Central Retinal Artery Occlusion

Question 1

what are the causes of CRAO?

Answer 1

Endarteritis – GCA
Embolus - (Fibrin, cholesterol, calcific) carotid, heart valve disease
Atherosclerotic – diabetes, HT
Vasospasm
Vasculitis  - polyarteritis nodosa

Question 2

what is CRAO?

Answer 2

Occlusion of the retinal artery – supplies inner neuroretina

Question 3

what are the fundoscopic features of CRAO?

Answer 3

o Pale, swollen retina with cherry red spot

o May be able to see emboli – white platelet, yellow

Question 4

why does CRAO cause a cherry red spot?

Answer 4

Fovea blood supply is from posterior ciliary artery – shines through

Question 5

what are the clinical features of CRAO?

Answer 5

• Sudden painless loss of vision – unliteral
• RAPD – afferent pupillary defect?
• Visual acuity markedly reduced
• Reduction in central and peripheral vision
• a curtain falling across vision

Question 6

what is the management of CRAO?

Answer 6

Only effective if presentation within 12-24hrs
Ocular massage
Paper bag – raised CO2 causes vasodilation
IV Diamox
Anterior chamber paracentesis
Urgent rule out/referral for GCA

Question 7

what is the cause of AION?

Answer 7

o Arteric - GCA

o Non Arteric – typically 45-65, hypermetropia (small crowded optic disc), smoking

Question 8

what is the pathophysiology of AION?

Answer 8

• Optic nerve is damaged if posterior vascular supply to the optic nevre is blocked by inflammation or atheroma - posterior cillary arteries

Question 9

what are the clinical features of AION?

Answer 9

	Painless 
	Symptoms noticed in the morning
	Loss commonly affects the upper of lower visual field 
	Onset subacute
	Monocular and profound in GCA

Question 10

what are the fundoscope features of AION?

Answer 10

Optic nerve swollen, hyperaemic, pale disc later

Question 11

what are the features of GCA?

Answer 11

accompanying symptoms of headache, malaise, jaw tenderness, hip and shoulder pain

Question 12

what is the treatment of AION caused by GCA?

Answer 12

prednisolone

Question 13

what is the treatment of non GCA AION?

Answer 13

no active treatment, addressing risk factors

Question 14

what is Amaurosis Fugax?

Answer 14

temporary occlusion of retinal artery

Question 15

what are the causes of amaurosis fugax?

Answer 15

o Embolic = TIA, cardiac (AF, valves)
o Haemodynamic – GCA, vasospasm
o Ocular – iritis, jeratiits, blepharitis posterior vitreous detachment, closed angle glaucoma, myopia
o Neurologic – optic neuritis, papilledema, MS

Question 16

what are the clinical features of amaurosis fugax?

Answer 16

o Temporary loss of vision – less then 60mins

o Altitudinal defects are often seen “curtain coming down”

Question 17

what are the fundoscopic features of amaurosis fugax?

Answer 17

as RAO, white emboli, cherry red spot, too early for signs?

Question 18

what is the management of amaurosis fugax?

Answer 18

as for TIA – 300mg Aspirin, full work up for underlying cause