Chapter 14 Flashcards
Orbit
hollow socket in the anterior skull
Iris
colored, circular structure in the eye
Pupil
a round opening that allows light rays to enter the eye
Mydriasis
muscles relax in dim light to dilate the pupil
Miosis
muscles contract in bright light to constrict the pupil
Lacrimal gland
located in the superior-lateral aspect of each eye
accommodation
change in the shape of the lens as the muscles of the ciliary body contract or relax to move the suspensory ligaments to the lens
Anterior cavity
area at the front of the eye that consists of the anterior chamber and the posterior chamber
Anterior chamber
very small space between the cornea and the iris
aqueous humor circulates through it
Aqueous humor
clear, watery fluid produced continuously by the ciliary body
Canal of schlemm
circular canal around the iris
aqueous humor from the trabecular meshwork flows through the canal of schlemm and is absorbed by a nearby vein
Choroid
spongy membrane of blood vessels that begins at the iris and continues around the posterior eye
Ciliary body
extension of the choroid
Conjunctiva
delicate, transparent mucous membrane that covers the inside of the eyelids and the anterior surface of the eye
Cornea
transparent layer over the anterior surface of the eye that allows light to enter the eye and bends the light rays
Cranial nerve II
carries sensory information of visual images from the retina to the optic chiasm in the brain for the sense of light
aka optic nerve
Cranial nerve III
carries motor commands to move four extraocular muscles, move the eyelids, and change the size of the pupil
aka oculomotor nerve
Cranial nerve IV
carries motor commands to move the superior oblique extraocular muscle
aka trochlear nerve
Cranial nerve V
carries sensory information from the eyelids and eyebrows to the brain
Cranial nerve VI
carries motor commands to move the lateral rectus extraocular muscle
Cranial nerve VII
carries motor commands to the lacrimal glands to produce tears
Extraocular muscles
six muscles that are attached to the sclera by tendons and move the eye in all directions
- superior rectus muscle
- inferior rectus muscle
- medial rectus muscle
- lateral rectus muscle
- superior oblique muscle
- inferior oblique muscle
Iris
colored circular structure around the pupil
Lacrimal gland
gland in the superior-lateral aspect of the eye
continuously produces and releases tears through the lacrimal duct
Lacrimal sac
structure that collects tears as they drain from the medial aspect of the eye
sac empties into the nasolacrimal duct
Lens
transparent, flexible disk posterior to the pupil
Lens capsule
clear membrane that surrounds the lens
Miosis
contraction of the muscles of the iris to constrict the pupil and limit the amount of bright light entering the eye
Mydriasis
relaxation of the muscles of the iris to dilate the pupil and increase the amount of bright light entering the eye
Nasolacrimal duct
structure that carries tears from the lacrimal sac to the inside of the nose
Orbit
hollow bony socket in the anterior skull where the eyeballs go
Posterior chamber
very narrow space posterior to the iris
Pupil
dark, round, central opening in the iris that allows light rays to enter the posterior cavity
Sclera
white, opaque, tough, fibrous, connective tissue that forms the outer layer around most of the eye, protects the internal structures, and maintains the shape of the eye
aka the white of the eye
Trabecular meshwork
interlacing fibers around the edge of the iris
Uvea
collective word for the iris, choroid, and ciliary body
aka uveal tract
Fovea
small depression in the center of the macula
area of sharpest vision and lies directly opposite the pupil
Fundus
general word for the retina because it is he area that is farthest from the opening (pupil)
Macula
dark, yellow-orange circular area with indistinct edges located on the retina
contains the fovea
Optic disk
bright, yellow-white circle in the retina where the optic nerve and retinal arteries enter, and the retinal veins leave, the posterior cavity
Posterior cavity
large space between the lens and the retina that is filled with vitreous humor
Retina
thin layer of tissue that lines the posterior cavity
aka fundus
Vitreous humor
clear, gel-like substance that fills the posterior cavity and helps maintain the shape of the eye
Cones
light-sensitive cells concentrated in the macula of the retina that detect color
three cones which respond to only red, green, or blue light
Optic chiasm
area of the brain where part of each optic nerve crosses over to join part of the optic nerve from the other side
Refraction
the bending and focusing of light rays as they pass through the cornea and then through the lens
Rods
light-sensitive cells in the retina that detect black and white but not color
in low light they produce a grainy, black and white image
Stereoscopic vision
three dimensional vision with depth and distance perception
Thalamus
area in the brain where sensory images can be quickly interpreted so there can be a quick motor reflex to blink or move away
Visual cortex
area in the right and left occipital lobes of the brain. it merges the images from both eyes to create a single image
Visual field
the field of vision, including all objects that can be seen, centrally and to the side
Blepharitis
infection of inflammation of the eyelids
Blepharoptosis
drooping of the upper eyelid from excessive fat or sagging of the tissues due to age
Ectropion
injury or a growth on the lower eyelid that causes it to turn outward
Entropion
the lower eyelid turns inward because of weakening of the muscles and tendons
Hordeolum
red, painful swelling or a pimple containing pus on the eyelid
Dacryocystitis
bacterial infection of the lacrimal sac
Xerophthalmia
insufficient production of tears resulting in eye irritation
