Med Term Ch 17

accommodation

adjustment of lens by ciliary body, normal adjustment of eye to focus on objects from far to near

anterior chamber

area behind cornea and in front of lens and iris

aqueous humor

fluid produced by ciliary body and found in anterior chamber of eye

biconvex

having two sides that are rounded, elevated, curved evenly, characteristic of lens of eye

choroid

vascular layer of eyeball that is continuous with iris, middle vascular layer of eye, between retina and sclera

ciliary body

containing muscles that control shape of lens and secrete aqueous humor, structure on either side of lens that connects choroid and iris, alters shape of lens

cone

photosensitive receptor cells of retina, make perception of color possible, contains sensitive cells (rods and cones) that transmit light energy to nerve impulses

conjunctiva

delicate membrane lining eyelids and covering anterior eyeball

cornea

fibrous layer of clear tissue that extends over anterior portion of eye and is continuous with white of eye

fovea centralis

tiny pit or depression in retina that is region of clearest vision

fundus of the eye

posterior, inner part of eye

iris

colored portion of eye, surround pupil

lens

transparent body behind iris and in front of vitreous humor, refracts light rays to bring them into focus on retina

macula

yellowish region on retina that contains fovea centralis

optic chiasm

place where optic nerve fibers cross brain

optic disc

region at back of eye where optic nerve meets retina

optic nerve

cranial nerve carrying impulses from retina to brain

pupil

dark center of eye through which light rays enter, dark opening of eye

refraction

bending of light rays by cornea, lens, fluids of eye to bring light rays into focus on retina

retina

light sensitive nerve cell layer containing photoreceptor cells (rods and cones)

rod

photoreceptor cell essential for vision in dim light and for peripheral vision

sclera

white potion of eye; tough, white outer coat of eyeball

thalamus

relay center of brain, optic nerve fibers pass through on their way to cerebral cortex

vitreous humor

jelly like material behind lens in posterior cavity of eye, helps to maintain shape of eyeball

aque/o

water

blephar/o

eyelid

conjunctiv/o

conjunctiva

cor/o

pupil

corne/o

cornea

cycl/o

ciliary body

dacry/o

tears, tear duct

ir/o

iris

irid/o

iris

kerat/o

cornea

lacrim/o

tears

ocul/o

eye

ophthalm/o

eye

opt/o

eye, vision

optic/o

eye, vision

palpebr/o

eyelid

papill/o

optic disc

phac/o

lens of eye

phak/o

lens of eye

pupill/o

pupil

retin/o

retina

scler/o

sclera, white of eye

uve/o

uvea, vascular layer

vitre/o

glassy

ambly/o

dull, dim

dipl/o

double

glauc/o

gray

mi/o

smaller, less

mydr/o

widen, enlarge

nyct/o

night

phot/o

light

presby/o

old age

scot/o

darkness

xer/o

dry

-opia

vision

-opsia

vision

-tropia

to turn

hyperopia

farsightedness, light rays are focused beyond instead of directly on retina

myopia

nearsightedness

presbyopia

condition of defective vision with advancing age, loss of accommodation, impairment of vision due to old age

cataract

clouding of lens, causing decreased vision

chalazion

small hard mass on eyelid formed from sebaceous gland enlargement

diabetic retinopathy

disease of retina due to long term effects of diabetes

glaucoma

disease of eye marked by fluid accumulation in anterior and posterior chambers of eye causing increased intraocular pressure and damage to retina

hordeolum (stye)

localized purulent infection of sebaceous gland in eyelid, retinal microaneurysms, hemorrhages occur secondary to endocrine condition

macular degeneration

loss of central vision, progressive damage to yellowish region on retina, deterioration of macula lutea of retina

nystagmus

repetitive, rhythmic movements of one or both eyes

strabismus

abnormal deviation of eye (esotropia and exotropia) caused by muscle weakness

retinal detachment

separation of two layers of retina from each other

scleral buckle

procedure to suture band of silicone on sclera directly over detached portion of retina

fluorescein angiography

process of recording blood vessels in back of eye after intravenous injection of dye

slit lamp microscopy

examination of ocular structures using slip lamp and microscope

visual acuity test

measurement of clearness of vision, assessed by reading letters of decreasing size on eye chart

visual field (VF) test

snellen chart that patient reads from to test clarity of vision

enucleation

removal of eyeball from orbit of eye

laser photocoagulation

use of laser to seal retinal tears and leaky retinal blood vessels

laser in situ keratomileusis (LASIK)

laser to correct errors of refraction by sculpting cornea

phacoemulsification

technique of cataract extraction using high frequency ultrasonic vibrations to remove clouded lens

auditory canal

channel that leads from auricle to eardrum

auditory meatus

channel leading from outer ear flap to eardrum

auditory nerve fiber

carrying impulses from inner ear to brain

auditory tube

eustachian tube

auricle

flap of ear

cerumen

waxy substance secreted by external ear

cochlea

snail shaped, spirally wound tube in inner ear, contains hearing sensitive cells

endolymph, perilymph

fluid within labyrinth of ear

eustachian tube

channel between middle ear and nasopharynx, tube connecting middle ear to throat

incus

second little bone of middle ear, shaped like anvil

labyrinth

maze like series of canals in inner ear

malleus

first little bone of middle ear, shaped like hammer

organ of corti

sensitive auditory receptive area in cochlea of inner ear

ossicle

small bone

oval window

membrane between middle and inner ear

perilymph

fluid contains in inner part of ear

pinna

auricle, flap of ear

semicircular canals

passages in inner ear associated with maintaining equilibrium