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108 Cards in this Set
- Front
- Back
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Primary function of the eye
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-encode light and carry information to brain, the brain interprets the information
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Extraocular Structures
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-protect from the foreign bodies
-regulate entry of light -distribute tears by blinking |
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Extraocular Structures-Conjuctiva
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-thin, transparent mucous membrane that lubricates the eye
-lines inner surfaces of eyelids and folds over anterior surface of eyeball -palpebral conjunctiva lines upper and lower eyelids -bulbar conjunctive-loosely covers anterior sclera |
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Extraocular structures-extrinsic eye muscles
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-control eye movement
-help maintain shape of eyeball -controlled by cranial nerves |
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Intraocular structures-sclera
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-protects and gives shape to eyeball
-gives way to cornea over iris and pupil |
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Intraocular structures-cornea
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-transparent, avascular, sensitive to touch
-allows light to enter eye and ispart of eye's light-bending apparatuus -corneal reflex-eyelids blink when cornea is touched, tears are also secreted |
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Intraocular structures-Iris
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-a disc of muscle surrounding pupil and lying between cornea and lens
-gives eye its color -regulates light entry by contracting pupil size |
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Intraocular Structures-Pupil
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-constricts when light enters and when used for near vision
-dilates in dim light and when used for far vision |
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Intraocular structures-anterior cavity
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-consists of anterior chamber, posterior chamber, and canal of schlemm
-anterior chamber-space between cornea and iris -posterior chamber -space bwtween iris and lens -a network of channels that circle the eye in the angle at the juction of the sclera and cornea -drainage system for fluid moving between anterior and posterior chambers |
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Intraocular structures-Aqueous Fluid/Humor
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-in anterior cavity of eye
-clear fluid -constantly formed and drained to maintain a relatively constant pressure of 15-20 mmHg in eye -provides nutrients and oxygen to cornea and lens |
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Intraocular structs-internal chamber
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-contains lens, posterior cavity, vitreous humor, ciliary body, uvea, and retina
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Intraocular structures-Lens
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-convex, avascular,transparent
-located directly behind pupil -can change shape to focus and refract light onto the retina |
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Intraocular structures-posterior cavity
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-lies behind lens
-filled with vitreous humor (clear, gelatinous) |
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Vitreous humor
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-lies behind the lens in the posterior cavity
-supports posterior surface of lens -maintains position of retina -transmits light |
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Intraocular structures-Uvea (Vascular tunic)
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-the middle layer of the eyeball
-three components-iris, ciliary body, choroid |
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Three components of uvea
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-iris
-ciliary body -choroid |
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Ciliary Body
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-encircles lens
-along w/ iris, regulates amount of light reaching retina by controlling shape of lens |
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Choroid
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-pigmented and vascular
-its blood vessels nourish layers of eyeball -its pigmented layers absorb light, preventing it from scattering within eyeball |
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Rods and cones
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Ishihar test-evaluates color vision
Rods-dim light and peripheral vision are more sensitive than cones, so we don't see colors as well in the dark cones-bright light and perception of color |
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Optic disc (blind spot)
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-cream-colored, round
-the point at which the optic nerve enters the eye -physiologic cup-a slight depression in the center of the optic disc -macula-lateral to optic dis-contains cones -fovea centralis-a slight depression in center of macula-contains cones-a main receptor of detailed color vision |
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Physiologic cup
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-part of optic disc
-a slight depression in the center of the optic disc |
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Macula
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-part of the optic disc
-lateral to optic dis-contains cones |
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Fovea Centralis
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-in optic disc
-slight depression in center of macula -contains cones -main receptor of detailed color vision |
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In your visual patway your optic nerves meet where? Where is the location of the tracts?
