Ophthalmology Flashcards
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)
Presbyopia and skin wrinkles
both are age-related changes; presbyopia occurs due to denaturation of structural proteins with the lens, leading to loss of lens elasticity which can result in improved vision in pts w mild myopia; decreased synthesis and increased breakdown of collagen and elastin contribute to the development of skin wrinkles
bluish discoloration to vision
phosphodiesterase 5 inhibitors (ex: sildenafil, tadalafil) can cause a transient bluish discoloration to vision
lesion in sympathetic pathway anisocoria
pupillary symmetry (anisocoria) is caused by a lesion in the ocular parasympathetic (constriction) or sympathetic (dilation) pathways in this pt, pupillary asymmetry increase in a dim room indicating that the smaller right pupil is unable to dilate due to a lesion in the R oculosympathetic pathway
idiopathic intracranial HTN (pseudotumor cerebri)
presents in young obese women w daily HA (which worsens during the valsalva maneuver), b/l symmetric papilledema and transient visual disturbances; increased intracranial pressure compresses the optic nerves, resulting in impaired axoplasmic flow and optic disc edema
Candida chorioretinitis & endophthalmitis
Candida endophthalmitis typically occurs due to hematogenous dissemination to the choroid layer in the setting of fungemia; most cases arise in hospitalized pts w indwelling central catheters; pts usually have unilateral eye floaters and progressive vision loss
AMD
age-related macular degeneration (AMD); a scotoma is a discrete visual field defect; central scotomas are often caused by AMD that leads to the deposition of drusen clustered around the macula
age-related macular degeneration (AMD)
a scotoma is a discrete visual field defect; central scotomas are often caused by AMD that leads to the deposition of drusen clustered around the macula
diabetic retinopathy
chronic hyperglycemia in pts w diabetes can lead to increased permeability and arteriolar obstruction in retinal vessels; the resulting ischemia stimulates production of vascular endothelial GF and other angiogenic factors leading to neovascularization; complications include retinal hemorrhage, retinal detachment and vision loss
diabetic retinopathy
chronic hyperglycemia in pts w diabetes can lead to increased permeability and arteriolar obstruction in retinal vessels; the resulting ischemia stimulates production of vascular endothelial GF and other angiogenic factors leading to neovascularization; complications include retinal hemorrhage, retinal detachment and vision loss