occurs with aging, because of an ectropion, or as a side effect of certain drugs
aka dry eyes syndrome
Conjunctivitis
inflamed, reddened, and swollen conjunctiva with dilated blood vessels in the sclera
Corneal abrasion
damage to the cornea due to trauma or repetitive irritation, such as a foreign particle under a contact lens
Exophthalmos
pronounced outward bulging of the anterior surface of the eye with a startled, staring expression
Scleral icterus
yellow discoloration of the conjunctivae, which makes the sclerae also appear yellow
caused by jaundice
Nystagmus
involuntary rhythmic motions of the eye, particularly when looking to the side
Strabismus
deviation of the eye, either medially or laterally
aka cross eye
Anisocoria
unequal size of the pupils
caused by glaucoma, head trauma, stroke, or a tumor that damages the cranial nerve that controls the muscle of the iris
Glaucoma
increased intraocular (IOP) because aqueous humor cannot circulate freely
Open angle glaucoma
angle where the edges of the iris and cornea meet is normal and open, but the trabecular meshwork is blocked
painless but it destroys peripheral vision
Closed angle glaucoma
angle itself is too narrow and blocks the flow of aqueous humor
causes severe pain, blurred vision, and photophobia
Hyphema
blood in the anterior chamber
caused by trauma or increased intraocular pressure from glaucoma
Photophobia
abnormal sensitivity to bright light
can be associated with inflammation of the eye, or it can be due to increased intracranial pressure or meningitis in the brain
Uveitis
infection or inflammation of the uvea, which is a collective word for the iris, choroid, and ciliary body
Aphakia
condition in which the lens of the eye has been surgically removed because of a contract
Cataract
clouding of the lens
Presbyopia
loss of flexibility of the lens with blurry near vision and loos of accommodation
Color-deficient vision
genetic condition in which the cones are absent or do not contain enough visual pigment to respond to the light from colored objects
aka color blindness
Diabetic retinopathy
chronic, progressive condition of the retina in which a large number of new, fragile blood vessels form in patients with uncontrolled diabetes mellitus
Floaters and flashers
floaters are clumps, dots, or strings of collagen molecules that form in the vitreous humor because of aging and appear as spots in the visual field
flashers are brief bursts of bright light that occur in the visual field when the vitreous humor pulls on the retina
Macular degeneration
chronic, progressive loss of central vision as the macula degenerates
Night blindness
marked decrease in visual acuity at night or in dim light
Papilledema
inflammation and edema of the optic disk
Retinal detachment
separation of the retina from the choroid layer beneath it
Retinitis
infection or inflammation of the retina
Retinoblastoma
cancerous tumor of the retina in children, arising from abnormal embryonic retinal cells
Retinopathy of prematurity
retina in a premature baby develops abnormal blood vessels that can cause vision loss
Astigmatism
surface of the cornea is curved more steeply in one area, so there is no single point of focus on the retina
Hyperopia
light rays from a distant object focus correctly on the retina, and so the patient sees a distant object in sharp focus
Myopia
light rays from a near object focus correctly on the retina, and so the patient sees a near object in sharp focus
Amblyopia
condition in which the brain ignores the visual image coming from an eye with strabismus or coming from an eye in which the vision is unfocused or cloudy
Blindess
condition of complete or partial severe loss of vision
Diplopia
two visual fields are seen rather than one fused image
Scotoma
temporary or permanent visual field defect in one or both eyes
Fluorescein angiography
procedure in which fluorescein is injected intravenously to reveal retinal leaking and hemorrhages by using flash photography
Ultrasonography
radiologic procedure that uses ultra high frequency sound waves to create an image of the eye
image is a sonogram
Accommodation
procedure to test the ability of the muscles in the ciliary body to accommodate as demonstrated on near and distance visual acuity tests
Color deficient vision testing
procedure to determine if the patient has a defect in the red, green, or blue cones in the retina
Dilated funduscopy
procedure to examine the posterior cavity
Eye examination
during an eye examination, the ophthalmologist asks about the patients medical history and specifically any problems with vision
Eye patching
procedure in which the eye is covered with a soft bandage and a hard outer shield after eye trauma or eye surgery
Fluorescein staining
procedure in which a fluorescein (fluorescent dye) strip or drops are applied topically to the cornea to detect corneal abrasions and ulcers
Gaze testing
procedure to test the extraocular muscles
Conjugate gaze
when both eyes move together as a unit
Dysconjugate gaze
when the eyes do not move together
Convergence
tests the medical rectus muscles
Gonioscopy
procedure to look for blockage of the trabecular meshwork in open angle glaucoma
Peripheral vision
procedure to test visual acuity at the edges of the visual field
Phorometry
procedure to select from many different lenses to find the strength of lens that corrects the patients refractive error and produces 20/20 vision
Pupillary response
procedure to test that the pupils constrict briskly and equally in response to a bright light
PERRL
Pupils
Equal
Round and
Reactive to
Light
Slit-lamp examination
procedure to look for abnormalities of the cornea, anterior chamber, trabecular meshwork, iris, or lens
Tonometry
procedure to detect increased intraocular pressure and glaucoma