4- visual defects

Question 1

what causes scotoma

Answer 1

localised defect in retina

Question 2

what causes monocular blindless

Answer 2

damage to optic nerve

Question 3

what causes contralateral homonymous hemianopia (5)

Answer 3

• damage to optic tract
• damage to lateral geniculate
• damage to optic radiations
• non vascular damage to the occipital lobe (without macula sparing)
• occlusion of posterior cerebral artery (macula sparing_

Question 4

what causes contralateral homonymous inferior quadrantanopia

Answer 4

damage to superior optic radiations (parietal lobe)

Question 5

what causes contralateral homonymous superior quadrantanopia

Answer 5

damage to inferior optic radiations (optic nerve)

Question 6

where are the temporal and nasal fibres located

Answer 6

temporal- outside

nasal- inside

Question 7

which fibres cross in the optic chiasm

Answer 7

nasal fibres decussate, temporal fibres remain ipsilateral

Question 8

describe the optic tract and what it contains

Answer 8

optic chiasm > lateral geniculate nucleus > primary visual cortex

• ipsilateral temporal fibres
• contralateral nasal fibres

Question 9

what are the two optic radiations

Answer 9

• superior optic radiation (Baum’s loop). in parietal lobe. carries superior quadrant fibres
• inferior optic radiation (Meyers loop) in temporal lobe contains inferior quadrant fibres.

Question 10

where does the optic tract run to

Answer 10

the lateral geniculate nucleus

Question 11

where does the optic radiations run to

Answer 11

the primary visual cortex

Question 12

where are temporal and nasal visual fields detected by>

Answer 12

temporal visual fields- nasal fibres

nasal visual fields- temporal fibres

Question 13

what radiations are responsible for the inferior and superior quadrants of vision

Answer 13

superior quadrant- inferior radiations (temporal lobe)

inferior quadrant- superior radiations (parietal lobe)