Visual Pathway

Question 1

What cells of the retina layers give rise to the optic nerve?

Answer 1

Ganglion layer cells (second neuron)

Question 2

What areas does the optic tract project and what is the function of some?

Answer 2

• lateral geniculate nucleus ▶️ cerebral cortex (vision integration)
• superior colliculi ▶️ reflex gaze
• pretectal area ▶️ light reflex
• suprachiasmatic nucleus of hypothalamus ▶️ circadian rhythms

Question 3

Which are the components of accommodation-convergence reaction?

Answer 3

• accommodation
• convergence
• pupillary constriction

Question 4

Cause of open angle glaucoma. Major finding.

Answer 4

• Decrease drainage and reabsorption of aqueous humor into the canal of schlemm
• ⬆️ Intraocular pressure

Question 5

Cause of narrow angle glaucoma. Major findings

Answer 5

• blockade of canal of schlemm
• ⬆️ Intraocular pressure
• acute (painful) or chronic (genetic)

Question 6

Why cortically blind patient could have normally both pupillary light reflex?

Answer 6

Because the reflex doesn’t involve visual cortex

Question 7

Why do you use beta blocker to treat glaucoma?

Answer 7

Decreased aqueous humor production by ciliary body (beta receptor SANS)

Question 8

Why does the lesion at cuneus, lingual or total visual cortex have the macula spare?

Answer 8

Collateral blood supply from middle cerebral artery

Question 9

Cause of unilateral anopia, clinical presentation (total optic nerve affected)

Answer 9

• multiple sclerosis, optic neuritis, central retinal artery occlusion
• blindness in affected eye, consensual (+), direct (-) light reflex, central scotoma

Question 10

Cause of ipsilateral nasal hemianopia? Where is the lesion?

Answer 10

• Internal carotid artery aneurism

- lateral aspect of optic chiasm or optic nerve

Question 11

Cause of hemianopia bitemporal

Answer 11

• pituitary adenoma(begins as superior quadrantanopia)

- craniopharyngioma (begins as inferior quadrantanopia)

Question 12

Cause of homonymous hemianopia? Where is the lesion?

Answer 12

• optic tract lesion

- Vascular

Question 13

Cause of homonymous superior quadrantanopia? Where is the lesion?

Answer 13

• middle cerebral artery occlusion

- Meyer’s loop

Question 14

Cause of homonymous inferior quadrantanopia? Where is the lesion?

Answer 14

• posterior cerebral artery occlusion

- medial optic radiations to cuneus

Question 15

How do you differentiate a lesion of optic tract (or at LGB) vs all optic radiations lesion? What alteration do they yield? Which is more common?

Answer 15

• optic tract ▶️ pupillary reflex suppressed, optic radiations ▶️ pupillary reflex preserved
• homonymous hemianopia
• optic radiations more common

Question 16

How call when you get blindness in some field with intact pupillary reflex?

Answer 16

“Cortical blindness”