Ophthalmology Flashcards
(33 cards)
Immune privilege
traumatic injury to the eye, an area of the body that has inherent immune privilege can lead to the release of previously sequestered antigens that T cells recognize as foreign; leads to subsequent inflammation and blindness in both the injured and noninsured eye
ophthalmologic finding of Kayser-Fleischer ring
strongly associated w Wilson’s disease; seen most frequently in pts w neuropsychiatric complications; basal ganglia atrophy is typically present in these pts
Herpes zoster ophthalmicus
caused by reactivation of varicella-zoster virus in the ophthalmic division of the trigeminal nerve (CN V1); characterized by painful, dermatomal rash and ocular involvement (acute keratitis, corneal ulceration); most commonly occurs in elderly and immunosuppressed pts
age-related cataracts
cataracts is characterized by progressive opacification of the lens w chronic loss of visual acuity; aging and environmental exposures contribute to cataract formation by inducing nuclear sclerosis, photo-oxidative damage to lens crystalline and osmotic injury
anticholinergic effects on 1st gen antihistamines
in addition to blocking histamine receptors, 1st gen antihistamines (chlorpheniramine, diphenhydramine) have antimuscarininc, anti-alpha adrenergic and anti-serotonergic properties; anticholinergic effects on the ocular ciliary muscles impair accommodation and cause blurring of vision for close objects
Congenital CMV infection
5% of women develop primary CMV infections (mononucleosis-like illness) during pregnancy; there is a risk of vertical transmission to the fetus; the most common eye-related complication is chorioretinitis
anisocoria
asymmetric pupils
pt w anisocoria
asymmetric pupils is caused by a lesion in the ocular parasympathetic (constriction) or sympathetic (dilation) pathways
Open-angle glaucoma
characterized by progressive loss of peripheral vision from elevated intraocular pressure; timolol and other non selective beta blockers work by diminishing the secretion of aqueous humor by ciliary epithelium
Retinitis pigmentosa
a genetic condition resulting in progressive dystrophy of retinal pigmented epithelium and photoreceptors; pts present w progressive night blindness and loss of peripheral vision due to early loss of rods, which are highly metabolically active; funduscopic exam shows dark pigments deposited in a bone-spicule pattern in addition to retinal vessel attenuation and optic disc pallor
Retinoblastoma
retinoblastoma is the most common ocular tumor of childhood; occurs due to a germline mut that affects the RB tumor suppressor gene on chr 13; a “second hit” is acquired that leads to Rb due to two inactivated Rb genes; these pts have increased risk of secondary tumors, especially osteosarcomas
Retinopathy of prematurity
the pathogenesis involves initial down regulation of proangiogenic factors (ex: VEGF) due to HYPERoxia following delivery; increased metabolic demand causes relative retinal hypoxia which stimulates a pathological increase in VEGF; leading to aberrant vessel formation; neonatal O2 supplementation increases the risk in premature infants
OTCs that trigger acute angle-closure glaucoma (ACG)
acute ACG may be precipitated by topical and systemic meds that cause pupillary dilation such as alpha-adrenergic agonist and drugs w strong anticholinergic effects; results in rapid rise in intraocular pressure that typically causes severe eye pain, conjunctival injection and corneal edema (haziness)
central retinal artery occlusion presents w sudden painless and permanent monocular blindness; funduscopic exam reveals a pale retina and a “cherry-red” macula
Atropine induced acute angle-closure glaucoma (ACG)
atropine is indicated for the tx of bradycardia as it decreases vagal influence on the SA and AV nodes; a common side effect is increased interocular pressure; may precipitate acute closed-angle glaucoma in susceptible individuals
CN III
provides innervation to many of the extra ocular muscles, parasympathetic innervation to the pupil and somatic innervation of the elevator palpebrae superioris; dysfxn of CN III leads to a characteristic triad of a “down and out”, an efferent pupillary defect and ptosis
Internuclear ophthalmoplegia is a disorder of impaired horizontal gaze caused by a lesion in the MLF; the affected eye (ipsilateral to the lesion) is unable to adduct while the c/l eye is able to abduct; convergence and the pupillary light reflex are preserved because these pathways bypass the MLF
Corticosteroids associated cataracts
cataracts are related primarily to chronic photo-oxidative injury; most pts w cataracts first develop symptoms at age >60 but exposure to systemic or ophthalmic glucocorticoids can cause cataracts at an early age; other causes of premature cataract formation include DM, ocular trauma and external radiation exposure
CMV retinitis is the most common cause of ocular disease in pts w untreated AIDS who have CD4 <50/mm3; dx is made by funuscopy which typically reveals yellow-white, fluffy retinal lesions near the retinal vessels w associated hemorrhage; tx w ganciclovir is required to prevent blindness
Optic radiations
inferior optic radiations travel through the temporal lobe in the Meyer loop; they carry information from the inferior retina, which covers the superior visual field; temporal lobe lesions can result in c/l homonymous superior quadrantanopia
Glaucoma meds
Topical prostaglandins (ex: latanoprost) increase outflow of aqueous via the uveoscleral pathway and are the preferred tx for open-angle glaucoma
flame-shaped retinal hemorrhage
severe HTN in retinal pre capillary arterioles causes endothelial disruption, leakage of plasma into the arteriolar wall and fibrinous necrosis; necrotic vessels can then bleed into the nerve fiber layer, which can be seen on examination as dot- or flame-shaped hemorrhages
myopia (nearsigntedness)
myopia is a refractive error in which the focal point of an image falls anterior to the retina due to increased anterior-posterior diameter of the eyes; pts have difficulty seeing objects at a distance and have normal near vision
age-related macular degeneration (AMD)
wet age-related macular degeneration is characterized by retinal neovascularization due to increased VEGF levels; pts typically have acute vision loss and metamorphosis w funduscopy showing a grayish-green sub retinal membrane and/or sub retinal hemorrhage; tx includes smoking cessation and VEGF inhibitors therapy (ex; ranibizumab, bevacizumab)
