Cornea, Iris and Lens Flashcards
Corneal arcus senilis
common in elderly
-whitish area around cornea (opacification)
-not pathologic
may be seen in severe hypercalcimia
corneal abrasion
very painful
- typically has history of trauma
- need to use fluoroscene stain, because it is not visible with the naked eye
- superficial, epithelial layer
which CN innervates the cornea?
ophthalmic branch of CN V
corneal ulcer
very painful
long onsetting (a few days)
deep into the stroma
-usually related to an infectious process (herpes)
-opaque and can be seen with the naked eye
hypopyon (hypopion)
pus layers behind the cornea
- corneal ulcer
- iritis
- result of an inflammatory process in the anterior of the eye
corneal scar
opaque patch that is secondary to chronic ulceration (abrasions typically don’t scar)
iritis
inflammation of the iris
- typically very painful
- inflammation extends to the limbus
- associated with other inflammatory conditions (RA, IBS)
hyphema
blood in the anterior chamber
- most common cause is trauma
- will stain to stain
- can cause severe tension in the eye
cataract (peripheral)
opacification of the lens
- common complaint is difficult night vision
- treatment is surgical correction
- more at risk of getting it if you have high exposure to UV lights
- no. 1 cause of blindness world wide
glaucoma
intraocular pressure
-pressure begins in the anterior portion of the eye
open-angle glaucoma
angle of canal is open, but flow through trabecular meshwork is slow (overproduction or poor drainage)
- chronic problem
- treatment, create less aqueous humor or allow more flow
- not painful
- high blood pressure of the eye
closed-angle glaucoma
iris contracts, angle closes and fluid can’t flow out
- acute onset
- painful, red eye
- headache, nausea, vomiting
- mid-dilated fixed pupil
how does glaucoma cause visual loss?
increased pressure in the anterior of the eye over time can compress the retina and optic disc thereby impairing vision
glaucomatous cupping
pressure spreads the optic disc out and you see a big wide optic disc
hirshberg test
test of corneal light reflection
-normally is slightly nasal to the center of the cornea
esotropia
corneal light reflection is positioned lateral to the center
- eye deviates toward the nose
- convergent strabismus
- light reflection looks more lateral
exotropia
corneal light reflection is positioned nasal to the center (lazy eye)
- outward deviation of the eye
- divergent strabismus
- light reflection looks closer to the nose
convergence
when eyes come together to focus on an object coming near
dysconjugate gaze (strabismus)
abnormal alignment of the eye
paralytic strabismus
weakness or paralysis of one or more extraocular muscles (CN lesions)
-can’t be overcome
-
non-paralytic strabismus
imbalance in muscular tone and may be overcome
-generally developmental/congenital
cover/uncover test
can help differentiate between paralytic or non-paralytic strabismus
VI cranial nerve palsy
paralytic strabismus in which patient cannot abduct laterally (can’t look outward)
CN III palsy
paralytic strabismus in which pt has an eye deviated outward all the time
-constant dilation
CN IV palsy
paralytic strabismus in which pt cannot look down and in
-least common
amblyopia
reduced vision in one or both eyes caused by visual deprivation (seen in childhood)
-strabismus or deprivation
nystagmus
repetitive, oscillatory, jerky eye movements
-seen in disorders of labyrinth
-cerebellar disease
-dilantin toxicity
pathology indicated especially when the nystagmus is
-vertical and rotary
normal in extremes of gaze
which are the most common disease states that cause pathology of the retina?
diabetes
hypertension
microaneurysms
small tiny out pouching in retinal vessels
look like red dots
flame hemorrhages
ruptures of aneurysms
shaped like a candle flame
dot/blot hemorrhages
rupture of hemorrhage
pre-retinal hemorrhage
hemorrhages in front of the retina
hard exudates
material exudes into the retinal tissue
- usually lipid and protein material
- looks like yellow dots
- infarcted retinal tissue
- tiny, pinpoint
cotton wool spots (soft exudates)
look like white or yellowish cotton
-infarcted retinal tissue
neovascularization
new vessel formation
-very bad
proliferative retinopathy
has neovascularization
-new vessels are weak and likely to rupture into the vitrous, which will impair vision
background retinopathy
does not have neovascularization, but does have other evidence of retinopathy (cotton wool spots, hemorrhage)
hypertensive retinopathy findings
tapering-artery comes to a point on either side of the vein instead of bein perpendicular
AV nicking-vein stops abruptly on either side of artery (thickening of vessel wall)
AV banking-twisting of the vessels
copper wire artery-develops increased like reflex from being engorged
silver wire artery-portion of narrowed artery becomes opaque, no blood is visible
macular degeneration
degeneration of the macula
- dry type is atrophy with age and time
- presents with drusen (white spots)
- wet type develops edema under the macula and can lift the macula away from underlying structures (more aggressive, but less common)
papilledema
swelling of the optic nerve
- fluid behind the eye or brain tumor
- increased cranial pressure behind the eye
