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the structures outside the eyeball: includes the orbit, eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus
adnexa of the eyes
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the bony cavity of the skull that contains and protects the eyeball and its associated muscles, blood vessels, and nerves.
aka eye socket
orbit
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the angle where the upper and lower eyelids meet
canthus
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where the eyelids meet nearest the nose
inner canthus
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a vertical fold of skin on either side of the nose
epicanthus
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where the eyelids meet farthest from the nose
outer canthus
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the framework within the upper and lower eyelids that provides the necessary stiffness and shape
tarsus
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the transparent mucous membrane that lines the underside of each eyelid and continues to form a protective covering over the exposed surface of the eyeball
conjunctiva
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consists of the structures that produce, store and remove tears
lacrimal apparatus
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secrete lacrimal fluid
lacrimal glands
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consists of a duct at the inner corner of each eye. Collect tears and empty them into the lacrimal sacs
lacrimal canal
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an enlargement of the upper portion of the lacrimal duct
lacrimal sac
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the passageway that drains excess tears into the nose
lacrimal duct
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aka the white of the eye
maintains the shape of the eye and protects the delicate inner layers of tissue. Forms the outer layer of the eye
sclera
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the opaque middle layer of the eyeball that contains many blood vessels and provides the blood supply for the entire eye.
choroid
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the sensitive innermost layer that lines the posterior segment of the eye
retina
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makes up the front one third of the eyeball
anterior segment
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located behind the cornea and in front of the iris
anterior chamber
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located behind the iris and in front of the ligaments holding the lens in place
posterior chamber
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the liquid that fills the chambers of the eye
aqueous fluid
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drains and filters the aqueous fluid
trabecular meshwork
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where the aqueous fluid drains through after passing through the trabecular meshwork
canal of Schlemm
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a measurement of the fluid pressure inside the eye
intraocular pressure
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makes up the remaining two thirds of the eyeball, lined with the retina and filled with the vitreous gel
posterior segment
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a soft, clear jelly like mass that contains millions of fine fibers
vitreous gel
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receptors that receive white and black
rods
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receptors that receive color
cones
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a clearly defined yellow area in the center of the retina. Area of sharpest central vision
macula
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the pit in the middle of the macula. Color area is best in this area because it contains a high concentration of cones and no rods
fovea centralis
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a small region in the eye where the nerve endings of the retina enter the optic nerve
aka blind spot
optic disk
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transmits nerve impulses from the retina to the brain
optic nerve
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the pigmented layer of the eye; has a rich blood supply and consists of the choroid, ciliary body and iris
uveal tract
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located within the choroid, it is a set of muscles and suspensory ligaments that adjust the thickness of the lens to refine the focus of light rays on the retina
ciliary body
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the process whereby the eyes make adjustments for seeing objects at various distances
accommodation
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the simultaneous inward movement of the eyes toward each other
convergence
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the normal relationship between the refractive power of the eye and the shape of the eye that enables light rays to focus correctly on the retina
emmetropia
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the ability of the lens to bend light rays so they focus on the retina
refraction
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the ability to distinguish object details and shape at a distance
visual acuity
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drooping of the upper eyelid that is usually due to paralysis
blepharoptosis
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a localized swelling inside the eyelid resulting from obstruction of a sebaceous gland
chalazion
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the eversion of the edge of an eyelid
ectropion
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the inversion of the edge of an eyelid
entropion
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a pus-filled lesion on the eyelid resulting from an infection in a sebaceous gland
aka a stye
hordeolum
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bleeding between the conjunctiva and the sclera
subconjunctival hemorrhage
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inflammation of the uveal tract affecting primarily structures in front of the eye
iritis
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pitting of the cornea caused by an infection or injury
corneal ulcer
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a benign growth on the cornea that can become large enough to distort vision
pterygium
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an adhesion that binds the iris to an adjacent structure such as the lens or cornea
synechia
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a condition in which the pupils are unequal in size. Can be congenital or caused by a head injury, aneurysm, or pathology of the central nervous system
anisocoria
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PERRLA (abbreviation that stand for..)
Pupils are equal, round, responsive to light and accommodation
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an involuntary, constant, rhythmic movement of the eyeball that can be congenital or caused by a neurological injury or drug use.
Nystagmus
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aka choked disc
swelling and inflammation of the optic nerve at the point of entrance into the eye through the optic disk
papilledema
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a progressive degeneration of the retina that affects night and peripheral vision. Can be detected by the presence of dark spots in the retina
Retinitis pigmentosa
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occurs as aging causes the vitreous gel to slowly shrink. The fine fibers within the gel pull on the retinal surface. Most cases it isnt sight threatening, but can cause a retinal tear.
Vitreous detachment
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a group of diseases characterized by increased intraocular pressure that cause damage to the retinal nerve fibers and the optic nerve
glaucoma
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most common form of this condition. The trabecular meshwork gradually becomes blocked, and this causes a build up of pressure. Symptoms aren't noticed until optic nerve has been damaged.
Open-angle glaucoma
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the opening between the cornea and iris narrows so that fluid cannot reach the trabecular meshwork. Produces severe pain, nausea and redness of the ey, and blurred vision. Can cause blindness in as little as two days.