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-meet at the optic chiasma (in intersection of 2 tracts)
-just anterior to the pituitary gland -at the optic chiasma, axons from the medial half of each retina cross to opposite sides to form pairs with axans of the other -these pairs continue as the right and left optic tracts -these tracts carry information from both eyes -visual impulse travels in optic tracts to thalamus and synapse with neurons, forming pathways called optic radiations -optic radiations terminate in visual cortex of occipital lobe -visual cortex fuses information from each eye into one image |
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Refraction
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-bending of light rays as they pass from one medium to another medium of different optical density
-because the lens in convex, the image is projected onto the retina upside down and reversed from left to right -the brain decodes the image so it is perceived as it actually occurs |
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Accommodation
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-the eys are best adapted to see distant objects
-for persons w/ normal vision, the distance from the viewed object at which the eyes require no accommodation is 20 feet (perfect eyes) -accommodation is accomplished by contraction of ciliary muscles -near point of vision-closet point on which a person can focus, usually 8-10 " in young adults with normal vision -pupillary constriction also eliminated most divergent light rays and sharpens focus. |
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Convergence
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-refers to the medial rotation of the eyeballs so that each is directed toward the viewed object
-allow the focusing of the image on the retinal fovea of each eye |
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Diagnostic tests for the eye
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-retinoscopy and/or refractometry-test for refractive errors
-tonometry-tests for increased intraocular pressure -CT scan |
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Genetic eye disorders
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-Glaucoma- ~3% is genetic
-gyrate atropy of choroid and retina -best disease |
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amsler grid
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-physical assessment
-used to ID early changes in vision related to diabetes and mascular degeneration -hold grid 12-14", cover one eye, stare at the center dot -done when pupils are dilated and pt is wearing best visual corrections |
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Abnormal amsler grid findings
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-any of grid looks crooked or bent
-any of the boxes are different in size or shape -if any of the lines are wavy, missing, blurry or discolored |
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Age related changes
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-decreased elasticity of lens, decreaseing focus and accommodation for near vision (presbyopia)
-yellowing of lens, changes in retina affect color vision -pupil-decrease in size and responsiveness to loght -narrowing of visual fields -distorted depth perception -loss/decreased function of photoreceptors cells -adaptation to light and dark takes longer -decreased reabsorption of intraocular fluid -decreased tear production -vitreous body may pull away from retina |
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Myopia
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-nearsightedness-changes in distant vision
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hyperopia
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-farsightedness
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presbyopia
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-changes in near vision resulting in changes in lens elasticity due to aging (another name for farsightedness occurring in persons over age 45)
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Nystagmus
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-involuntary rhythmic movement of eyes, associated with neurologic disorders, somemeds, sometimes seen in persons wo were premies
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Foster safety and independence for a blind patient
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-orient to environment verbally and physically
-use verbal communication freely -provide other sensory stimuli per patient's preferences -orient to food trays (clock face) -when assisting w/ ambulation, ask pt to hold your arm while you walk slightly ahead -ask pt what assistance is disired -refer to community services if new loss of sight |
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Conjunctivitis
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-bacterial
-viral -fungal |
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Conjuctivitis-bacterial
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-staph, hemophilus
-pink eye-very contagious |
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adenovirus
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leading cause of conjunctivitis in adults
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Systemic/ other infections that may affect eye
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-herpes simplex, herpes zoster, gonococcus
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Conjuctivitis symptoms
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-pharyngitis
-fever -malaise -swollen preauricular lymph nodes |
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trachoma
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-bacterial
-chronic conjunctivitis caused by chlamydia trachomatis -preventable cause of blindness -common in Sahara, Africa, Middle east, and parts of asia |
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Conjuctivitis-Infection control
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-very contagious
-close personal contact transmission -also transmitted by fomites suchh as towels, handkerchiefs, flies |
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Conjunctivitis-treatment
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-antibiotics-drops/systemic
-antivirals as appropriate -anti-inflammatories as needed -eye irrigations -warm normal saline compresses |
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Corneal disorders-Astigmatism
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astigmatism-irregular or abnormal curvature of cornea
-light rays focus on more than one area of retina, distorting near and distance vision |
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Corneal disorders-Keratitis
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-Inflammation of cornea
-causes infection, hypersensitivity reactions, ischemia, tearing defects, impaired innervation of cornea |
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Nonulcerative keratitis
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-all layers of corneal epithelium remain intact (viral, TB, SLE)
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Ulcerative keratitis
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-tissue destruction and ulceration of cornea (bacterial conjunctivitis)
-corneas blood flow is low so it's hard to heal |
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Corneal disorders-Ulcer
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-local necrosis
-causes-infection, exposure trauma, misuse of contact lenses, herpes viruses -complications-fibrous tissue can form during healing, resulting in scarring and opacity of cornea |
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Corneal disorder-dystophies
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accumulation of cloudy material
-typically inherited -keratoconus-progressive thinning of cornea -typically affects teens and yound adults, usually stabilized -about 20% may require corneal transplant |
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keratoconus
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-progressive thinning of cornea
-typically affects teens and yound adults -usually stabilizes -about 20% may require corneal transplant |
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Eye surgery-Cornea
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-Laser-changes shape of eyes (lasik, prk, lasek, ltk) for refractive errors
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PTK
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-alternative to corneal transplant-diseased corneal tissue is vaporized and surface irregularities are corrected
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Corneal disorders-corneal surgery
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-usually done as outpatient
-eye patch for 24 hours -minimize exposure to sources of infection |
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Lamellar keratoplasy
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-superficial layer of cornea is removed and replaced with a graft
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Penetrating keratoplasy
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-a button or full-tickness of cornea is removed and replaced by donor tissue
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Nursing care of post-op eye surgery patient
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-assess dressing for bleeding, drainage
-maintain patch or shild as ordered -place in semi-fowler's on unaffected side as tolerated -assist pt to avoid coughing, sneezing, or straining if possible -assess and medicate prn for pain -approach pt on unaffected side -place personal articles and call light within reach -admin eye drops as ordered -admin anti-emetic medication as ordered |
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How do you assess for potential complications for a post-op eye surgery patient?
