Optic Neuropathies

Question 1

Name the common optic neuropathies (3)

Answer 1

-Anterior ischaemic optic neuropathy
-Angle-closed glaucoma
-Optic neuritis

Question 2

What is arteritic anterior ischemic optic neuropathy (AAION)?

Answer 2

-Sudden vision loss with disc swelling that occurs in temporal arteritis (aka giant-cell arteritis).
=Occurs in 15-20%
=Damage to the blood vessels supplying the optic nerves leads to insufficient blood supply to the nerve and subsequent optic nerve fibre death
-RAPD
-Visual field defect

Question 3

Investigation in AAION

Answer 3

-Elevated erythrocyte sedimentation rate (ESR)
-Elevated C reactive protein (CRP)
-Elevated platelet count (thrombocytosis)
-Temporal artery biopsy

Question 4

Treatment of AAION

Answer 4

-IV methylprednisolone
-Followed by at least 18 months tapering course of oral prednisolone with bone and gut protection

Question 5

Describe Non-arteritic AION

Answer 5

-Most common form of ischaemic optic neuropathy
-Caused by infarction of the short posterior ciliary arteries that supply the anterior portion of optic nerve head
-Presents with acute unilateral painless vision loss (usually inferior eye) accompanied by sector or diffuse optic nerve oedema
=RAPD, visual field defect, optic nerve swelling

Question 6

Systemic diseases causing decreased perfusion to optic nerve head (due to microvascular compromise)

Answer 6

-Hypertension
-Diabetes
-Hypercholesterolemia
-Smoking

Question 7

Management of NAAION

Answer 7

-Exclude giant cell arteritis
-Cardiovascular work up
-No effective treatment for vision loss and disc oedema
-Effective management of cardiovascular risk factors

Question 8

What is optic neuritis?

Answer 8

-Demyelination affects the optic nerve
-Strongly associated with MS
-Not everyone who experiences optic neuritis goes on to develop further symptoms of MS, but a significant proportion do
=Optic disc swelling
=Peri-orbital pain, worse on movement
=Unilateral loss of VA with central scotoma
=Colour desaturation
=RAPD

Question 9

Causes of optic neuritis

Answer 9

-MS (complete or partial loss of vision in 1/2 eyes) MRI demyelinating lesions
-Idiopathic
-Hereditary (Leber’s disease)
-Para infectious (measles, mumps, chickenpox, whooping cough, glandular fever)
-Infectious (cat scratch fever, TB, Lyme disease, cryptococcal meningitis in AIDS patients)
-Autoimmune (sarcoidosis, SLE, PAN)

Question 10

Treatment of optic neuritis

Answer 10

-MRI with gadolinium contrast (brain and orbits)
-Visual function usually spontaneously improves over 2-3 months
-IV methylprednisolone?