Visual field defects

Question 1

Scotoma definition

Answer 1

visual defect in otherwise normal visual field

Question 2

Causes of visual field defects (8)

Answer 2

ischaemia
glioma
meningioma
abscess
AV malformation
drugs e.g. ciclosporin
pituitary tumour
craniopharyngioma

Question 3

Testing visual field defects (3)

Answer 3

finger confrontation as for CN exam

hat pin confrontation to test for scotoma

amsler grids to detect distortion in central vision e.g. macular disease

Question 4

Quadrantinopias (4)

Answer 4

upper=optic radation=parietal lobe>lower quadrantinopia
lower=Meyer’s loop=temporal lobe>upper quadrantinopia
(PITS)

pituitary tumour (from below)>upper quadrantinopia first>bitemporal hemianopia
craniopharyngioma (from above)>lower quadrantinopia first>bitemporal hemianopia

Question 5

Macular input and blood supply (3)

Answer 5

receives input from much of the visual cortex

has collateral blood supply from MCA and PCA.

stroke in PCA on left>right homonymous hemianopia w. macular sparing.