Neuro - opthalmology

Question 1

How to test for defects in the optic nerve

Answer 1

RAPD - relative afferent pupillary defect

• swinging light test

Question 2

Causes of afferent pupillary defects

Answer 2

Optic neuritis - younger patients with MS
GCA - older patients generally
Retinal artery occlusion

Trauma
Tumours
Retinal detachment

Question 3

Which ocular muscles does CN III innervate

Answer 3

Superior rectus
Inferior rectus
Medial rectus
Inferior oblique

Question 4

Which ocular muscles does CN IV innervate

Answer 4

Superior oblique

Question 5

Which ocular muscles does CN VI innervate

Answer 5

Lateral rectus

Question 6

3rd cranial nerve palsy presentation

Answer 6

Ptosis - superior levator palpebrae muscle

Down and out position

Binocular diplopia

Dilated pupil

Question 7

Signs of a 3rd nerve palsy

Answer 7

Head tilt

Wrinkles on forehead as lifting frontalis muscle to compensate for the ptosis

Question 8

Causes of a 3rd nerve palsy

Answer 8

Diabetes
HTN

Posterior communicating artery aneurysm - compresses 
Space occupying lesion 
Raised ICP 
Trauma 
GCA 
Congenital 
Demyelinating disease such as MS

Question 9

What condition must be ruled out in a 3rd nerve palsy

Answer 9

Posterior communicating artery aneurysm - MR angiogram

Question 10

Differentials for a 4rd nerve palsy

Answer 10

Myasthenia gravis
Horner’s syndrome
Thyroid eye disease
Internuclear ophthalmoplegia

Question 11

4th nerve palsy presentation

Answer 11

Up and in

Diplopia when reading - vertical biocular diplopia

Question 12

6th nerve palsy presentation

Answer 12

Diplopia when looking to side of affected eye - horizontal binocular diplopia

Question 13

Pathophysiology of papilloedema

Answer 13

Swollen optic nerve head

Question 14

How does papilloedema present

Answer 14

Normal with headache due to raised ICP

May have nausea or vomiting

Question 15

Causes of papilloedema

Answer 15

Raised ICP due to

• space-occupying lesion
• trauma
• haemorrhage
• idiopathic intracranial haemorrhage

Question 16

Risk factors for papilloedema

Answer 16

High BMI
Women
Contraceptive pill

Question 17

What investigation should be done for papilloedema

Answer 17

MR venogram - rule out dural venous sinus thrombosis

Question 18

Optic neuritis presentation

Answer 18

Defect on RAPD
Decreased red saturation
Larger blind spot
Pain with eye movements

Question 19

Treatment of optic neuritis

Answer 19

Steroids

Question 20

Causes of optic neuritis

Answer 20

Autoimmune demyelination - MS, sarcoidosis

Infection

Question 21

History for neuro ophthalmology

Answer 21

Eye defect

Limb weakness
Speech issues 
Walking and gait 
Nerve sensations 
Headache

Question 22

Branches of the oculomotor nerve and what they supply

Answer 22

Superior branch - levator palpebrae superioris and superior rectus

Inferior branch - IR, MR, IO

Question 23

Pupil involvement of a 3rd nerve palsy

Answer 23

Indicative of a compressive aetiology as the outer nerve fibres innervate the ciliary body with parasympathetic innervation

Question 24

Investigations for a third nerve palsy

Answer 24

Orthoptic assessment 
Bloods - FBC, U+Es, LFTs, CRP
BP 
CT head - SOL
MRA - PCA aneurysm 
Biopsy - GCA 
MRI - MS

Question 25

Treatment for 3rd nerve palsy

Answer 25

Treat underlying cause 
Manage HTN/ diabetes 
Prisms - diplopia 
Ptosis prop - if only seeing through one eye 
Strabismus surgery

Question 26

Which nerve is most likely to be affected by trauma

Answer 26

CN IV - longest route intracranially as leaves brainstem backwards