Eye Exam Flashcards
refractive errors
hyperopic
myopic
hyperopia
farsightedness?? eye is shorter than normal, or cornea and lens refract too weakly?? the image falls behind the retina
hyperopia correction
glasses, contact lens, refractive surgery
use of convex (converging) lens
increase natural refracting power so image is focused on retina
what is required for vision to be clear?
image to be projected precisely on the retina
cornea and lens refract light
emmetropia
myopia
nearsightedness
when eye is longer than normal or cornea and lens focus too strongly
image falls in front of retina
myopia correction
glasses, contact lenses, refractive surgery
use of concave (diverging) lens
decrease natural refracting power so image is focused on retina
astigmatism
due to dift corneal or lens curvatures
results in multiple focal points, causing blurry vision
like a footballl?? dift curves ?? require own cylindrical lens to correct refractive error
presbyopia
eyes lens become more rigid so its cant change shape as easliy to focus
normal after 40, corrected with focals/reading glasses
or can be corrected with contact lenses or treated surgically to achieve monovision
photoretractive keratoectomy
laser sculpts cornea?? either flattens it for myopia or steepens it for hyperopia
LASIK
laser assisted in situ kertaomileusis
microkeratome cuts a thin, hinged flap of corneal tissue, folded back, laser is used to reshape cornea, then flap laid back
which defects respect the vertical meridian?
defects of visual pathway
features of pituitary tumor
bitemptoral hemianopia and diminished libido are common presentign symptoms
when adenomas become large enough, they exert mass effect on optic chiasm
growth hormone secreting pituitary adenomas are slow growing and go undiagnosed for years
defects respecting the horizontal meridian help to localize the pathology to where?
retina or optic nerve (glaucoma)
what is glaucoma?
what are 3 major parts?
disease of optic nerve
leading cause of blindness in US
leading cause of IRREVERSIBLE vision loss in af ams in US
? visual loss, pressure in eye, optic nerve damage
progression of cupping/damage of optic nerve
risk factors of glaucoma
increasing age, african ancestry, family history
what is metamorphopsia?
lines on grid are wavy/missing on amsler grid (helps to asses 10 degrees of visual field?? macula function)
age related macular degeneration
most common cause of irreversible vision loss over age of 65 in US
macular tissue deteriorates, lead to mild to severe CENTRAL vision loss, NOT TOTAL BLINDNESS
dry from/atrophic age related macular degeneration
most common form
IRREVERSIBLE VISION LOSS
vitamin C and E, zinc, copper oxide, and beta carotene may slow progression
why shouldnt you perscirbe beta kerotine to people who smoke?
increase risk of lung cancer
AMD: wet form (exudative)
occurs when abnormal blood vessels under the retina leak fluid, blurring central vision
IRREVERSIBLE VISION LOSS
new injectable anti?VEGF meds achieve high success in vision preservation
on angiogram, you have ring around macula (shows blood vessels growing where they shouldnt)
can get distortion from scarring
pharmacologic dilation
due to scopolamine?? produces mydriasis (dilation) and cyclopegia (paralysis of ciliary muscle, lack of accomodation by blocking muscaranic Ach receptors)
scopolamine patches are used to prevent motion sickness
leukocoria
white pupil
importnat clinical finding in children due to potential for amblyopia, blindness, death (unilateral)
sign of retinoblastoma
retinoblastoma
present with 3 signs:
what else are they at risk for?
most common primary intraocular malignancy in childhood, fatal without tx
present with leukocoria, strabismus, painful red eye
2 hit hypothesis?? RB tumor suppressor gene
increased lifetime risk for sarcomas, brain tumors, melanoma, lung and bladder CA
retinoblastoma tx:
enucleation, multiagent chemo, cryotherapy, laster, plaque brachytherapy, external beam radiation
remisison rate >90%
strabismus
constant misalignment of two eyes (object not visualized simultaneously by both fovea)?? cause double vision (binocular diplopia, but if you close 1 eye you see straight)
amblyopia
vision loss that is NOT correctable by glasses in an otherwise healthy eye
REVERSIBLE if detected and treated early (before 5)
at least half pts w/ amblyopia have strabismus
can also be caused by asymmetric refractive error and form?deprivation (from ptosis)?? dont stimulate visual pathway
tx for amblyopia
lazy eye”?? wear a patch to force brain to recognize bad eye”
which 4 abnormalities of eye/ eye lid that lead to vision loss?
ptosis (eye drooped)
proptosis (pushing forward of eye)
entropion (eye lid rolling inward)
ectropion (eye lid rolling outward)
blepharitis
types (3)
symptoms
chronic inflammation of lid margin
types: staphylococcal, seborrheic (skin dz that creates flaky/scaly skin), combo
symptoms: decreased vision, foreign body sensation, burning/mattering
blepharitis tx
lid hygiene: commercially available lid scrub kid, cleanse iwht non irritating shampoo at roots of lashes
AB ointment?? bacitracin or neosporin
meibomitis
tx:
inspissated meibomian glands oily and foamy tear film commonly seen in ocular rosacea tx: hot compresses and eyelid massge, DOXYCYCLINE precursors to styes
stye (acute)
types
causes
external hordeolum?? staph abscess of lash follice, gland of Zeis or Moll, tender swelling/pustule at lid margin, may discharge through skin
internal hordoleum?? staph abscess of meibomian glands, tender swelling within tarsal plate, may discharge through skin or conjuncitva? if untreated, can get meningitis
chronic: chalazion
meibomian cyst
painless, roundish, firm lesion within tarsal plate
may rupture through conjunctiva and cause granuloma
usually need to drain them
blepharoptosis
due to which eye muscle?
