Question | Answer |
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 |