RETINAL ARTERY OCCLUSION

Question 1

What do we call transient monocular blindness?

Answer 1

Amaurosis fugax

Question 2

What are the causes of amaurosis fugax?

Answer 2

Thromboembolic event

Carotid stenosis

Vasculitis: GCA

Vasospasm

Haematological: Sickle cell disease, polycythaemia

Postural arterial hypertension

Question 3

What clinical features might help you differentiate between embolic transient retinal artery occlusion and non-embolic transient retinal artery occlusion such as vasospasm?

Answer 3

Embolic - black loss of vision (‘negative’ visual symptom)

Non-embolic - Grey / white / patchy loss of vision (‘positive’ visual symptom)

Question 4

How do we treat amaurosis fugax caused by an embolic event?

Answer 4

Aspirin

Warfarin if AF

Question 5

How do we treat amaurosis fugax caused by carotid stenosis?

Answer 5

Carotid endarterectomy if over 70% and less than 100% occlusion

Question 6

How do we treat amaurosis fugax caused by vasospasm?

Answer 6

Nifedipine

Question 7

What are the causes of central retinal artery occlusion?

Answer 7

Embolus - carotid, cardiac

Thrombosis - 65% are arteriosclerotic

Giant cell arteritis

Collagen vascular disease - SLE

Hyperviscosity - polycythaemia, myeloma

Question 8

What clinical feature might point to a diagnosis of giant cell arteritis with central retinal artery occlusion?

Answer 8

Bilateral

Question 9

What are the clinical features of retinal artery occlusion?

Answer 9

Sudden loss of vision

Painless

May have past history of transient visual loss

Relative afferent pupil defect

Pale swollen retina

Cherry red spot (fovea)

Occasional central sparing

Question 10

What investigations should be done in someone who presents with sudden painless visual loss suggestive of central retinal artery occlusion?

Answer 10

ESR - to rule out GCA

Other bloods: CRP, FBC, U&E

BP

Fluoroscein angiogram

VDRL - syphilis

Cardiovascular work up

ERG (electroretinography) - to determine prognosis

Question 11

How do we manage someone who presents with sudden painless visual loss suggestive of central retinal artery occlusion?

Answer 11

Needs immediate treatment to salvage eyesight - under 4 hours:

Ocular massage

IV Acetazolamide 500 mg stat

Anterior chamber paracentesis

Rebreathing CO2 - improves blood flow

If GCA - steroids