Central Retinal Artery Occlusion
Summary
Central retinal artery occlusion (CRAO) is acute blockage of the central retinal artery, causing sudden, painless, profound monocular vision loss. It is the ocular equivalent of a stroke. The retina tolerates ischaemia for only 60-90 minutes before irreversible damage occurs. Classic fundoscopic finding is a "cherry-red spot" at the macula. CRAO is a marker for systemic vascular disease and requires urgent cardiovascular workup. Giant cell arteritis (GCA) must be excluded as it is a treatable cause.
Key Facts
- Presentation: Sudden painless monocular vision loss (usually profound)
- Fundoscopy: Pale retina with "cherry-red spot" at macula
- Time-critical: Retina tolerates ischaemia for 60-90 minutes only
- Aetiology: Embolic (carotid, cardiac) or arteritic (GCA)
- Action: Urgent ophthalmology + exclude GCA + stroke/TIA workup
Clinical Pearls
"Eye stroke" = treat like brain stroke — urgent vascular workup
Always ask about GCA symptoms (headache, jaw claudication, scalp tenderness, polymyalgia)
Cherry-red spot = pale ischaemic retina surrounding normal choroidal circulation at fovea
Why This Matters Clinically
CRAO causes catastrophic, usually permanent vision loss. Acute treatment options are limited but may help in very early presentation. More importantly, CRAO is a marker for high-risk cardiovascular disease — the patient is at high risk of stroke and MI.
Visual assets to be added:
- Fundus photo showing cherry-red spot
- Retinal artery anatomy
- CRAO vs BRAO comparison
- Cardiovascular workup algorithm
Incidence
- 1-2 per 100,000/year
- Increases with age
Demographics
- Mean age: 60-65 years
- Male predominance
- Associated with cardiovascular risk factors
Risk Factors
| Factor | Notes |
|---|---|
| Carotid artery disease | Embolic source |
| Atrial fibrillation | Cardiac embolism |
| Hypertension | |
| Diabetes | |
| Hyperlipidaemia | |
| Smoking | |
| Giant cell arteritis | Arteritic CRAO — treatable cause |
Mechanism
- Occlusion of central retinal artery (or branch)
- Retinal ischaemia
- Inner retinal layers affected (supplied by CRA)
- Outer retina (photoreceptors) supplied by choroid — initially preserved
Causes of Occlusion
| Cause | Notes |
|---|---|
| Embolic | Carotid plaque, cardiac source (AF, valve disease) |
| Thrombotic | Atherosclerotic stenosis |
| Arteritic (GCA) | Must exclude — treatable |
| Vasospasm | Rare |
| Hypercoagulable | Younger patients |
Cherry-Red Spot
- Central fovea appears red (normal choroidal circulation)
- Surrounded by pale, ischaemic retina
- Classic sign
Time Window
- Retina survives 60-90 minutes of complete ischaemia
- After this, irreversible damage occurs
Symptoms
Signs
GCA Symptoms (Must Ask)
Red Flags
| Finding | Significance |
|---|---|
| GCA symptoms | Treat immediately with high-dose steroids |
| Bilateral | GCA or embolic shower |
| Young patient | Consider hypercoagulable state |
Visual Acuity
- Severely reduced (counting fingers, hand movements, or light perception)
Pupil
- RAPD present
Fundoscopy
- Pale retina
- Cherry-red spot
- Attenuated arteries
- Box-carring
- May see embolus
Cardiovascular
- Blood pressure
- Carotid bruits
- Heart rhythm (AF)
Urgent — Exclude GCA
| Test | Notes |
|---|---|
| ESR | Elevated in GCA (often over 50) |
| CRP | Elevated |
| Platelet count | Often elevated in GCA |
If GCA suspected: Start high-dose steroids BEFORE temporal artery biopsy
Cardiovascular Workup
| Test | Purpose |
|---|---|
| ECG | Atrial fibrillation |
| Carotid Doppler | Stenosis, plaque |
| Echocardiogram | Cardiac source of embolism |
| Fasting lipids, glucose | Cardiovascular risk |
| Coagulation screen | If young or no risk factors |
Fluorescein Angiography
- Delayed or absent filling of retinal arteries
- Not always performed in acute setting
By Extent
| Type | Definition |
|---|---|
| CRAO | Central retinal artery occlusion — total |
| BRAO | Branch retinal artery occlusion — partial visual field loss |
By Aetiology
- Non-arteritic (embolic/thrombotic) — most common
- Arteritic (GCA) — ophthalmic emergency
Immediate — Within 90-120 Minutes (Limited Evidence)
| Intervention | Notes |
|---|---|
| Ocular massage | May dislodge embolus |
| Anterior chamber paracentesis | Reduces IOP, may improve perfusion |
| Carbogen inhalation | 95% O2 + 5% CO2; vasodilation |
| IV acetazolamide | Reduces IOP |
Reality: Most patients present too late for these to be effective. Evidence for acute treatment is limited.
Urgent — Exclude GCA
| Action | Details |
|---|---|
| Ask GCA symptoms | Headache, jaw claudication, scalp tenderness |
| Check ESR, CRP | |
| If GCA suspected | High-dose IV methylprednisolone 1g/day for 3 days |
| Then oral prednisolone | 60-80 mg/day; slow taper |
| Temporal artery biopsy | Within 2 weeks |
Cardiovascular Secondary Prevention
| Action | Details |
|---|---|
| Antiplatelet | Aspirin 75-300 mg |
| Statin | High-intensity |
| BP control | |
| Carotid intervention | If significant stenosis |
| Anticoagulation | If AF |
Referral
- Urgent ophthalmology
- Stroke/TIA pathway (same risk as stroke)
- Cardiology if cardiac source
Ocular
- Permanent vision loss (most cases)
- Rubeosis iridis (neovascularisation of iris) — weeks later
- Neovascular glaucoma
Systemic
- Stroke (high risk)
- MI
- Other thromboembolic events
Visual Prognosis
- Poor — most patients do not recover useful vision
- Better if cilioretinal artery present (spares macula)
- BRAO has better prognosis than CRAO
Systemic Prognosis
- 30% risk of stroke or cardiovascular event within 3 years
- Treat cardiovascular risk factors aggressively
Key Guidelines
- Royal College of Ophthalmologists Guidelines
- AAO Preferred Practice Pattern
Key Evidence
- Acute treatments have limited evidence
- Focus is on prevention of stroke and cardiovascular events
- GCA requires immediate high-dose steroids
What is CRAO?
CRAO is a blockage of the blood vessel that supplies your retina (the back of your eye). It causes sudden loss of vision in one eye.
Why Did This Happen?
- Usually caused by a blood clot or plaque from the heart or arteries
- Sometimes due to inflammation of blood vessels (GCA)
Will My Vision Come Back?
- Unfortunately, vision usually does not recover
- Treatment focuses on preventing problems in the other eye and preventing stroke
What Tests Will I Need?
- Blood tests
- Heart scan
- Neck artery scan
- Sometimes a biopsy of an artery near your temple
Resources
Key Reviews
- Hayreh SS. Central retinal artery occlusion. Prog Retin Eye Res. 2011;30(5):359-394. PMID: 21749659
- Biousse V, Newman NJ. Retinal and optic nerve ischemia. Continuum (Minneap Minn). 2019;25(5):1189-1210. PMID: 31584532
Guidelines
- AAO. Retinal and Ophthalmic Artery Occlusions Preferred Practice Pattern. 2019.