Neuro-ophthalmology

Question 1

Lesions anterior to the lateral geniculate body produce..

Answer 1

Impairment of vision with impaired pupil response

Question 2

Homonymous hemianopia with sensory and cognitive deficits…where’s the lesion?

Answer 2

Parieto-temporal lesion

Question 3

Isolated homonymous hemianopia…where’s the lesion?

Answer 3

Occipital lobe

Question 4

Bitemporal hemaniopia that involves the upper quadrants first indicates compression of the optic chiasm from below…DDx?

Answer 4

Pituitary adenoma, nasopharyngeal carcinoma, sphenoid sinus mucocele

Question 5

Bitemporal hemaniopia that involves the lower quadrants first indicates compression of the optic chiasm from above…DDx?

Answer 5

Craniopharyngioma, third ventricular tumor

Question 6

Causes of incongruous homonymous hemianopia (one eye affected more than the other)

Answer 6

Compression lesion of the optic tract near the chiasm

The ‘incongruous’ defect occurs as a result of rotation of nasal and temporal fibers

Question 7

Lesion producing inferior quandrananopia

Answer 7

Lesion of the optic radiation in parietal fibers

Question 8

Lesion producing superior quandrantanopia

Answer 8

Lesion of the optic radiation in temporal fibers

Question 9

Lesion producing homonymous hemianopia with macular involvement

Answer 9

Lesion involving the pole of the calcarine cortex

Question 10

Adie’s pupil

Answer 10

Pupil constriction to both direct and consensual light is often absent but very slow pupillary constriction occurs with accommodation

When accommodation is relaxed, slow dilatation occurs

Question 11

Diagnosis of Adie’s pupil

Answer 11

Pupillary response to pilocarpine (the tonic pupil will constrict)

Question 12

Possible causes of Horner’s syndrome

Answer 12

Brain stem lesions (tumor [glioma], vascular lesion, syringobulbia), cervical cord lesions (tumor [glioma], syrignomyelia), lesions to anterior roots of C8 and T1 (tumor [neurofibroma], lower brachial plexus injury), cervical sympathetic chain lesion (Pancoast tumor), lesion of ICA (trauma, occlusion/dissection), or lesion of the middle fossa (tumor, granuloma)

Question 13

Distinguishing peripheral and central lesions producing Horner’s syndrome (preganglionic lesions)

Answer 13

Cocaine acts at the adrenergic nerve endings and, by preventing adrenaline uptake, causes pupil dilatation when the lesion is preganglionic

Question 14

Distinguishing peripheral and central lesions producing Horner’s syndrome (postganglionic lesions)

Answer 14

When the lesion is postganglionic, cocaine has little affect because there are no nerve endings on which the drug may act

Question 15

Argyll-Robertson pupils

Answer 15

Small pupils, irregular in shape, which do not react to light but react to accommodation

Question 16

Causes of Argyll-Robertson pupils

Answer 16

Syphilis or any midbrain lesion (neoplastic, vascular, inflammatory, demyelination)

Question 17

Muscle action of superior rectus

Answer 17

Looks up and out

Question 18

Muscle action of inferior rectus

Answer 18

Looks down and out

Question 19

Muscle action of inferior oblique

Answer 19

Looks up and in

Question 20

Muscle action of superior oblique

Answer 20

Looks down and in

Question 21

Location of oculomotor nucleus

Answer 21

The oculomotor nucleus lies in the ventral periaqueductal grey matter at the level of the superior colliculus

Question 22

Two nuclei within oculomotor nucleus

Answer 22

Perlia’s nucleus (parasympathetic) and Edinger-Westphal nucleus (parasympathetic)

Question 23

Action of Perlia’s nucleus

Answer 23

Convergence and accommodation

Question 24

Action of Edinger-Westphal nucleus

Answer 24

Pupil constriction

Question 25

Course of CN III

Answer 25

On leaving the brainstem the nerve passes through the interpeduncular cistern close the the PCOM and runs toward the cavernous sinus

The nerve runs within the lateral wall of the cavernous sinus and then finally through the superior orbital fissure into the orbit

Once in the orbit, it divides into the superior and inferior branches

Question 26

Location of trochlear nucleus

Answer 26

The nucleus lies in the midbrain at the level of the inferior colliculus, near the ventral periaqueductal grey matter

Question 27

Course of CN IV

Answer 27

The nerve passes laterally and dorsally around the central grey matter and decussates in the dorsal aspect of the brainstem in close proximity to the anterior medullary velum of the cerebellum

Emerging from the brainstem the nerve passes laterally around the cerebral peduncle and pierces the dura to lie in the lateral wall of the cavernous sinus

Finally, it passes through the superior orbital fissure into the orbit

Question 28

Findings of a CN IV lesion

Answer 28

Defective depression of the adducted eye

Patient complains of double vision when looking downwards

Head may tilt to the side opposite the weak SO

Question 29

Function of frontal eye field

Answer 29

Origin of fast rapid eye movement - saccadic movement, either voluntary or reflex

Activation results in jerk deviation of the eyes to the opposite side

Question 30

Function of occipital cortex eye field

Answer 30

Origin of slow following - pursuit movement

Activation results in slow movement of the eyes to the ipsilateral side

Question 31

Conjugate gaze deviation that occurs during a seizure

Answer 31

Eyes deviate toward the affected limbs

Indicates an epileptic focus in the frontal lobe contralateral to the direction of eye deviation

Question 32

Conjugate gaze deviation that accompanies a hemiparesis (e.g. stroke) with tonic deviation of the eyes away from the hemiparetic limb

Answer 32

Indicates a lesion in the frontal lobe ipsilateral to the direction of eye deviation

Question 33

Conjugate gaze deviation that accompanies a hemiparesis (eg. stroke) with tonic deviation of the eyes towards the hemiparetic limb

Answer 33

Usually indicates a lesion in the pons contralateral to the direction of eye deviation and results from damage to the paramedian pontine reticular formation (PPRF)

Question 34

Lesions that produce failure of upward or downward gaze

Answer 34

Lesions in the midbrain or pons

Question 35

Disturbed downward gaze alone can occur when…

Answer 35

Periaqueductal (Sylvian aqueduct) lesions

Question 36

Findings of Parinaud’s syndrome

Answer 36

Impaired upward eye movements in association with a dorsal midbrain lesion

Upward gaze and convergence are lost, the pupils may dilate and the response to light and accommodation is impaired

Question 37

Webino syndrome

Answer 37

Bilateral INO

Midbrain lesion characterized by bilateral exotropia and loss of convergence

Question 38

One and a half syndrome

Answer 38

Conjugate gaze palsy to one side and impaired adduction on looking to the other side

Lesion involves the PPRF or abducens nucleus and adjacent MLF on the side of the complete palsy

Question 39

Ocular apraxia

Answer 39

Bilateral prefrontal motor cortex damage will result in loss of voluntary eye movement to command but yet the patient will have full ROM

Question 40

Characteristics of Gradenigo’s syndrome

Answer 40

Forehead pain is accompanied by ipsilateral lateral rectus palsy and a Horner’s syndrome if sympathetic fibers are involved

Question 41

Causes of Gradenigo’s syndrome

Answer 41

Lesions located at the petrous-temporal bone apex (osteitis or meningitis associated with otitis media)

Question 42

Lesion producing unilateral involvement of the lower face, with near normal eye closure

Answer 42

Indicates a contralateral supranuclear lesion

Question 43

Lesion producing unilateral involvement of the entire face with defective eye closure

Answer 43

Indicates an ipsilateral nuclear or infranuclear lesion