Systemic Disease and the Eye

Question 1

Cardinal features of neuro-ophthalmic disease?

Answer 1

Eye movement defects - double vision

Visual defects - visual acuity, field loss

Question 2

Potential causes (surgical sieve) of neuro-ophthalmic disease?

Answer 2

Vascular disease

Tumours (primary and secondary), i.e: space-occupying lesions

Trauma

Demyelination

Inflammation/infection

Congenital abnormalities

Question 3

Ix for neuro-ophthalmic disease?

Answer 3

Blood tests (for glucose, cholesterol, etc)

Imaging:
• MRI scan

Question 4

Causes of ocular motility defects?

Answer 4

CN III palsy

CN IV palsy

CN VI palsy

Inter-nuclear ophtalmoplegia

Supra-nuclear ophthalmoplegia

Question 5

Presentation of CN VI palsy?

Answer 5

Presents with lateral rectus palsy of the affected side, i.e: when asked to abduct 1 eye and then the next, the affected one cannot abduct

Question 6

Causes of CN VI palsy?

Answer 6

Microvascular (most common cause)

Raised ICP

Tumour

Congenital

Question 7

How to differentiate CN VI palsy causing lateral rectus abduction failure from raised ICP compressing the CN VI?

Answer 7

Check for papilloedema; if this is present, it is a surgical emergency

(CN VI can be compressed as it passes over the petrous part of the temporal bone; raised ICP can also cause nausea)

Question 8

Presentation of CN IV palsy?

Answer 8

Allows depression in adduction; this will not occur if there is a palsy

Question 9

Why do children with a CN IV palsy often present with a head tilt?

Answer 9

To compensate for the double-vision resulting from the weakness of the superior oblique (incyclo-torsion is weak), patients characteristically tilt their head down and to the side opposite the affected muscle

Question 10

Causes of a CN IV palsy?

Answer 10

Congenital decompensated

Microvascular

Tumour

For bilateral palsy, closed head trauma is the main cause

Question 11

Clinical features of a bilateral CN IV palsy?

Answer 11

Torsion

Depression of the chin

Question 12

Cause of a bilateral CN IV palsy?

Answer 12

Blunt head trauma

Question 13

Muscles supplied by CN III?

Answer 13

Medial, inferior and superior rectus

Inferior oblique

Sphincter pupillae

Levator palpebrae superioris

Question 14

Presentation of a CN III palsy?

Answer 14

Ocular position is down and out

Question 15

Causes of a CN III palsy?

Answer 15

Microvascular

Tumour

Aneurysm

MS (demyelinating disorders)

Congenital

Question 16

MAIN CAUSE to consider with a painful CN III palsy that involves the pupil and why?

Answer 16

ANEURYSM of the circle of Willis (posterior communicating artery), until proven otherwise; this is because the fibres run adjacent to the nerve and can be compressed by an aneurysm

If the pupil is not involved, it is likely to be microvascular and will not involve the pupil

Question 17

Function of the inter-nuclear pathways?

Answer 17

Eyes must act together, e.g: looking left:
• Left eye looks left
• Right eye looks left

At the same time and speed

Question 18

What is inter-nuclear ophthalmoplegia and how does it present?

Answer 18

Affected eye shows impairment of adduction

When an attempt is made to gaze contralaterally (relative to the affected eye), the affected eye adducts minimally, if at all; the contralateral eye abducts, with nystagmus

Additionally, the divergence of the eyes leads to horizontal diplopia (i.e: when they look to the left, they see 2 images side-by-side)

Question 19

Area that is defective in inter-nuclear ophthalmoplegia?

Answer 19

Injury or dysfunction to the medial longitudinal fasciculus (MLF)

Question 20

Causes of inter-nuclear ophthalmoplegia?

Answer 20

MS

Vascular

Others

Question 21

Visual field defects can arise due to defects in which areas of the optic pathways?

Answer 21

1. Optic nerve (total blindness of ipsilateral eye)
2. Optic chiasm (bitemporal hemianopia)
3. Optic tract (contralateral homonymous hemianopia)
4. Optic radiation (contralateral quadrantonopia)
5. Occipital cortex (contralateral homonymous hemianopia with macular sparing)

As soon as the optic chiasm is reached, both visual fields are affected

Question 22

Aetiology of most neuro-ophthalmic visual defects?

Answer 22

Vascular disease (cerebrovascular accident) - typically >50 years old

Space-occupying lesion (SOL) - tumours usually occur <50 years of age

Demyelination (MS) - typically <50 years of age

Trauma (inc. surgical)

Question 23

Neuro-ophthalmic pathologies affecting the optic nerve?

Answer 23

Ischaemic optic neuropathy

Optic neuritis (commonly caused by MS)

Tumours (rare), including:
• Meningioma
• Glioma
• Haemangioma

Question 24

Types of optic nerve defects?

Answer 24

Either:
• Complete
OR
• Abide the horizontal

Question 25

Presentation of optic neuritis?

Answer 25

Progressive visual loss (unilateral)

Pain behind eye, esp. on movement

Colour desaturation and central scotoma

Question 26

Period of recovery for optic neuritis?

Answer 26

Gradual recovery over weeks-months

Question 27

Complications of optic neuritis?

Answer 27

Can cause optic atrophy

Question 28

Pathologies affecting the optic chiasm?

Answer 28

Pituitary tumour

Craniopharyngioma

Meningioma

Question 29

Treatment of visual loss due to a pituitary tumour?

Answer 29

Visual loss/disturbance is commonly reversed after the tumour is decompressed or removed

Question 30

Pathologies affecting the optic tracts and radiations?

Answer 30

Tumours (primary and secondary)

Demyelination

Vascular anomalies

Question 31

Presentation of optic tract and radiation pathology with visual loss?

Answer 31

Homonomous quadrantonopia with no sparing of the macula

Incongrous (slightly affects one side of fibres more the other)

Question 32

Pathologies affecting the occipital cortex?

Answer 32

Vascular disease (CVA)

Demyelination

Question 33

Presentation of occipital cortex pathology with visual loss?

Answer 33

Homonomous defect with macular sparing

Congruous