Visual Pathway Lesions

Question 1

Which fields correlate with which fibres?

Answer 1

-Nasal fibres = Temporal field
-Temporal fibres = Nasal field
-Superior fibres = Inferior field
-Inferior fibres = Superior field

Question 2

Questions to ask to localise the lesion

Answer 2

-Bitemporal (pre chiasmal) vs homonymous (post chiasmal) hemianopia
-Symmetrical (congruous) vs asymmetrical (incongruous) field loss
=More congruous means closer to occipital cortex

Question 3

Types of hemianopias

Answer 3

-Complete homonymous hemianopia = Occipital lobe lesion
-Superior quadrantanopia = Temporal lobe lesion
-Inferior quadrantanopia = Parietal lobe lesion
-Bitemporal hemianopia = Chiasmal lesion (pituitary tumour)

Question 4

Common visual pathway lesions

Answer 4

-Central Scotoma (retinal)
-Monocular Vision Loss (optic neuritis, optic glioma)
-Bitemporal hemianopia (pituitary adenoma, hypothalamic glioma)
-Contralateral homonymous hemianopia (temporal lobe lesions)
-Contralateral superior quadranopia (parietal lobe lesions)
-Homonymous hemianopia with macular sparing (posterior cerebral artery infarction)