Retinal Artery Occlusion- CRAO/BRAO Flashcards
What 2 types of Retinal Artery Occlusion are there?
CRAO
BRAO
What is CRAO?
Central Retinal Artery Occlusion
What is CRAO/BRAO caused by?
Embolus or thrombus blocking the artery
What is CRAO/BRAO commonly caused by?
Mostly Embolus- a glistening yellow cholesterol emboli can be may in retinal artery
Sometimes thrombus
What are the risk factors for CRAO/BRAO
HTN, High cholesterol, DM, giant cell arthritis, systemic lupus erythematosis tobacco use
What does CRAO/BRAO indicate?
Indicates increased risk of life-threatening cerebrovascular or cardiovascular incident.
What are the symptoms of CRAO/BRAO?
Sudden, severe, painless vision loss
Counting fingers to light perception
Field defect common in CRAO-peripheral more likely to recover
Why may they still have good VA despite having CRAO/BRAO?
If they have a cillio-retinal artery which 25% of people have and it supplies the macula
What are the early signs of CRAO/BRAO?
Cherry red spot at macula
Pale oedematous retina
Arterial attenuation
Emboli may be seen
RAPD
Segmentation
Why is there a cherry red spot?
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
What is segmentation?
Blood moves sluggishly in occluded vessels and blood flow may appear segmented (‘boxcarring’ or ‘cattle tracking’)
What are the late signs of CRAO/BRAO?
Optic disc atrophy
Arterial attenuation and segmentation
Can VA improve after chronic CRAO/BRAO?
VA usually remains markedly reduced despite treatment
What is amaurosis fugax?
It can happen after getting CRA/BRAO once the emboli has dislodged.It causes temporary visual loss
What are the symptoms of amaurosis fugax?
Sudden monocular loss of vision
Painless
“Like blind coming down”
Clears slowly in reverse direction
Repetitive
How do you manage amaurosis fugax?
Refer to G.P. urgently for CVD work up after excluding GCA
What is the visual outcome post CRAO/BRAO?
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.
How do you manage patient with CRAO/BRAO?
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.
What does the ophthalmologist do?
Ophthalmologist will aim to increase perfusion pressure:
By reducing IOP
By causing vasodilation
How is IOP reduced?
- Intravenous acetazolamide
- Anterior chamber paracentesis (inserting needle into the anterior chamber and withdrawing 0.1 to 0.2 ml aqueous fluid.
How is vasodilation of arteries caused?
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.
Why is central retinal artery occlusion an emergency?
To save sight and life-risk of heart attack/stroke
