Chapter 17 Eye Flashcards
pupil
central dark opening of the eye
iris
colored portion of the eye
conjunctiva
membrane lining the inner surfaces of the eyelids
cornea
fibrous, transparent tissue that extends like a dome over pupil and iris
refraction
bending of light rays by the cornea
sclera
opaque white of the eye
choroid
dark brown membrane inside sclera
accomodation
normal adjustment of the eye to focus on objects from near to far
anterior chamber
area behind the cornea and in front of the lens and iris
aqueous humor
fluid produced by the ciliary body and found in the anterior chamber
biconvex
consisting of two surfaces that are rounded, elevated, and curved evenly like a sphere.
ciliary body
structure surrounding the lens that connects the iris to the choroid
cone
photoreceptor cell in the retina that transforms light energy into a nerve impulse
- responsible for color and central vision
fovea centralis
tiny pit or depression in the retina that the region clearest vision
fundus of the eye
posterior, inner portion of the eye
- visualized with a opthalmoscope
lens
small transparent, biconvex body behind the pupil of the eye
- it bends light rays to bring them into focus on the retina
macula
small oval region on the retina near the optic disc
- contains fovea centralis
optic chiasm
point at which optic nerves cross in the brain
optic disc
region at the back of the eye where the optic nerve meets the retina
- it is the blind spot in the eye due to lack of rods and cones (only nerve fibers)
optic nerve
cranial nerve carrying impulses from retina to the brain
rod
photoreceptor cell of the retina for vision in low light and for peripheral vision
thalamus
relay center of the brain
- optic nerve fibers pass through the thalamus on their way to the cerebral cortex
vitreous humor
soft, jelly-like material behind the lens in the vitreous chamber
- helps maintain the shape of the eye
astigmatism
defective curvature of the cornea or lens of the eye
hyperopia
hypermetropia
farsightedness
myopia
nearsightedness
presbyopia
impairment of vision as a result of old age
cataract
clouding of the lens, causing decreased vision
chalazion
small, hard cystic mass (granuloma) on the eyelid
diabetic retinopathy
disease of the retina caused by diabetes melitus
macular edema
fluid leaks from blood vessels into the retina and vision is blurred
exudates
fluid leaking from the blood
glaucoma
increased intraocular pressure results in damage to the retina and optic nerve with loss of vision
tonometry
diagnoses glaucoma
- instrument applied externally to eye + anesthetic
trabeculoplasty
laser therapy for chronic open angle glaucoma
blepharitis
inflammation of the eyelid causing redness, crusting, and swelling
chalazion
granuloma formed around an inflamed sebaceous gland
dacryocystits
blockage, inflammation, and infection of the nasolacrimal duct and lacrimal sac
- causes swelling and redness in the region between nose and lower lid
ectropion
outward sagging and eversion of the eyelid
- leads to improper lacrimation, corneal drying, and ulceration
entropion
inversion of the eyelid
- lashes rub against the eye and corneal abrasion may result
hordeolum (stye)
small, superficial white nodule along lid margin due to infection of sebaceous gland
ptosis
drooping of upper lid margin from neuromuscular margin
xanthelasma
raised yellowish plaque on eye lid
nystagmus
repetitive rhythmic movements of one or both eyes
retinal detachment
two layers of the retina separate from each other
photopsia
bright flashes of lightr
abismus
abnormal deviation of the eye
esotropia
one eye turns inward
- cross eyes
exotropia
one eye turns out
hypertropia
upward deviation of one eye
hypotropia
downward deviation of one eye
amblyopia
partial loss of vision
- aka lazy eye
diplopia
double vision
fluoreacein angiography
intravenous injection of fluorescein dye followed by serial photographs of the retina through dilated pupils
ophthalmoscopy
visual exam of the interior eye
optical coherence tomography (OCT)
non-invasive imaging technique using light waves to take cross-sectional pictures of the retina
slit lamp microscopy
exam of exterior ocular structures under microscopic magnification
visual acuity test
clarity of vision is assessed
visual field test
measurement of the entire scope of vision
enucleation
removal of the entire eyeball
keratoplasty
surgical repair of the cornea
laser photocoagulation
intense, precisely focused light beam (argon laser) creates an inflammatory reaction that seals retinal tears and leaky retinal blood vessels
lasik
use of an excimer laser to correct errors of refraction
- myopia, hyperopia, astigmatism
phacoemulsification
cataract removal surgery
- ultrasonic vibrations breakup the lens
scleral buckle
suture of a silicone band to the sclera over a detached portion of the retina
vitrectomy
removal of the vitreous humor