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Flashcards in Visual Fields Deck (29)
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1
Q

What is labelled as number 1 on the diagram?

A

Optic nerve

2
Q

What is labelled as number 3 on the diagram?

A

Optic chiasm

3
Q

What is labelled as number 4 on the diagram?

A

Optic tract

4
Q

What is labelled as number 7 on the diagram?

A

Upper right optic radiations

5
Q

What is labelled as number 8 on the diagram?

A

Occipital cortex

6
Q

What visual field deficit occurs due to a complete lesion of the R optic nerve?

A

R eye blindness.

Optic nerve severing –> blindness in ipsilateral eye

7
Q

What visual field deficit occurs due to a lesion of the optic chiasm?

A

Bitemporal hemianopia

8
Q

What visual field deficit occurs due to a lesion of the optic tract?

A

Contralateral homonymous hemianopia

9
Q

What visual field deficit occurs due to a lesion of the optic radiations?

A

Contralateral quadrantanopia (e.g. if upper right optic radiations affected then there would be a left superior quadrantonopia)

10
Q

What visual field deficit occurs due to a lesion of the occipital lobe?

A

Contralateral homonymous hemianopia

Also cortical blindness and visual agnosia

11
Q

What visual field deficit occurs due to a lesion of the parietal lobe?

A

Contralateral inferior homonymous quadrantonopia

12
Q

What visual field deficit occurs due to a lesion of the temporal lobe?

A

Contralateral superior homonymous quadrantanopia

13
Q

What nucleus lies within the optic pathway?

A

The lateral geniculate nucleus

14
Q

Which lobe do the superior field of the optic radiations lie in?

A

Temporal lobe

15
Q

Which lobe do the inferior field of the optic radiations lie in?

A

Parietal

16
Q

How would you want to further investigate a patient with a homonymous hemianopia?

A
  • Examine for ipsilateral hermiparesis
  • Examine for cerebellar signs
  • If right: Test for neglect
  • If left: Test for aphasia
17
Q

What are the causes of a homonymous hemianopia?

A
  • Vascular: Ischaemic or haemorrhagic
  • SOL: Tumour or abscess
  • Demyelination: MS
18
Q

Where is the lesion in a homonymous hemianopia?

A

Retrochiasmatic contralateral to defect

A greater defect indicates a larger lesion or one closer to the chiasm

19
Q

What vascular territories affected by a stroke could cause a homonymous hemianopia?

A
  • MCA- middle cerebral artery
  • PCA- posterior cerebral artery
20
Q

What in the visual pathway does the middle cerebral artery supply?

A

The optic radiations in the temporal and parietal lobes

21
Q

What symptoms would you expect with an MCA stroke?

A
  • Contralateral homonymous hemianopia
  • Hemiparesis
  • Higher cortical dysfunction: neglect, aphasia
22
Q

What does the posterior cerebral artery supply in the visual pathway?

A

The occipital lobe and visual cortex

23
Q

What symptoms would you expect with a posterior cerebral artery stroke?

A
  • Homonymous hemianopia with macula sparing (branch of MCA supplies part of visual cortex)
  • No hemiparesis
  • May have cerebellar signs
24
Q

What are causes of a bitemporal hemianopia?

A
  • Pituitary tumour
    • Compresses from below –> descending visual field loss
    • Prolactinoma, Cushing’s, acromegaly
  • Craniopharyngioma:
    • Compresses from above –> ascending visual field loss
25
Q

What is a craniopharyngioma?

A
  • Benign suprasellar tumour originating from Rathke’s pouch
  • Calcified as arises from odontogenic epithelium
26
Q

What is monocular vision?

A

No vision in one eye

27
Q

Where is the lesion in monocular blindness?

A
  • Proximal to the optic chiasm:
    • Eye itself: Cornea, vitreous, retina
    • Optic nerve i.e. optic neuropathy
28
Q

Causes of a right homonymous upper quadrantonopia?

A

Lesion in left (contralateral) temporal cortex due to:

  • CVA (infarct or haemorrhage)
  • Intracranial tumour
  • Trauma
  • Surgery
29
Q

Causes of a right homonymous lower quantrantanopia?

A

Lesion in left (contralateral) parietal cortex due to:

  • CVA
  • Intracranial tumour
  • Trauma