Retinal Artery Occlusion- CRAO/BRAO

Question 1

What 2 types of Retinal Artery Occlusion are there?

Answer 1

CRAO

BRAO

Question 2

What is CRAO?

Answer 2

Central Retinal Artery Occlusion

Question 3

What is CRAO/BRAO caused by?

Answer 3

Embolus or thrombus blocking the artery

Question 4

What is CRAO/BRAO commonly caused by?

Answer 4

Mostly Embolus- a glistening yellow cholesterol emboli can be may in retinal artery

Sometimes thrombus

Question 5

What are the risk factors for CRAO/BRAO

Answer 5

HTN, High cholesterol, DM, giant cell arthritis, systemic lupus erythematosis tobacco use

Question 6

What does CRAO/BRAO indicate?

Answer 6

Indicates increased risk of life-threatening cerebrovascular or cardiovascular incident.

Question 7

What are the symptoms of CRAO/BRAO?

Answer 7

Sudden, severe, painless vision loss

Counting fingers to light perception

Field defect common in CRAO-peripheral more likely to recover

Question 8

Why may they still have good VA despite having CRAO/BRAO?

Answer 8

If they have a cillio-retinal artery which 25% of people have and it supplies the macula

Question 9

What are the early signs of CRAO/BRAO?

Answer 9

Cherry red spot at macula

Pale oedematous retina

Arterial attenuation

Emboli may be seen

RAPD

Segmentation

Question 10

Why is there a cherry red spot?

Answer 10

Fovea is supplied by the choroid and the retina is thinnest at the fovea so underlying choroid is seen.

Also the rest of the retina is very pale as it’s blood supply has been shut of so macula looks even more red in contrast

Question 11

What is segmentation?

Answer 11

Blood moves sluggishly in occluded vessels and blood flow may appear segmented (‘boxcarring’ or ‘cattle tracking’)

Question 12

What are the late signs of CRAO/BRAO?

Answer 12

Optic disc atrophy

Arterial attenuation and segmentation

Question 13

Can VA improve after chronic CRAO/BRAO?

Answer 13

VA usually remains markedly reduced despite treatment

Question 14

What is amaurosis fugax?

Answer 14

It can happen after getting CRA/BRAO once the emboli has dislodged.It causes temporary visual loss

Question 15

What are the symptoms of amaurosis fugax?

Answer 15

Sudden monocular loss of vision

Painless

“Like blind coming down”

Clears slowly in reverse direction

Repetitive

Question 16

How do you manage amaurosis fugax?

Answer 16

Refer to G.P. urgently for CVD work up after excluding GCA

Question 17

What is the visual outcome post CRAO/BRAO?

Answer 17

Any spontaneous recovery in vision usually occurs within first 7 days.

In 10% of eyes with a cilioretinal artery supplying the fovea VA returns to 6/7.5 or better in 80% of eyes within 2 weeks.

Retinal or anterior eye neovascularisation may be possible longer term complications.

Question 18

How do you manage patient with CRAO/BRAO?

Answer 18

Send to A&E, call ambulance. Any treatment outside 4 hour window unlikely to improve vision. If vision loss has occurred within last 24 hours, phone casualty immediately.

Ask px to lie flat to raise pressure of ophthalmic artery

Ocular massage may help to dislodge the embolus – press on eye with heel of hand (10 sec on, 10 sec off for 5 mins).

Can ask Px to breath into paper bag – increased CO2 levels will cause vasodilation.

Question 19

What does the ophthalmologist do?

Answer 19

Ophthalmologist will aim to increase perfusion pressure:

By reducing IOP

By causing vasodilation

Question 20

How is IOP reduced?

Answer 20

• Intravenous acetazolamide
• Anterior chamber paracentesis (inserting needle into the anterior chamber and withdrawing 0.1 to 0.2 ml aqueous fluid.

Question 21

How is vasodilation of arteries caused?

Answer 21

Ocular massage

Fibrinolytic drugs may be used to break up the embolus, but most are cholesterol or calcium, which do not respond.

In arteritic CRAO due to giant cell arteritis high dose systemic steroids prescribed to prevent fellow eye/other vessels from being affected.

Question 22

Why is central retinal artery occlusion an emergency?

Answer 22

To save sight and life-risk of heart attack/stroke