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Med Term Mod17 *Eye*

Abn. Cond., Clinical Proc., Treatm. & Err. of Refraction

astigmatism defective curvature of cornea/lens of eye
abnormal condition in which light rays cannot come to a single point of focus on the retina; image is distorted astigmatism
the correct astigmatism cylindrical lens placed in proper position in front of eye to correct refractive error
hyperopia farsightedness
astigmatism is a problem resulting from one or more abnormal curvatures of cornea or lens
hyperopia is also known as hypermetropia
hyperopia is when eyeball is too short or lens lacks adequate focusing power
when parallel rays of light are focus behind retina a patient may suffer from hypermetropia
myopia nearsightedness
when a patient suffers from myopia there is elongation of the eyeball, or the refraction power of lens is too strong light rays do not properly focus on retina
image perceived is blurred because light rays focused on front of retina myopia
to correct myopia a doctor may prescribe concave glasses
the leses of concave glasses spread light rays out before reaching cornea allowing the light to properly focus directly on the retina
presbyopia impairment of vision as result of old age
ciliary body looses elasticity impairing ability to adjust lens to accomodate near vision in presbyopia
in presbyopia the lens cannot become fat to bend rays of light coming from objects less than 20ft
the light rays are focused behind the retina, making presbyopia similar to hyperopia
to correct presbyoia, a doctor would need to prescribe a convex lens, in order to refract light rays from objects closer than 20ft
cataract protein in lens aggregates & clouds vision
progressive, abnormal condition of lens characterized by a loss of transparency a cataract
most cataracts are produced by degenerative changes that accompany the aging process
some cataracts may be congenital
cataracts lead to gradual blurring of vision, as the lens becomes opaque, resulting in eventual loss of sight
the cloudiness of a lens can be seen with the naked eye, or by use of an ophthalmoscope
the surgical method to treat cataracts includes removal of lens & implant artifical lens behind iris
preferred position of artifical lens placement, to surgically treat cataracts, is behind the iris
patients may also wear eyeglasses/contact lenses to help refraction, if an intraocular lens cannot be inserted, as treatment for cataracts
senile cataracts are linked to the process of aging
cataracts can also be caused by trauma, infection, or other diseases, such as diabetes mellitus
prolonged high-dose cortisteriod administration have been linked to the development of cataracts
chalazion small, hard, granuloma on eyelid
a granuloma is a cystic mass
formed as a result of chronic inflammation of meibomian gland along margin of eyelid cause of a chalazion
often requires incision & drainage as treatment chalazion
diabetic retinopathy edema occurs as fluid leaks from blood vessels into retina & vision is blurred
retinal effects of diabetes mellitus microaneurysms, hemorrhages, dilation of retinal veins, & neovascularization
neovascularization new blood vessels form in retina
exudates appear in retina as yellowish-white spots diabetic retinopathy
treatment for diabetic retinopathy, for patient with severe hemorrhaging includes laser photocoagulation & vitrectomy
laser photocoagulation intense precisely focused argon lasar beam creates inflammatory reaction sealing retinal tears & leaking retinal blood vessels
vitrectomy removal of vitreous humor & replaced with a clear solution
necessary when bllod & scar tissue accumulate in viterous humor, complaition of diabetic retinopathy a vitrectomy
glaucoma loss of vision due to increased intraocular pressure causing damage to retina & optic nerve
inability of aqueous humor to drain from eye & enter into bloodstream causes elevated intraocular pressure, as seen in glaucoma
when fluid builds up, in glaucoma, the pressure is elevated precisely in the anterior chamber of aqueous humor
tonometry is the method used to diagnose glaucoma
tonometry instrument applied externally to eye, after local anesthetic administered
marked by extreme ocular pain, blurred vision, redness of eye, & dilation of pupil glaucoma
a patient with chronic glaucoma may experience no symptoms initially
a patient with glaucoma may experience a gradual loss of peripheral vision, headaches, blurred vision, & halos around bright lights
is untreated glaucoma will results in blindness
drugs to lower intraocular pressire can control the condition of glaucoma
lasar therapy, iridotomy, can reduce intraocular pressure in patients with glaucoma
iridotomy lasar therapy creates hole in periphery of iris allowing aqueous humor to easily flow into anterior chamber, reducing intraocular pressure
in chronic glaucoma lasar therapy causes scarring in drainage angle, which improves aqueous humor outflow & reduces intraocular pressure
hordeolum is also known as a stye/sty
hodeolum localized, purulent, inflammatory staphylococcal infections of a sebaceous gland in eyelid
treatment for a stye/sty includes hot compresses to help localize infection & promote drainage; sometimes incision if necessary
