ND - Brain Lesions Causing Visual Field Defects - Week 2 Flashcards

1
Q

Define homonymous.

A

Same side

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2
Q

List three possible locations of a lesion if it is chiasmal.

A

Chiasm
Optic tract
Lateral geniculate nucleus

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3
Q

List three possible locations of a lesion if it is post-chiasmal.

A

Parietal lobe
Occipital lobe
Other

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4
Q

List the four descriptors that a visual field loss of brain origin needs.

A

Side (R/L)
Nature (Homonymous/bitemporal/nasal)
Congruity (similarity)
Type of defect - hemianopia/quadrantanopia etc

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5
Q

What are VF defects in the arcuate region called (isolated)? What about if they are joined to BS?

A

If isolated, Bjerrum scotoma
Otherwise is called arcuate if joined to BS

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6
Q

What can early loss of superficial GCs lead to in terms of ONH appearance?

A

Gives a steep cup with a notch paracentral to Bjerrum scotoma

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7
Q

What can early loss of deep GCs lead to in terms of ONH appearance?

A

Gives a honeycomb and saucerised cup appearance

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8
Q

What does a VF defect involve if it respects the horizontal midline?

A

It involves the RGCs

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9
Q

What do altitudinal VF defects usually indicate for and where?

A

Ischaemia of one pole of the ONH

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10
Q

Can a banana VF defect be ONH or retina or both?

A

Could be either

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11
Q

True or false
Defects at or beyond the chaism will affect VF in both eyes.

A

True

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12
Q

What does a bowtie atrophy indicate the presence of?

A

A lesion in the contralateral optic tract involving crossed retinal fibres nasal to the fovea.

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13
Q

Are individuals with bitemporal hemianopia symptomatic? Explain.

A

Total chiasmal VF hemi-defect can give a hemi-field slide due to the loss of fusion (such as with hyper/eso/exophoria), and this can manifest habitual heterophoria

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14
Q

Where is the defect for a pie in the sky VF?

A

Post-chiasmal - temporal lobe

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15
Q

Where is the defect for a pie on the floor VF?

A

Post-chiasmal - parietal lobe

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16
Q

Define the Riddoch phenomenom. What kind of lesions can it occur in?

A

Perfecption of movement but loss of form
Can occur in occipital lesion

17
Q

Define cortical blindness. What happens to the artery involved?

A

Total blindness due to bilateral occipital lobe lesions
It infarcts the basilar artery

18
Q

Do pupils react normally in cortical blindness? What about their ERG/VER responses?

A

Pupil responses are fine
ERG is fine
VER is abnormal

19
Q

Can individuals with cortical blindness have motion perception?

A

Yes but residual

20
Q

Do individuals with cortical blindness present with a normal fundus exam?

A

Yesd

21
Q

Is hallucination possible with cortical blindness? Explain.

A

Yesd, they may have visual percepts (this is CBS) and deny blindness.
They hallucinate - Anton’s syndrom.

22
Q

Describe the procedure to test for cortical VF loss. What does indicate for? What can happen with chronic cases?

A

Amsler grid
Indicates for scotoma
Cortical filling occurs with chronic cases

23
Q

What two things is simultaneous confrontation good for and not good for?

A

Good
Screening and testing large peripheral defects
Sensitivity
Not good
Retinal or optic lesions
Small defects