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-increased pain/drainage from affected eye
-hemorrhage w/ blood in anterior eye chamber -flashes of light, floaters, sensation of curtain being drawn over eye (retinal detachment) -cloudy appearance (corneal edema) |
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Marginal blepharitis
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-disorder of the eyelid
-inflammation of glands and lash follicles on eyelid margins -caused by staph or seborrhea (dandruff) |
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Hordeoleum
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-stye
-usually a staph abscess -internal or external lid margin |
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Chalazion
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-a granulomatous cyst or nodule of the lid
-temp/perm right on eyelid |
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Entropion
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-inversion of the lid margin
-related to aging process, infection -can lead to corneal irritation and scarring -eyelashes invert and scrape cornea |
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Extropion
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-eversion of lid margin
-related to aging -can be caused by Bell's Palsy-facial nerve paralysis -can cause infection/scarring of cornea -eyelids flip out |
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Causes of eye burns
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-chemicals
-explosions -flash burns -UV ray |
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Symptoms of eye burns
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-pain
-partial/complete loss of vision -possible bleeding -possible extrusion of eye contents |
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Hyphema; and examples
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-caused by trauma
-bleeding into the anterior chamber of the eye -if the highly vascular uvea is disrupted by blunt force, hemorrhage mayoccur and fill anterior chamber -eye pain, decreased visual acuity, seeing a red tint |
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orbital blowout fracture
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-orbital contents can herniate into underlying maxillary sinus
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nursing care of the eye trauma patient
-chemical burns -irrigation |
-chemicals-immediate priority flushing w/ NS
-water may be used if NS is not available -flush from inner to outer canthus -morgan lens Irrigation; eyelid everted to remove material from conjunctival sac -a topical anesthetic may be used |
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Penetrating Wounds, nursing priorities
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-protect eye from further injury
-decrease pain -no pressure an eye -do not attempt to remove obj -paper cup/shield over affected eye -patch unaffected eye -may be ordered Diamox to decrease ICP (osmotic diuretic) |
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Uveitis causes and symptoms
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-causes; idiopathic, autoimmune, infections, parasites, trauma
-symptoms; pupillary constriction, erythema around limbus (edge), eye pain, photophobia |
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Cataracts Pathophysiology
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-can be congenital or acquired (trauma), 2ndary to inhaled or systemic corticosteroids
-lens fibers and prteins change and degenerate -lens may also yellow, affecting color discrimination |
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Immature cataract
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-when only a portion of the lens is affected (periphery)
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Mature cataract
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-opacification (clouding) of entire lens
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Cataract manifestations
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-tend to occur bilaterally unless related to trauma
-one generally matures more rapidly than the other -light rays are scattered as they pass through clouded lens -if mature, pupil may appear cloudy gray or white |
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Intraocular lens (IOL) implant
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-for cataracts
-an artificial lens to replace the diseased lens of the eye is placed in the posterior capsule behind the iris |
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Intracapsular cataract extraction (ICCE)
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entire lens and its surrounding capsule removed-rarely done today
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Extracapsular cataract extraction (ECCE)
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-the anterior capsule, nucleus, and cortex of lens removed, and posterior capsule is left intact
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Glaucoma symptoms, risk factors,
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-symptoms are narrowing of visual field
-age is primary risk factor -increased in hispanic and african american persons |
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Primary glaucoma
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-most common in adults over age 60
-congenital |
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secondary glaucoma
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-infection/inflammation of eye, cataract, tumor, hemorrhage, trauma
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Glaucoma pathophysiology
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-aqueous humor produced in ciliary body posterior capsule pupil anterior chamber outflow or aborption through trabecular meshwork and Canal of Schlemm
-when absorption or outflow are disturbed, IOP increases injury to optic nerve |
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Open Angle Glaucoma
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-angle refers to the angle formed at the point where iris meets cornea in eye's anterior chamber
-also called chronic simple, most common in adults, cause is unknow -flow of aqueous humor through trabecular meshwork and Canal of Schlemm is relatively obstructed -generally affects both eyes, through pressures may be different in each eye |
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Anterior Angle
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between iris and cornea is normal (open angle)
-however, flow of aqueous humor through |
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Angle Closure Glaucoma
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-also called narrow angle or closed angle
-less common 5-10% -becuase of corneal flattening orbuldging of iris into anterior chamber -when the lens thickens during accommodation or iris thickens during pupillary dilation, the angle can close completely |
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What does Angle closure bock?