Latin hordeolum means barley corn
macular degeneration progressive deterioration of macula of retina & choroid layer of eye
one of leading causes of elderly blindness is age-realted macular degeneration (AMD)
someone suffering from macular degeneration will retain peripheral vision, using part of retina outside macular region
dry form of macular degeneration, affecting 85% of patients, is marked by atrophy & degeneration of retinal cells & deposits clumps of drusen; no treatment
drusen extracellular debris
wet form of macular degeneration is characterized by formation of new and fragile vessels that leak blood
exudative leaky
neovascular new
treatment for the wet form of macular degeneration includes laser photocoagulation of leaking vessels, although patients have more severe vision loss so sucess of treatment is limited
nystagmus repetitive rhythmic movements of one/both eyes; normal in newborns
brain tumors or diseases of inner ear may cause nystagmus
retinal detachment two layers of retina separate from each other
trauma to eye, head injuries, bleeding, scarring from infection or shrinkage of vitreous humor can produce holes/tears in retina & result in retinal detachment
photopsia seeing bright flashes of light
patients suffering from retinal detachment often experience photopsia & then notice a shadow/curtain falling across field of vision
floaters black spots, usually composed of viterous clumps that detach from retina
floaters can be a sign of retinal hole, tear, or detachment
floaters can becaused by pigmented cells from damaged retina or bleeding as result of detachment of retina
smaller retinal tears, retinal detachment, can be treated using photocoagulation or cryotherapy
photocogulation to treat retinal tears making pinpoint burns to form scar tissue to seal holes
cryotherapy to treat retinal tears creating a "freezer burn" that forms a scar & knits a tear together
scleral buckle is a method used to treat larger retinal detachments
scleral buckle suture of a silicone band to sclera directly over detached portion of retina to push two retinal layers together
in selected retinal detachments a procedure that is performed is called pneumatic retinopexy
pneumatic retropexy a gas bubble is injected into vitreous cavity putting pressure on are of retinal tear until retina reattached
strabismus inability of the eyes to focus simultaneously on the same object
esotropia one eye turns inward; cross-eyed; form of strabismus
extropia one eye turns outward; wall-eyed; form of strabismus
hypertropia upward deviation of one eye; form of strabismus
hypotropia downward deviation of one eye; form of strabismus
eye drops, corrective lenses, eye excerises & patching of normal eye, or surgery to restore muscle balance are all forms of treatment for strabismus
strabismus in children can lead to amblyopia
amblyopia partial loss of vision, or lazy eye
amblyopia is reversible until retina fully developed, at about 7years old
diplopia double vision
when strabismus develops in an adult a common problem is diplopia
florescein angiography intravenous injection of florescein followed by serial photographs of retina through dilated pupils
test that provides diagnostic info about retinal blood flow, detects vascular changes in diabetic/hypertensive retinopathy, & identifies lesions in macular area of retina florescein angiography
ophthalmoscopy visual exam of interior of eye
pupil is dialated & physician uses instrument close to patient's eye, shining light into back of eye process of ophthalmoscopy
slit lamp microscopy instrument that combines a microscope and a light source, allowing magnified examination of the interior of the eye
procedure that provides magnified view of conjuctive, sclera, cornea, anterior chamber, iris, lens, & vitreous slit lamp microscopy
there are additional devices that can be attached to a slit lamp microscope to expand scope of examination
special magnifying lenses, added to slit lamp microscope, permit examination of fundus, as with a direct ophthalmoscope
visual acuity clarity of vision assessed; expressed as ratio, such as 20/20
patient reads from Snellen chart at 20 feet, during visual acuity testing
the first number from the visual acuity ratio is distance patient standing from chart
the second number from the visual acuity ratio is distance patient with normal vision could read same line of chart
if a patient's visual acuity ratio is 20/200 it means at 20ft patient can see what a "healthy eye" can see at 200ft
measurements can be taken at less than 20ft & still be equivalent to vision measured at 20ft when mirrors are used during visual acuity test
visual field test measures area within which objects are seen when eyes are fixed looking ahead without head movement
enucleation removal of entire eyeball
surgical treatment necessary to treat tumors or if an eye becomes blind & painful from trauma/disease enculeation
ocular melanoma malignant tumor of pigmented cells in choroid layer
keratoplasty surgical repair of cornea
penetrating keratoplasty is also known as corneal transplant
ophthalmic surgeon removes patient's scarred/opaque cornea & replaces with donor cornea, which is sutured into place process of keratoplasty
