2. Retinal Artery Occlusion (RAO)

Question 1

Role of arteries and where do they originate from?

Answer 1

Arteries bring blood to the eye and originate from carotid artery in the neck.

Question 2

What are the 4 pathogenesis of RAO?

Answer 2

1. Embolism
2. Thrombosis
3. Vasospasm
4. External pressure

Question 3

What causes an emboli?

Answer 3

Plaque caused due to high pressure due to diabetes, high BP, cholesterol. Emboli travels through blood.

Question 4

What is thrombosis and what causes it?

Answer 4

Blood clot could be transient or long lasting. Causes: Diabetes, high BP, clotting disorders.

Question 5

What is vasospasm and what causes it?

Answer 5

Contraction of arterial walls, causes interruption of blood supply.

Question 6

4 risk factors of occlusion?

Answer 6

1. Inflammatory conditions- increase viscosity of blood.
2. Peripheral vascular disease
3. Migrane
4. Thrombophlic disorders

Question 7

What is atherosclerosis?

Answer 7

Narrowing of blood vessels due to fatty deposits, mostly found where the blood vessels are splitting (carotid arteries).

Question 8

Atherosclerosis is associated with?

Answer 8

Ocular ischemic syndrome (where blood flow is limited).

Question 9

4 types of retinal artery occlusions?

Answer 9

1. Amarosis fugax
2. Branch retinal artery occlusion (BRAO)
3. Central retinal occlusion (CRAO)
4. Cilioretinal artery occlusion

Question 10

What is Amarosis fugax, and how does it represent?

Answer 10

It is identified using px history, what the px describes. Transient vision loss, curtain of vison- vision recovery occurs in the same way as vision is lost. Diagnosis is determined by history. Lasts for a couple of minutes, if more then that it is not temporary in nature.

Question 11

How does BRAO present?

Answer 11

White patch, scotoma, VA will depend on location, usually asymptomatic, no hemorrhages. On OCTA- No flow.

Question 12

Central retinal artery occlusion presentation?

Answer 12

Sudden and complete painless loss of vision, pale disc, pale and odematous retina, cherry red spot on macular, very thin blood vessels. Dense RAPD, no flow on angio. No swelling of disc.

Question 13

What causes the cherry red spot in CRAO?

Answer 13

Middle of the fovea has no blood vessels, however, the red spots indicates blood flow happening through choriocapillaris.

Question 14

Urgency for treatment for RAO? and does vision recover?

Answer 14

Urgent, risk of vision recovery is low.

Question 15

Acute treatment for RAO?

Answer 15

1. Supine position- reduce arterial pressure in the eyes.
2. Ocular massage
3. Anterior chamber paracentesis
4. Medically reducing IOP using Mannitol.
5. Rebreathing in paper bag.
6. Hyperosmotic agents
7. Yag laser, thrombolysis

Question 16

Systemic management of RAO?

Answer 16

1. Refer to stroke team
2. Address general cardiovascular risk factors
3. Anti-platelets therapy.

Question 17

Referal for acute onset?

Answer 17

Emergency

Question 18

Ongoing care for BRAO?

Answer 18

3 months review of fundus, check systemic management of px, check risk of neovasc.

Question 19

What is neovascular iris (NVI)?

Answer 19

New vessels growing on the iris, move the the TBM and shut it down when pressures are high.

Question 20

Thrombus likely to happen in the vein, why?

Answer 20

Because blood flow is slower

Question 21

Vein occlusions rarely caused by emboli, why?

Answer 21

Veins are connected to capillaries, it is very unlikely that an emboli will make its way through the capillaries then block a vein.