Ophtho 2 Flashcards
Papilledema
Optic disc swelling (usually b/l) due to high ICP (secondary to mass effect sometimes)
Enlarged blind spot and elevated optic disc with blurred margins seen on exam
Cataracts
Painless, often bilateral opacification of lens leading to reduced vision
Risk factors: Age, smoking, EtOH, excessive sunlight, prolonged steroid use, classic galactosemia, galactokinase deficiency, diabetes (sorbitol), trauma, infection
Glaucoma
Optic disc atrophy with characteristic cupping (thinning of outer rim of optic nerve head versus normal
Usually with high IOP and progressive peripheral visual field loss
Open angle glaucoma
Associated with age, being black, family history
Painless, more common in US
Primary - cause unclear
Secondary - blocked trabecular meshwork from WBCs (uveitis), RBCs (vitreous hemorrhage), retinal elements (retinal detachment)
Closed angle glaucoma
Primary - enlargement or forward movement of lens against central iris (pupil margin) leading to obstruction of normal aqueous flow through pupil. Fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular network.
Secondary - hypoxia from retinal disease (diabetes, vein occlusion) induces vasoproliferation in iris that contracts the angle
Chronic closure - often ASx with damage to optic nerve and peripheral vision
Acute - True emergency. Increased IOP pushes iris forward leading to angle closing abruptly. Very painful, red eye, sudden vision loss, halos around lights, rock hard eye, frontal headache. Do not give epinephrine bc of its mydriatic effect
Uveitis
Inflammation of uvea (iritis aka anterior uveitis, choroiditis aka posterior uveitis).
May have hypopyon (accumulation of pus in anterior chamber) or conjunctival redness. Associated with systemic inflammatory disorders (sarcoid, RA, juvenile idiopathic arthritis, HLA-B27 associated conditions)
Miosis
Constriction, parasympathetic
1st neuron - EW nucleus to ciliary ganglion via CN 3
2nd neuron - short ciliary nerves to pupillary sphincter muscles
Pupillary light reflex
Light in either retina sends a signal via CN 2 to pretectal nuclei in midbrain that activates bilateral EW nuclei. Pupils constrict bilaterally (consensual reflex)
Result - illumination of 1 eye results in bilateral pupillary constriction
Mydriasis
Dilation - sympathetic
1st neuron - hypothalamus to ciliospinal center of Budge (C8-T2). Synapse is in lateral horn.
2nd neuron - Exit at T1 to superior cervical ganglion (travels along cervical sympathetic chain near lung apex, subclavian vessels). Synapse is in superior cervical ganglion.
3rd neuron - plexus along internal carotid, through cavernous sinus. Enters orbit as long ciliary nerve to pupillary dilator muscles. Sympathetic fibers also innervate smooth muscle of eyelids (minor retractors) and sweat glands of forehead and face
marcus gunn pupil
APD - due to optic nerve damage or severe retinal injury.
Reduced bilateral pupillary constriction when light is shone in affected eye related to unaffected eye.
Test with swinging flashlight
Horner Syndrome
Sympathetic denervation of face
1) Ptosis - slight drooping of eyelid. superior tarsal muscle
2) Anhidrosis - absence of sweating and flushing of affected side of face
3) Miosis - pupil constriction
Associated with lesion of spinal cord above T1 (Pancoast tumor, Brown Sequard, late stage syringomyelia)
Any interruption results in Horner
EOMs
LR6SO4R3
How to test each EOM
Obliques go opposite. L SO and IO tested by looking R. IO tested looking up.
SO depression best tested when eye is adducted
SR - test by looking up and abducted
LR - test by abducting
MR - test by adducting
SO - look down and adduct
IO - look up and adduct
CN 3 damage
CN3 has both motor (central part of nerve) and parasympathetic (peripheral) components.
Motor output to ocular muscles is affected primarily by vascular disease (diabetes: glucose to sorbitol) due to lower diffusion of oxygen and nutrients to the interior fibers from compromised vasculature that resides on outside of nerve. Signs = ptosis, down and out gaze
Para output - fibers on periphery are affected first by compression (PCom aneurysm, uncal herniation). Signs = diminished pupillary light reflex, “blown pupil,” often with down and out gaze
CN 4 damage
Eye moves upward, particularly with contralateral gaze and head tilt toward the side of the lesion (problems with going down stairs, may present with compensatory head tilt in the opposite direction
