Ophthamology Flashcards
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?
immunosuppression
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?
trabecular meshwork
What structure in the eye collects aqueous humor from the trabecular meshwork?
Canal of Schlemm
What are findings of glaucoma?
characteristic “cupping”
usually with increased intraocular pressure (IOP) and progressive peripheral visual field loss
What risk factors are associated with open angle glaucoma?
Increased age
African Americans
family history
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?
old age smoking alcohol excessive sunlight prolonged corticosteroid use classic galactosemia galactokinase deficiency diabetes (sorbitol) trauma infection
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
ptosis
pupillary dilation
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
What is the pathogenesis of retinal detachment?
separation of neurosensory layer of retina from outermost pigmented epithelium –> degeneration of photoreceptors –> vision loss
What is the treatment for retinal detachment?
surgical emergency!
What is the pathogenesis of age-related macular degeneration?
degeneration of macula (central area of retina) –> distortion (metamorphosis) and eventual loss of central vision
What are the two types of age-related macular degeneration?
- Dry (nonexudative, >80%)
2. Wet (exudative, 10-15%)
Deposition of yellowish extracellular material in and beneath Bruch membrane and retinal pigment epithelium (“duress”) and a gradual decrease in vision is characteristic of what eye disease?
DRY age-related macular degeneration
Rapid loss of vision d/t bleeding secondary to choroidal neovascularization is characteristic of what eye disease?
WET age-related macular degeneration
What is the treatment for wet age-related macular degeneration?
anti-vascular endothelial growth factor injections (anti-VEGF) or laser
What nerve track loops around the inferior horn of the lateral ventricle?
Meyer loop
What nerve track takes the shortest path via internal capsule?
Dorsal optic radiation
What is the pathogenesis of internuclear ophthalmoplegia (INO)?
a lesion of the medial longitudinal fasciculus (MLF) results in lack of communication b/t the CN VI nucleus and CN III nucleus –> ultimately, nystagmus of one eye during abduction.
NOTE: convergence of eyes is NORMAL
If a person has right INO, this means which eye is paralyzed?
RIGHT eye