upper eyelid margin rests at lower position than is normal
usually due to stretching of levator aponeurosis
can be due to CN 3 palsy
subtle ptosis present on affected side in pts with horners
horners syndrome
characterized by ptosis, miosis, anhidrosis (no sweating)
only 2mm of ptosis bc muellers muscle (sympathetic) is still working
pancoast tumor: tumor at apex of lung?? can affect cervical sympathetic plexus causing a horners
why is it especially important to recognize red eye after surgery?
always considered a possible threat for irreversible vision loss!
what 8 red eye disorders are a threat for irreversible vision loss?
perforating trauma corneal infection scleritis hyphema (blood in eye) iritis acute glaucoma orbital cellulitis ednophthalmitis
which 8 red eye disorders are non threatening for irrerversible vision loss?
subconjunctival hemorrhage hordeolum (stye) chalazion blepharitis dry eyes conjunctivitis cornea abrasions allergic rxn
how do red eyes from allergy present?
from hordeolum, chalazion?
allergies: itching
hordeolum, chalazion?? localized to lid tenderness
how do red eyes from lid, conjunctival, corneal disorders, foreign body, trichiasis, dry eye present?
scratchiness, burning
how do red eye due to corneal abrasions, scleritis, iritis, acute angle closure glaucoma present?
deep, intense pain
how do red eye due to corneal abrasion, iritis, acute glaucoma present?
photophobia
what presents with halo vision?
corneal edema (acute glaucoma, contact lens overwear)
purulent discharge?? cause?
clear watery discharge??
stringy, white mucous??
bacterial
viral (periauricular lymphadenopathy)
allergy
how do you treat neonatal chlamydial conjunctiva?
caused by chlamydia trachomatis (most commonly STI in US)
newborn colonized during passage through birth canal, develops few days?weeks after birth
all newborns receive erythromycin eye drops prophylactically
MUST TREAT systemically to prevent pneumonia
neonatal conjunctiva:
on day 1, due to __
day 2?5:
day 5?14:
1: chemical (silver nitrate)
2?5: neisseria gonorrhea
5?14: chlamydia trachomatis
what does chalamydia trachoma cause?
common source of vision loss in 3rd world areas
causes adult chlamydial keratoconjunctivitis (corneal pannus, cicatricial entropion (eyelid folds inward)
tx: topical tetracycline
MUST treat systemically?? PO tetracycline, azithromycin, erythromycin
adenoviral conjunctivitis
nonenveloped iscosahedral DNA virus (produce spikes that extend from capsid)
adevnoviral conjunctivitis: vision loss, watery discharge, HIGHLY contagious, usually bilateral, palpable preauricular lymph node
URI, sore throat, fever in prior week
SURFACES MUST BE DISINFECTED WITH BLEACH?? alcohol will not eliminate?? contagious!
what can dry eye cause?
vision loss (insufficient tear film or inadequate quality of tears)
more common with aging
symptoms: blurry vision, excess tearing, foreign body/gritty feeling
tears have IgA, IgG, lactoferrin, growth factors?? all good
sjogrens syndrome
women
keratoconjunctivitis sicca, xerostomia (dry mouth), otehr CT or autoimmune disease (RA)
autoimmune destructionof lacrimal and salivary glands
increased lifetime risk for lymphoma
what should you NEVER prescribe for corneal abrasion/pain control?
topical anesthetics
why is it important to recognize corneal infections?
what is a main cause?
can cause irreversible vision loss
bacterial keratitis: expanding oval, yellow?white dense stromal infiltrate
fungal keratitis
frequently preceded by ocular trauma with organic matter (plant or veg)
get greyish white ulcers
slow progression
DO NOT GIVE TOPICAL STEROIDS
acanthamoeba keratitis
contact lens wearers at risk (ESP in hot tubs!)
perineural infilrate
small, pathcy anterior stroma infiltrate
severe pain
rx: chlorhexidine and or pHMB (pool cleaner!)
what should you not give with herpes simplex epithelial keratitis?
NO topical steroids!
subconjunctival hemorrhage
usually asymptomatic or minimal irritaiton
can be from eye rubbing, cough/strain, trauma, HTN, bleeding
check BP and meds, give artificial tears
if TRAUMA?? considered threat for permanent vision loss
how do chemicals work in eye?
acid precipitates quickly?? battery fluids, chem lab
alkali continues to penetrate and coagulates tissue (can progress)?? lye, household cleaners, fertilizers
immediate irrigation is essential!
cataract
clouding of lens
vision can look like looking through frosty/fogged window
LEADING cause of vision loss worldwide, but are reversible
aging, diabetes, previous surgery, prolonged steroids cause cataracts
symptoms of acute angle closure glaucoma
severe ocular pain frontal headache blurred vision with haloes n/v mid dilated irregular pupil, cloudy cornea, conjunctival hyperemia
optic nerve edema
reversible vision loss
papilledema” when bilateral
optic nerve cupping
loss of retinal nerve fiber layer which results in gradual concentric enlargement and deepenign of cup
irreversible vision loss
what does diabetic retinopathy show?
precedes development of diabetic neuropathy
LEADING cause of irreversible vision loss in US under 65
tx: panretinal laser tx: laser used to place hundreds of light burns in retina, stimulates new vessels to shrink (reduce metabolic need)
central retinal artery occlusion
pts present with acute onset of monoocular visual loss
retinal edema (cherry red spot due to lack of nerve fiber layer in fovea)
cause of irreversible vision loss
tx involves lowering IOP
big 6 sources of vision loss
refractive errors, gluacoma, macular degeneration, amblyopia, cataract, diabetic retinopathy
