Med Term Chapter 16

eyeball

special sense, responsible for vision

light rays travel through

cornea, pupil, iris, lens

light rays land on retina

produces image, message carried to brain via optic nerve

accessory organs

conjunctiva, eyelids, lacrimal glands

ophthalmologists

perform vision exams, prescribe corrective lenses, diagnose and treat eye conditions, perform eye surgery

doctor of optometry specializes in

assessing vision, prescribing corrective lenses, treating glaucoma, corneal damage, visual skill problems, screening for other eye diseases

aque/o

water

blephar/o

eyelid

choroid/o

choroid layer

conjunctiv/o

conjunctiva

core/o

pupil

corne/o

cornea

cycl/o

ciliary body

dacry/o

tears

ir/o

iris

irid/o

iris

kerat/o

cornea

lacrim/o

tears

ocul/o

eye

ophthalm/o

eye

opt/o

eye

phac/o

lens

pupill/o

pupil

retin/o

retina

scler/o

sclera

ton/o

tension, pressure

vitre/o

glassy

aden/o

gland

ambly/o

dull or dim

angi/o

vessel

chrom/o

color

cry/o

cold

cyst/o

sac

dipl/o

double

myc/o

fungus

nas/o

nose

phot/o

light

xer/o

dry

-opia

vision

aqueous humor

watery fluid in open areas of eye

cilia

eyelashes

choroid layed

middle layer of wall of eyeball, has many blood vessels

conjunctiva

mucous membrane, protects anterior surface of eyeball, turns underneath to line eyelids

cornea

• anterior portion of sclera

• transparent to allow light through

• curved to bend light rays so focus on retina

ciliary body

ring of muscle around outer edge of lens

• attached to lens by suspensory ligaments

• pulls on edges of lens to change shape in order to focus image onto retina

tear (secreted by what, flows through what to what?)

watery fluid secreted by lacrimal glands, moistens and cleanses

• collect in corner of eye and flow through lacrimal canals to lacrimal sac

lacrimal glands located

superior and lateral to eyeball and under orbital gone

iris

colored portion of eye, made of muscle and contracts or relaxes to change pupil size

the eye is

hollow, not empty

wall of eye has three layers

• sclera

• choroid

• retina

lens

transparent structure behind iris and pupil, bends light rays passing through so focused on retina

retina

inner layer of eyeball, contains light receptors called rods and cones

rods

function in dim light and see in gray tones

cones

see color in bright light

macula lutea

Area on posterior wall of eyeball, directly opposite lens

fovea centralis

small pit in center of macula, contains only rods and point of clearest vision

sclera

outermost layer of eye, commonly called white of eye, very fibrous and tough

vitreous humor

gel-like, shiny substance that fills large open cavity between lens and retina

accommodation (Acc)

ability of eye to adjust to variations in distance

achromatopsia

profound inability to see in color from birth (aka color blindness)

amblyopia

loss of vision not due to disease, not correctable w/glasses, (aka lazy eye)

• ppl wear patch over one eye to focus affected eye to work

astigmatism (Astigm)

uneven bending of light rays caused by irregular curvature of cornea, image is fuzzy, corrected w/cylindrical lenses

cataract

lens becomes cloudy or opaque, results in whole vision field becoming blurry, treatment usually surgical removal and replacement w/artificial lens

color vision tests

use of multi-colored charts to determine ability of patient to recognize color

corneal abrasion

scraping away of outer layer of cornea

cryoextraction

procedure to remove lens w/cataract using extremely cold probe

diabetic retinopathy

development of small hemorrhages and edema in retina as result of diabetes mellitus, dark spots appear in visual field, laser surgery may be necessary

fluorescein

bright green fluorescent dye dropped onto surface of eyeball to highlight corneal abrasions

fluorescein angiography

procedure using intravenous bright green fluorescent dye, fluorescein, to examine movement of blood through blood vessels of eye

glaucoma

condition resulting from increase in intraocular pressure, if untreated may result in atrophy of optic nerve and blindness, patient notices vision becomes blurry around edges, treated w/meds and surgery

hyperopia

visual condition where person can see things in distance but not close, corrected by convex lens (aka farsighted)

intraocular lens (IOL) implant

replacing defective natural lens w/artificial lens following cataract extraction

laser-assisted in-situkeratomileusis (LASIK)

correction of myopia using laser surgey to remove minute slices of corneal tissue

laser retinal photocoagulation

using laser to make pinpoint scars to stabilize detached or torn retina

macular degeneration

deterioration of macula lutea of retina, patient notices loss of vision in center of visual field

myopia (MY)

person can see close, not far, corrected by concave lens (aka nearsighted)

nyctalopia

poor night vision or dim light (aka night blindness)

nystagmus

jerky-appearing involuntary eye movement

optician

healthcare professional trained to make corrective lenses and fit eyeglasses and contact lenses

phacoemulsification

use of high-frequency sound waves to break a cataract, which is removed by suction with needle

photophobia

excessive sensitivity to light leading to avoidance, not fear of light

photo-refractive keratectomy (PRK)

use of laser to reshape cornea to improve visual activity

radial keratotomy (RK)

surgery w/spoke-like incisions in cornea to flatten it, done to correct nearsightedness

refractive error

defect in ability of eye to bend light rays to focus image properly on fovea centralis (refraction)

retinal detachment

retina becomes separated from choroid layer, separation seriously damages blood vessels and nerves, resulting in blindness

sit lamp microscope

instrument used in ophthalmology for examining posterior surface of cornea

Snellen chart

chart used for testing visual acuity, contains letters of varying size and given from distance of 20 feet, person who can read what average person can has 20/20 vision

• can see at 20 feet what normal person can

  • 20/200 = myopia - must be 20 feet away to see object that person can normally see at 200

strabismus

weakness of external eye muscle, results in eyes looking in different directions at same time, may be corrected w/glasses, eye exercises, and/or surgery (aka cross eyed if eye is towards nose)

strabotomy

incision in eye muscles to correct strabismus

stye

small purulent infection of sebaceous gland of eye, treated w/hot compresses and surgical incision (aka hordeolum)

visual acuity test (VA)

measurement of sharpness of vision, usually use snellen chart

Acc

accommodation

As; Ast

astigmatism

c. gl

correction w/glasses

cyl

cylindrical lens

D

diopter (lens strength)

ECCE

extracapsular cataract extraction

ICCE

intracapsular cataract cryoextraction

IOL

intraocular lens

IOP

intraocular pressure