Retinal Artery Occlusion

Question 1

Types of Retinal Artery Occlusion?

Answer 1

o Branch Retinal Artery Occlusion (BRAO)
o Central Retinal Artery Occlusion (CRAO)
o Cilioretinal Artery Occlusion

Question 2

Causes/risk factors of Retinal Artery Occlusion?

Answer 2

• Atherosclerosis (similar to RVO) – diabetes, high cholesterol, high BP, age
• Carotid embolism – if have cholesterol/calcium/fibrin plaque sitting within carotid, tiny bit of this plaque can break away, travels along carotid artery – embolus can lodge in one of retinal artery
• Giant Cell Arteritis
• Haematological conditions

Question 3

Symptoms of Central Retinal Artery Occlusion?

Answer 3

Sudden painless loss of vision
V. v. bad vision - <6/60 (or may just have light perception)
Afferent pupil defect
Field loss
Scotoma/shadow
Asymptomatic - less common in RAO than in RVO

Question 4

Signs of Central Retinal Artery Occlusion?

Answer 4

• Reduced vision
• RAPD – definitely if have CRAO, may not be in BRAO
• Retinal pallor in distribution of blockage – CRAO entire retina is pale apart from macula
• “Cherry red spot” (CRAO) – at macula, fovea v thin and see glow from below (choroid w/ BVs)
• In 1st 48hrs, inner retina is swollen & oedematous (retinal nerve cell oedema) –> cherry red spot at fovea
• In BRAO, will see pallor just along branch where there is the blockage and no where else
• Thinning of retinal arteries
• Visual field loss
• Later retina appears normal, apart from optic atrophy

Question 5

Management of Central Retinal Artery Occlusion?

Answer 5

• Breathing into a paper bag
• IOP lowering:
  o Digital massage – massage eye using thumb – can sometimes get embolism to move
  o Diamox (used in glaucoma to reduce pressure) or paracentesis (releasing pressure from eye surgically)
  o All of these need to be done within hours of blockage happening for it to show any real benefit
• Stroke clinic referral – high risk of blockage in brain or heart after having one in eye
• A CRAO is a stroke
  o Next embolus may cause paralysis or loss of speech
• No ophthalmic management likely to improve vision
  o REFER immediately to stroke unit (EMERGENCY) –> blue-light to hospital –> same day referral if happened within previous 24hrs
  –> if occurred over 24 hrs ago hard to save vision but still URGENT referral
  Referral is not to save the px’s eye - it is to save the other eye and the px’s life

Question 6

Branch Retinal Artery Occlusion Symptoms?

Answer 6

None, macular not involved, would probably go unnoticed

Question 7

Branch Retinal Artery Occlusion Signs?

Answer 7

VF inferior defect if blockage in superior arcade (& vice versa)