Does it effect one or two eyes? when do episodes usually occur? |
-abrupt blockage of trabecular meshowork and Canal of Schlemm, abrupt in IOP
-typically unilateral but incidence in one eye increases risk of occurrence inother eye -episodes may occur in situations that cause pupil to dilate (darkness, emotional stress) |
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What meds are are used for the treatment of Angle Closure glaucoma?
Symptoms? |
-no eye drops or OTC medications unless prescribed
-avoid meds that have mydriatic (pupil dilating) effect-atropine or other anticholinergics -severe eye and face pain, malaise, aN/V, seeing colored halos around lights, abrupt decrease in visual acuity, pupil may be fixed |
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Tonometry
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diagnosic tool for glaucoma
-contact or noncontact |
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Fundoscopy
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-diagnosic tool for glaucoma
-visual inspection w/ an ophthalmoscope -shows pallor and increase in size and epth of optic cup on optic disc |
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Gonioscopy
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-diagnosic tool for glaucoma
-measures depth of anterior chamber -differentiates open from closed -angle |
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Medications for glaucoma
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-adreneric agonist-reduce production of aqueous humor
-beta blockers-reduce production of aqueous humor -carbonic anhydrase inhibitiors-lower IOP -prostaglandin analogs-relax ciliary muscle and increase outflow of aqueous humor |
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What is age-related macular degeneration (ARMD)
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-macula area of retina that provide sharp central vision, receives light from center of visual field
-gradual degeneration of macula |
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Age related macular degeneration risk factors
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-age
-smoking -race -possible genetics (caucasians) |
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Age related macular degeneration-non-exudative (dry)
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-more common
-gradual, begins w/ accumulation of drusen deposits that gradually enlarge and become more numerous -pigment epithelium detaches in small areas and becomes atrophic, interfering with sensory function of macula -may progress to exudative |
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Age related macular degeneration-Exudative (wet)
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-characterized by formation of new, weak blood vessels in the space between the choroid (vascular layer of the ye) and the retinal (neurosensory layer)
-these new vessels leak and elevate the retina from the choroid, causing vision distortion -with significant or repeated bleeding episodes, scar tissue forms, and central vision is permanently lost |
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Diagnosis of age related macular degeneration
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-Amsler grid
-Fluorescein angiogram-pictures taken as dye passes through blood vessels of retina; detects leaks |
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Treatment of ARMD
-dry -wet |
dry-in early or intermediate stages slowed by high dose antioxidants and zinc (vit C,E, A, Zn, Copper)
wet-laser or photodynamic therapy, |
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nonproliferative diabetic retinopathy
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-venous capillaries of eye dilate and develop microaneurysms which leak and cause retinal edema or small ruptures within retina
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Proliferative diabetic retinopathy
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large areas of retinal ischemia occur and neovascularization occurs, spreading rapidly over the inner surface of the retina and into the vitreous body
-new vessels leak fluid and protein retinal edema and hemorrhage into vitreous humor -vessels may become fibrous and cause retinal detachment |
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Symptoms of separation of retina from choroid
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-floaters
-spots -flashes of light -blurred vision -progressive decrease in vision -sensation of curtain or veil across field of vision |
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Cryotherapy
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treatment for separation of retina from choroid
-super cooled probe or laser photocoagulation -these create an area of inflammation and adhesion to "weld" retina to choroid |
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scleral buckling
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-treatment of retinal detachment
-an indentation or fold created in sclera, bringing choroid into contact w/ retina -contact maintained w/ a local implant on sclera or an encircling strap or buckle |
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pneumatic retinopexy
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-air injected into vitreous cavity. Pt positioned so that the air bubble pushes the detached part of the retina into the choroid
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Laser for retinal detachment
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-creates a bond between retinal and choroid
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Retinitis Pigmentosa
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-hereditary degenerative disease
-retinal atrophy and loss of retinal function -rod cells degenerate at periphery of retina -areas of degeneration and cell death expand, causing vision to narrow and central vision to be lost |
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Retinitis pigmentosa symptoms
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-difficulty w/ night vision (even in childhood)
-progress to slow loss of visual fields, photophobia and disrupted color vision -may be blind by age 40 -currently no effective tx -low vision aids, couseling may be helpful |
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How does HIV effect the eyes?
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-retinopathy
-kaposi's sarcoma -cytomegalovirus (CMV) retinitis -corneal ulcers |
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Enucleation
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-caused by traum, infection, glaucoma, intractable pain, malignancy
-conjunctiva and eye muscles sutured onto an implant at time of surgery -pressure dressing for 24-48 hrs -most common complications are hemorrhage and infection |
