What are 5 important causes of a swollen optic disc?
- Optic neuritis
- Papilloedema (must be bilateral)
- Malignant hypertension
- Arteritic anterior ischaemic optic neuropathy (arteritic AION)
- Non-arteritic AION
What is optic neuritis?
Demyelinating inflammation of optic nerve
What are 6 clinical features associated with optic neuritis?
- Retrobulbar pain esp on eye movement, associated with globe tenderness
- Disc may not be swollen
- RAPD
- Red desaturation
- Central scotoma on field testing
- May have transient neurological symptoms
What is the long-term risk associated with optic neuritis?
Risk of developing MS
What is papilloedema?
Optic disc swelling that is caused by increased intracranial pressure
Can papilloedema be unilateral?
No
What are 5 clinical features of papilloedema?
- Transient visual obscurations
- May have splinter haemorrhages, exudates, cotton wool spots and retinal folds near the disc
- Enlarged blind spots
- Gradually progressive field loss - generalised constriction
- Eventual atrophic changes
What is arteritic AION?
Loss of vision caused by damage to the optic nerve as a result of insufficient blood supply due to inflammatory infarction of posterior ciliary artery
What are 5 clinical features of AAION?
- Temporal headache assoc with:
- Jaw claudication
- Weight loss
- Myalgia
- Raised ESR and CRP
What is the immediate treatment of AAION?
Urgent treatment with high dose steroids
How long does someone with AAION need to be treated?
2 years
What investigation needs to be done within a week of starting treatment for AAION?
Temporal artery biopsy
What is non-arteritic AION?
Non-inflammatory infarction of posterior ciliary artery, leading to damage to the optic nerve and loss of vision
What are the levels of ESR in NAION?
Not raised
Do you get associated systemic symptoms with NAION?
No
What condition are 50% of people with NAION associated with?
Hypertension
What is optic atrophy?
Death of retinal ganglion cell axons which comprises the optic nerve - leads to optic nerve damage anywhere along the path from the retina to the lateral geniculate
=end stage eye disease
What are 5 clinical features of optic atrophy?
- Vision loss
- Visual fields affected
- Subtle damage may lead to loss of contrast or colour vision
- RAPD
- Optic disc pallor (reflects absence of small vessels in disc head)
Which extraocular eye muscles are affected by 3rd nerve palsy?
- Medial rectus
- Inferior rectus
- Superior rectus
- Inferior oblique
- Levator palpebrae superioris
What are the 3 features of 3rd nerve palsy?
- Eye points down and out
- Ptosis
- +/- Dilated pupil (efferent defect)
Why does the eye point down and out in 3rd nerve palsy?
Superior oblique and lateral rectus are spared so unopposed
Which extraocular eye muscle is affected in IVth nerve palsy?
What does it lead to?
Superior oblique
Eye unable to look down and in on affected side
Which extraocular eye muscle is affected in VIth nerve palsy?
What does it lead to?
Lateral rectus
Inability to abduct, eye may drift medially due to pull of medial rectus
What is the innervation of orbicularis oculi and what is its function?
Temporal and zygomatic branches of the facial nerve (CN VII)
Function is to close eyelids
