AVL: Retinal artery occlusion

Question 1

What is retinal artery occlusion?

Answer 1

Acute painless monocular visual loss with retinal ischemia
- Most common in elderly

Question 2

Causes of retinal artery occlusion

Answer 2

1. Vessel wall occlusion
   - Atheroma
   - Arteritis e.g. Giant cell arteritis
2. Embolisation
   - Carotid atheromatous plaque
   - Heart Valve Lesions (Infective Endocarditis)
   - Cardiac Wall Problems (Mural thrombus/ Atrial myxoma)
   - Atrial Fibrillation
3. Clotting disorders

Question 3

Clinical presentation of retinal artery occlusion

Answer 3

Central retina artery occlusion:
- Sudden onset of painless profound monocular visual loss
- 20% of patients have concomitant cilioretinal artery supply to the macular, preserving central vision

Branch retina artery occlusion:
- Partial visual field loss

Hemi-retina artery occlusion

Question 4

Physical examination finding in retinal artery occlusion

Answer 4

• Profound visual loss (Unable to count fingers +/- hand movements)
• Marked RAPD
• Fundoscopy findings

Question 5

Fundoscopy findings of central retinal artery occlusion

Answer 5

• Attenuation of retinal arteries (Thin threads)
• Pale/white retina
• Cherry red spot at macular (due to fovea being supplied by choroidal artery so it will not be ischemic)
• Cholesterol emboli can be seen (hollenhorst plaques) (Just look for presence of emboli)

Question 6

Management of retinal artery occlusion

Answer 6

Emergency
Immediate:
1. Ocular massage
- Repeatedly massaging the globe over the closed lid for 10 seconds with 5-second interludes (release)
- Sudden increase and decrease in IOP can help dislodge the obstructing thrombus
- Dislodge emboli → Restore perfusion to the eye, restore vision

2. Carbogen therapy
   - Breath into a bag (Increase CO2, causing vasodilation so clot can move more easily)
3. IV Acetazolamide - reduce IOP
4. Anterior Chamber Paracentesis
   - Sudden release in pressure to dislodge embolus/ increase ocular perfusion
5. MRI STAT TRO stroke
6. Treat underlying cause
   - eg. Giant cell arteritis and prescribe high dose steroids to prevent loss of vision in subsequent eye

Question 7

Common cause of retinal artery occlusion

Answer 7

Carotid emboli

Question 8

Fundoscopy findings in BRAO

Answer 8

• Wedge-shaped pale focal ischemic retina
• Attenuated blood vessels

Question 9

Types of possible embolus and where they came from

Answer 9

Cholesterol from carotid arteries
Fibrino-platelet from atherosclerotic vessels
Calcific from cardiac valves

Question 10

Non-ocular investigations to do for retinal artery occlusion

Answer 10

Carotid artery U/S
2D echocardiogram
Lipid panel
Exercise stress test
ECG

Question 11

Risk factors of retinal artery occlusion

Answer 11

HTN
DM
HLD
Previous stroke, AMI
Specifically carotid atherosclerosis
Giant cell arteritis
Valvular heart disease (include IE, AF)

Question 12

In BRAO fundoscopy, paler superior half suggests occlusion of which vessel?

Answer 12

Superior temporal branch

(likewise for inferior temporal branch)