

tuning fork tests

Hearing tests using a vibrating tuning fork to determine type of hearing loss

Rinne

Tuning fork test that evaluates unilateral hearing loss by comparing sound through bone conduction (BC) versus air conduction (AC); also called *air and bone conduction hearing test*

Weber

Tuning fork test that determines whether hearing loss occurs in the middle ear (conductive hearing loss) or in the auditory nerves or hair cells of the inner ear (sensorineural); also called *conductive and sensorineural hearing loss test*

visual acuity (VA) test

Part of an eye examination that determines the smallest letters that can be read on a standardized chart at a distance of 20 feet and commonly expressed as a fraction

dacryocystography

Radiographic imaging procedure of the nasolacrimal (tear) glands and ducts

fluorescein angiography

Evaluation of blood vessels and their leakage in and beneath the retina after injection of fluorescein dye, which circulates while photographs of the vessels within the eye are obtained

blepharoplasty

Cosmetic surgery that removes fatty tissue above and below the eyes that commonly forms as a result of the aging process or excessive exposure to the sun

cochlear implant insertion

Placement of an artificial hearing device that produces hearing sensations by electrically stimulating nerves inside the inner ear; also called *bionic ear*

cyclodialysis

Formation of an opening between the anterior chamber and the suprachoroidal space for the draining of aqueous humor in glaucoma