3e. Gaze Defects

Question 1

What are gaze defects?

Answer 1

Abnormalities in the ability to move both eyes together in a particular direction of gaze

Question 2

What lesion causes a horizontal gaze palsy?

Answer 2

Lesion in the paramedian pontine reticular formation (PPRF) or abducens nucleus

Question 3

What is the gaze defect seen in internuclear ophthalmoplegia (INO)?

Answer 3

Inability to adduct the affected eye with nystagmus in the abducting eye

Question 4

Which condition causes vertical gaze palsy?

Answer 4

Lesion in the dorsal midbrain (e.g., Parinaud’s syndrome)

Question 5

What is the hallmark of one and a half syndrome?

Answer 5

Horizontal gaze palsy in both directions with only abduction in the contralateral eye preserved

Question 6

What is the cause of supranuclear gaze palsy?

Answer 6

Lesions above the level of cranial nerve nuclei, often seen in progressive supranuclear palsy (PSP)

Question 7

Which artery infarct is classically associated with internuclear ophthalmoplegia?

Answer 7

Pontine branches of basilar artery

Question 8

What is the main feature distinguishing nuclear from supranuclear gaze palsy?

Answer 8

Reflex eye movements (like doll’s eye) are preserved in supranuclear lesions

Question 9

What is the most common cause of INO in young adults?

Answer 9

Multiple sclerosis

Question 10

What is the most common cause of INO in elderly?

Answer 10

Brainstem infarction