Flashcards in Ophthamology Deck (40)
What is the definition of hyperopia?
eye too short for refractive power of cornea and lens --> light focused behind retina
What is the definition of myopia?
eye too long for refractive power of cornea and lens --> light focused in front of retina
What is the definition of astigmatism?
abnormal curvature of cornea resulting in different refractive power at different axes
What is the definition of presbyopia?
decrease in focusing ability during accommodation d/t sclerosis and decreased elasticity
What is the definition of uveitis?
inflammation of anterior urea and iris, with hypopyon (sterile pus), accompanied by conjunctival redness
What diseases are associated with uveitis?
sarcoid, RA, juvenile idiopathic arthritis, TB, HLA- B27 - assoc. conditions
What is the definition of retinitis?
retinal edema and necrosis --> scarring
What diseases are associated with retinitis?
often VIRAL (CMV, HSV, HZV)
What clinical findings are seen with central retinal artery occlusion?
acute, painless monocular vision loss
retina cloudy with attenuated vessels and "cherry-red" spot at the fovea
What is the definition of retinal vein occlusion?
blockage of central or branch retinal vein d/t compression from nearby arterial atherosclerosis --> retinal hemorrhage and edema in affected area
What are the 2 types of diabetic retinopathy?
Diabetic retinopathy = retinal damage d/t chronic hyperglycemia
Type 1: non-proliferative - damaged capillaries leak blood --> lipids and fluid seep into retina --> hemorrhages and macular edema. Tx: blood sugar control and macular laser
Type 2: proliferative - chronic hypoxia --> new blood vessel formation with resultant traction on retina Tx: peripheral retinal photocoagulation, anti-VEGF injections
What structure of the eye collects aqueous humor that flows through the anterior chamber?
What structure in the eye collects aqueous humor from the trabecular meshwork?
Canal of Schlemm
What are findings of glaucoma?
usually with increased intraocular pressure (IOP) and progressive peripheral visual field loss
What risk factors are associated with open angle glaucoma?
What is the pathogenesis of primary closed/narrow angle glaucoma?
enlargement or forward movement of lens against central iris --> obstruction of normal aqueous flow through pupil --> fluid builds up behind iris --> peripheral iris pushed against cornea, impeding flow through trabecular meshwork
What is the pathogenesis of secondary closed/narrow angle glaucoma?
hypoxia from retinal disease (e.g. diabetes, vein occlusion) --> vasoproliferation in iris that contracts angle
Very painful, sudden vision loss, halos around lights, rock-hard eye, and frontal HA are associated with what emergent condition?
acute closed angle glaucoma
What are risk factors for cataracts?
prolonged corticosteroid use
What is papilledema?
optic disc swelling d/t increased intracranial pressure
What physical exam findings will you see with papilledema?
enlarged blind spot
elevated optic disc with blurred margins seen on fundoscopic exam
What can be observed with CN III damage?
eyes look DOWN and OUT
loss of accommodation
What can be observed with CN IV damage?
eyes move UPWARD
often have problems going down the stairs, may present with compensatory head tilt in the opposite direction
What can be observed with CN VI damage?
medially directed eye that cannot abduct
What is the nerve path for miosis?
1st neuron: Edinger-Westphal nucleus to ciliary ganglion via CN III
2nd neuron: short ciliary nerves to pupillary sphincter muscles
What is the nerve path for mydriasis?
1st neuron: hypothalamus to ciliospinal center of Budge (C8-T2)
2nd neuron: exit at T1 to superior cervical ganglion (travels along cervical sympathetic chain near lung apex, subclavian vessels)
3rd neuron: plexus along internal carotid, through cavernous sinus; enters orbit as long ciliary nerve to pupillary dilator muscles
How does illumination in 1 eye result in bilateral pupillary constriction?
light in either retina sends a signal via CN II to pretectal nuclei in midbrain --> activates bilateral Edinger-Westphal nuclei --> bilateral pupil constriction
What is a Marcus Gunn pupil?
afferent pupillary defect where you see decreased bilateral pupillary constriction when light is shone in affected eye relative to unaffected eye.
Caused by damage to OPTIC NERVE or SEVERE RETINAL INJURY
With damage to CN III, what physical findings will you see?
a "down and out" gaze