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Neurology > Ophthalmology > Flashcards

Ophthalmology Flashcards

1
Q

What is the optic chiasm?

A

The part of the brain where some of the optic nerves cross over as they go from the eyes to the brain

It is an X shape

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2
Q

Where is the optic chiasm?

A

It is at the bottom of the brain immediately below the hypothalamus

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3
Q

Which nerves cross over at the optic chiasm and which don’t?

A

The nerves coming from the nasal side of each retina cross over

The nerves coming from the temporal sides of the retina don’t

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4
Q

What is bitemporal hemianopia?

A

Partial blindness where there is loss of vision in the outer half of the right and left visual field

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5
Q

What causes bitemporal hemianopia?

A

A lesion or compression at optic chiasm

Affects the crossing over of the nasal retinae nerves

The visual impulse from both nasal retina are affected leading to inability to view the temporal vision

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6
Q

On which part of the retina does images from the temporal visual field fall?

A

On the nasal retinae

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7
Q

What are ‘incongruous field defects’?

A

Problems with vision that do not match up exactly between the two eyes

So more of the visual field is lost in one eye than the other

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8
Q

What would a lesion on the optic nerve (i.e. before the optic chiasm) cause?

A

Monocular visual loss

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9
Q

Describe the journey of a nerve impulse from the eyeball to the visual cortex?

A

R or L Eyeball

R or L Optic nerve

Optic chiasm:
- decussation of nasal retinal nerves

R or L Optic tract

R or L thalamus: lateral geniculate nucleus

R or L thalamus

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10
Q

What would a lesion on the optic chiasm cause?

A

Bitemporal hemianopia

Loss of vision in temporal fields

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11
Q

What does homonymous mean?

A

Same problem on both sides (eyes)

Homonymous = congruous

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12
Q

What does congruous mean?

A

Same problem on both sides (eyes)

Congruous = homonymous

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13
Q

What would a person with higher cortical visual dysfunction suffer with?

A

Difficulty describing pictures

Difficulty recognising faces

Difficulty drawing a clock

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14
Q

Which part of the thalamus is vision processed in?

A

Lateral geniculate nucleus

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15
Q

What is scotoma?

A

Area of partial alteration in the field of vision

Such as weird zigzags, blind spots etc.

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16
Q

What is papilloedema?

A

Swollen optic disc

When you look at someone’s eye using an ophthalmoscope it appears white and jagged in the centre

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17
Q

What is papilloedema a sign of?

A

Raised inter-cranial pressure

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18
Q

What is diplopia?

A

Double vision

19
Q

What is cranial nerve III called?

A

Oculomotor

20
Q

What does cranial nerve III do in terms of the eye?

A

Innervates the extra-ocular muscles

Controls:

  • eyelid elevation
  • elevation, depression, adduction of the eye
  • pupillary constriction
  • lens accommodation
21
Q

What are the extra-ocular muscles?

A

Superior rectus
Lateral rectus
Medial rectus
Inferior rectus

Superior oblique
Inferior oblique

22
Q

Which muscles move the eye up and down?

A

Superior and inferior rectus

23
Q

Which muscles move the eye side to side?

A

Medial and lateral rectus

24
Q

What does the superior oblique muscle do to the eye?

A

Internal rotation
Depression of eye
Abduction: lateral movement

25
Q

Which nerve innervates the superior oblique muscle?

A

Trochlear (IV)

26
Q

Which nerve innervates the inferior oblique muscle?

A

Oculomotor (III)

27
Q

What does the inferior oblique muscle do to the eye?

A

External rotation
Elevation of eye
Adduction: medial movement

28
Q

What is extorsion and intorsion?

A

Another name for the rotation of the eye internally or externally

29
Q

Which eye muscles does the oculomotor nerve innervate?

A

Medial, inferior and superior rectus

Inferior oblique

30
Q

What eye muscles does the trochlear nerve innervate?

A

Superior oblique

31
Q

What eye muscles does the abducens nerve innervate?

A

Lateral rectus

32
Q

Which nerve supplies the lateral rectus?

A

Abducens

33
Q

Which nerve supplies the superior oblique?

A

Trochlear

34
Q

What would happen to they eye if there were a lesion on the oculomotor nerve?

A

Lateral squint, eye shifts laterally because there is no medial rectus pulling it back

Ptosis due to loss of oculomotor control which elevates eyelid

35
Q

What is ptosis?

A

Drooping of eyelid

36
Q

What would happen to the eye if there were a lesion on the trochlear nerve?

A

Eye elevated due to loss of superior oblique muscle depressing the eye

Medial squint - eye shifts medially due to loss of superior oblique muscle to pull the eye back laterally

37
Q

What would happen to the eye if there were a lesion on the abducens nerve?

A

Eye doesn’t move laterally

Medial squint since no lateral rectus to pull it back

38
Q

What is a ‘palsy’?

A

Paralysis, weakening

39
Q

What is nystagmus?

A

Rhythmic to and fro oscillations of the eyes

40
Q

What causes nystagmus?

A

Can be congenital

Or acquired

  • stroke
  • MS
41
Q

What does sympathetic nervous system do to the pupil?

A

Dilates pupil

42
Q

What does parasympathetic nervous system do to the pupil?

A

Constricts pupil

43
Q

What does a problem with:
- parasympathetic
- sympathetic
nervous systems cause in the pupils?

A

Parasympathetic problem = pupils will dilate

Sympathetic problem = pupils will constrict

44
Q

What is a relative afferent pupillary defect?

A

One pupil contracts with light

One pupil dilates with light, vision is poorer in this eye

Neurology (23 decks)

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