Closed-angle glaucoma
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perception of two images of a single object
diplopia
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blindness in one half of the visual field
hemianopia
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color blindness
monochromatism
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night blindness
nyctalopia
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the condition of common changes in the eyes that occur with aging
presbyopia
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a disorder in which the eyes point in different directions or are not aligned correctly because the eye muscles are unable to focus together
strabismus
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walleye, or outward deviation of one eye relative to the other
exotropia
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a focusing problem that occurs when the lens and cornea do not bend light so that is focuses properly on the retina
refractive disorder
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any error of refraction in which images do not focus properly on the retina.
Astigmatism, hyperopia, and myopia are all forms
Ametropia
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a condition in which the eye does not focus properly because of uneven curvatures of the cornea
astigmatism
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farsightedness; light rays focus beyond the retina
hyperopia
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nearsightedness; light rays focus in front of the retina
myopia
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a dimness of vision or the partial loss of sight, esp in one eye, without detectable disease of the eye
amblyopia
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blind spot; an abnormal area of absent or depressed vision surrounded by an area of normal vision
scotoma
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used to measure visual acuity
Snellen chart
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an examination procedure to determine an eye's refractive error so that the best corrective lenses can be prescribed
refraction
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the unit of measurement of a lens' refractive power
diopter
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a diagnostic procedure in which a narrow beam of light is focused onto parts of the eye to permit the ophthalmologist to examine the structures at the front of the eye
slit-lamp ophthalmoscopy
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the measurement of intraocular pressure
tonometry
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the application of fluorescent dye to the surface of the eye. Causes a corneal abrasion to appear bright green
fluorescein staining
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a radiographic study of the blood vessels in the retina of the eye following the intravenous injection of a fluorescein dye as a contrast medium
fluorescein angiography
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performed to determine losses in peripheral vision
visual field testing
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surgical procedure to treat myopia, where incisions are made in the cornea to cause it to flatten.
radial keratotomy
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the use of ultrasonic vibration to shatter and remove the lens clouded by a cataract.
phacoemulsification
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an eye in which the natural lens has been replaced with an intraocular lens
pseudophakia
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uses a focused beam of light to create a hole in the iris of they
laser iridotomy
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used to treat open-angle glaucoma by creating openings in the trabecular meshwork to allow fluid to drain properly
laser trabeculoplasty
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the use of lasers to treat some forms of wet macular degeneration by sealing leaking or damaged blood vessels
photocoagulation
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aka the auricle; the external portion of the ear
pinna
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transmits sound waves from the pinna to the tympanic membrane of the middle ear
external auditory canal
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eardrum
tympanic membrane
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hollow air spaces located in the mastoid process of the temporal bone
mastoid bone cells
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three small bones found in the middle ear; ransmit the sound waves from the eardrum to the inner ear by vibration
auditory ossicles
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narrow tubes that lead from the middle ear to the nasal cavity and the throat
eustachian tubes
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labyrinth; contains the sensory receptors for hearing and balance
inner ear
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located under the base of the stapes; the membrane that separates the middle and inner ears.
oval window
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snail shaped fluid filled structure that forms the inner ear
cochlea
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fluid filled cavity within the cochlea that vibrates when sound waves strike it
cochlear duct
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receives the vibrations from the cochlear duct and relays them to the auditory nerve fibers
organ of Corti
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these contain the liquid endolymph and sensitive hair-like cells. Help maintain equilibrium.
Semicircular canals
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transmit information to the brain from the semicircular canals, to ensure that equilibrium is maintained
acoustic nerves
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the process by which sound waves enter the ear through the pinna
air conduction
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occurs as the eardrum vibrates and moves the auditory ossicles
bone conduction
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occurs when sound vibrations reach the inner ear. The structures of the inner ear receive the sound waves and relay them to the auditory nerve to go to the brain
sensorineural conduction
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swimmer's ear; a fungal infection of the external auditory canal
otomycosis
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distention of the eustachian tube
patulous eustachian tube
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associated with an upper respiratory infection and is most commonly seen in young children. Can lead to a ruptured eardrum
Acute otitis media
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fluid build up in the middle ear that can follow acute otitis media or can be caused by obstruction of the eustachian tube
serous otitis media
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a buildup of pus within the middle ear due to infection
acute purulent otitis media
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a rare chronic disease in which the amount of fluid in the inner ear increases intermittently, producing attacks of vertigo, a fluctuating hearing loss and tinnitus
Meniere's syndrome
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a ringing, buzzing or roaring sound in one or both ears
tinnitus
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a gradual loss of sensorineural hearing that occurs as the body ages
presbycusis
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occurs when sound waves are prevented from passing from the air to the fluid filled inner ear.
conductive hearing loss
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nerve deafness; develops when the auditory nerve or hair cells in the inner ear are damaged
sensorineural hearing loss
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the measurement of the ability to hear and understand speech sounds based on their pitch and loudness
audiological evaluation
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use of an audiometer to measure hearing acuity
audiometry
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measure of sound frequency that determines how high or low a pitch is
hertz
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commonly used as the measurement of the loudness of a sound
decibel
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use of air pressure in the ear canal to test for disorders of the middle ear
tympanometry
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surgical procedure in which a new opening is created in the labyrinth to restore hearing
fenestration
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