donor cornea is also called "button" or graft
procedure useful in treating retinal tears, diabetic retinopathy, & macular degeneration laser photocoagulation
in laser photocoagulation, laser is an acronym for light amplification by stimulated emission of radition
LASIK use of an excimer laser to reshape cornea, thus correctin refractive error
surgeon lifts top layer of cornea, by making a flap, & uses laser to scuplt cornea; cornea flap then repositioned LASIK
LASIK is an acronym for laser in situ keratomileusis
keratomileusis shaping of the cornea
phacoemulsification ultrasonic vibrations break up lens
typical surgery for cataract removal is phacoemulsification
ophthalmic surgeon uses small, scleral tunnel or self-sealing corneal incision & in most patients foldable IOL implanted process for phacoemulsification
photorefractive keratectomy laser beam flattens cornea to correct refractive error; LASIK
conjunctivitis inflammation of conjunctiva
corneal abrasion rubbing off of a part of outer layer of cornea
cycloplegia paralysis of muscles of ciliary body
dacryoadenitis inflammation of tear glands
iritis inflammation of the iris
keratitis inflammation of the cornea
miotic drug that causes pupil to contract
nyctalopia night blindness
difficult, or poor vision at night nyctalopia
ophthalmologist medical doctor specializing in diseases of eye
ophthaloplegia paralysis of muscles that move the eyeball
optician non-medical professional trained in grinding lenses & fitting eyeglasses
optometrist non-medical professional trained in grinding lenses & fitting eyeglasses
papilledema swelling of optic disc; associated with increased pressure within the eye
photophobia sensitivity to light
retinitis pigmentosa inflammation of retina with pigmentation & progressive scarring of tissue
scleritis inflammation of sclera
uveitis inflammation of uvea, which is vascular layer of the eye
xerophthalmia condition of excessive dryness of the eye
defects of the refractive media that interfere with visual acuity include irregularities in curvature of cornea, focusing power of lens, & length of eye
the most common visual problem is refractive error
the most common refractive error is myopia
Snellen chart contains letters of decreasing size, is often used to measure visual sharpness
may occur as esult of muscle weakness, genetic inheritance, or may accompany disease/injury to brain strabismus
visual conditions attributable to muscle weakness include diplopia & amblyopia
aspiration insertion os a hollow needle to withdraw lens tissue
aspiration is followed by irrigation of anterior chamber
intracapsular extraction entire lens excised after phacoemulsification
extracapsular extraction leaving the back part of the thin capsule that surrounds the lens in place after phacoemulsification
loss of vision associated with diabetic retinopathy may be caused by scarring following the development of hemorrhages, edema resulting from fluid leakage, or the rupture of the new blood vessels, which bleed into vitreous
diabetic retinopathy is idenitfied by careful ophthalmoscopic & slit lamp exams; florescein angiography is also used
Ophthalmoscopy and fluorescein angiography are the methods used to diagnose AMD
this procedure may be used in addition to ophthalmoscopy & slit-lamp microscopy to diagnose retinal detachment ultrasonography
ultrasonography may help to identify a separated retina if the structure itself cannot be visualized
primary open-angle glaucoma (POAG) glaucoma occurs as a primary disorder
glaucoma may also occur as secondary to systemic illness or trauma
Blockage of the outflow channels for aqueous humor may happen suddenly causing acute glaucoma
Blockage of the outflow channels for aqueous humor may progress at so slow a pace that the loss of vision is not recognized until it becomes extensive
acute glaucoma is a medical emergency
extreme ocular pain, blurred vision, a red discoloration of the eye, dilation of the pupil, and, possibly, nausea and vomiting symptoms of acute glaucoma
elevated intraocular pressure causes the optic disc to become wider, deeper, and paler
ophthalmoscopy allows visualization of changes to the optic disc
one of several procedures used to diagnose glaucoma ophthalmoscopy
gonioscope assesses the angle of the anterior chamber
tonometer instrument used to measure intraocular pressure
miotics can be used to treat glaucoma, by improving drainage of aqueous humor & decrease its production
trabeculectomy surgery to modify outflow channels or create new opening for escape of aqueous humor from anterior cavity
filtering procedure to treat glaucoma trabeculectomy
lasar therapy for the treatment of glaucoma causes scarring in drainage angle to improve aqueous humor outflow
congenital glaucoma can cause scarring and the formation of opacities on the cornea
patient's with congenital glaucoma may require replacement of cornea via keratoplasty
Neoplastic disease may affect any of the structures of the eye
many malignancies of structures of the eye can be managed with radiation and chemotherapy
following enucleation this can be inserted a permanent ocular prosthesis