Clinical Eye and Ear

Question 1

clinical findings of parasympathetic pupillary changes if afferent limb is damaged; causes

Answer 1

marcus-gunn pupil; less reactivity with swinging light test; causes: stroke in optic nerve, unilateral cataract, optic neuritis

Question 2

causes of efferent limb damage to pupillary light reflex

Answer 2

aneurysm pressing on CN III, cavernous sinus fistula, stroke in midbrain

Question 3

why could a tumor in the apex of the lung cause sympathetic efferent problems?

Answer 3

T1/T2 nerves travel over the apex of the lung

Question 4

defect of optic chiasm causes

Answer 4

bitemporal hemianopsia

Question 5

defect of meyer’s loop in temporal lobe causes

Answer 5

contralteral homonymous superior quadrantanopsia

Question 6

parietal lobe lesion causes

Answer 6

contralteral homonymous inferior quadrantanopsia

Question 7

occipital lobe lesion causes

Answer 7

contralteral homonymous hemianopsia

Question 8

posterior cerebral artery occlusion causes

Answer 8

contralateral homonymous hemianopsia that has macular sparing (since small branch of MCA goes to tip of occipital lobe in some ppl ad allows preservation of macular vision)

Question 9

what is prostitute’s pupil, and what causes it?

Answer 9

it accommodates when object is brought near, but does NOT react to light; neurosyphillis

Question 10

the cranial nerves in the midline of brainstem

Answer 10

3, 4, 6, 12 (multiplicants of twelve)

Question 11

clinical appearance of CN III lesion

Answer 11

eye is down and out, complete ptosis, dilated pupil

Question 12

lesions that will cause dysfunction of the 3rd cranial nerve

Answer 12

aneurysms, infarctions of the brainstem or CN III, cavernous sinus lesions, transtentorial herniation

Question 13

clinical appearance of CN IV palsy

Answer 13

diplopia, corrected by leaning to the opposite side of the lesion

Question 14

internuclear ophthalmoplegia results from a lesion in the…./ what causes these lesions?

Answer 14

MLF; MS, brainstem strokes

Question 15

the pathway of conjugate eye movements

Answer 15

moving the eyes left: right frontal lobe, goes to the left PPRF, which gives input to the ipsilateral CN VI nucleus, also sends fibers to the opp CN III via the MLF on opposite side of the brainstem

Question 16

Weber Test: how does conduction deafness present?

Answer 16

air conduction is reduced but bone conduction is relatively enhanced. the sound is perceived better in the bad ear.

Question 17

Weber test: how does sensorineural deafness present?

Answer 17

sound is perceived as louder in the good ear.

Question 18

Rinne test: how sensorineural loss presents

Answer 18

air conduction is greater than bone conduction

Question 19

Rinne test: how conduction deafness presents

Answer 19

bone conduction is greater than air conduction

Question 20

describe the effects of the rotational test

Answer 20

endolymph continues to move in direction of rotation; slow component is ipsilateral, so the nystagmus (fast phase) is contralteral to direction of rotation

Question 21

caloric testing: hot vs cold water

Answer 21

cold water causes contralateral nystagmus, hot water causes ipsilateral nystagmus