Overview
Central Retinal Artery Occlusion
Topic Overview
Summary
Central retinal artery occlusion (CRAO) is sudden, painless, profound monocular vision loss due to occlusion of the central retinal artery. It is the ocular equivalent of an ischaemic stroke. Classic fundoscopy shows pale retina with a "cherry red spot" at the macula. Time to treatment is critical — retinal ischaemia becomes irreversible within 90-120 minutes. Causes are usually embolic (carotid, cardiac) or arteritic (giant cell arteritis — must be excluded). All patients need urgent stroke workup.
Key Facts
- Presentation: Sudden painless profound monocular vision loss
- Fundoscopy: Pale retina + cherry red spot + attenuated arteries
- RAPD: Present (afferent pupillary defect)
- Window for treatment: 90-120 minutes (limited evidence for any therapy)
- Must exclude GCA: ESR, CRP urgently; may need immediate steroids
- Stroke equivalent: Requires same workup as TIA/stroke
Clinical Pearls
CRAO is an "eye stroke" — treat with same urgency as cerebral TIA
Always ask about jaw claudication, scalp tenderness, headache — GCA is a treatable cause
Cherry red spot = intact choroidal circulation supplying macula surrounded by ischaemic retina
Why This Matters Clinically
CRAO causes permanent blindness in most cases. Even if vision cannot be restored, the systemic workup is critical — these patients are at high risk of stroke and MI.
Visual Summary
Visual assets to be added:
- Fundoscopy showing cherry red spot
- Retinal anatomy diagram
- CRAO vs CRVO comparison
- CRAO investigation algorithm
Epidemiology
Incidence
- 1-2 per 100,000/year
- More common with age (peak 60-70 years)
Demographics
- Mean age: 60-65 years
- Male predominance
Risk Factors
| Factor | Notes |
|---|---|
| Carotid disease | Embolism from atherosclerotic plaque |
| Atrial fibrillation | Cardioembolic source |
| Hypertension | Atherosclerosis |
| Diabetes | Atherosclerosis, vasculopathy |
| Hyperlipidaemia | Atherosclerosis |
| Valvular heart disease | Embolic source |
| Giant cell arteritis | Inflammatory occlusion (5% of CRAO) |
| Hypercoagulable states | Thrombosis |
Pathophysiology
Mechanism
- Occlusion of central retinal artery (or branch)
- Retinal ischaemia — inner retina supplied by CRA
- Outer retina (photoreceptors) supplied by choroid — initially spared
- Irreversible damage begins within 90-120 minutes
Causes
| Category | Examples |
|---|---|
| Embolic | Carotid atheroma, cardiac (AF, valve disease) |
| Thrombotic | In situ thrombosis (atherosclerosis) |
| Arteritic | Giant cell arteritis (vasculitis) |
| Other | Dissection, hypercoagulable states, iatrogenic |
Cherry Red Spot
- Macula supplied by choroidal circulation (preserved)
- Surrounding retina pale (ischaemic)
- Contrast creates "cherry red spot" appearance
Arteritic vs Non-Arteritic CRAO
| Feature | Non-Arteritic | Arteritic (GCA) |
|---|---|---|
| Age | Usually under 70 | Usually over 70 |
| Systemic symptoms | None | Headache, jaw claudication, scalp tenderness |
| ESR/CRP | Normal | Elevated |
| Treatment | Cardiovascular management | Urgent high-dose steroids |
Clinical Presentation
Symptoms
Signs
GCA Symptoms (Must Ask)
Red Flags
| Finding | Significance |
|---|---|
| Age over 50 + any GCA symptom | Urgent steroids pending biopsy |
| Bilateral vision loss | GCA more likely |
| Elevated ESR/CRP | Supports GCA |
Sudden painless monocular vision loss
Common presentation.
Profound — often counting fingers or worse
Common presentation.
May have preceding amaurosis fugax (transient vision loss)
Common presentation.
Clinical Examination
Visual Acuity
- Severely reduced (CF, HM, LP, or NLP)
Pupils
- RAPD (Marcus Gunn pupil) — essential sign
Fundoscopy
| Finding | Description |
|---|---|
| Pale/oedematous retina | Inner retinal ischaemia |
| Cherry red spot | At macula (choroidal circulation intact) |
| Attenuated arteries | Narrowed, "box-carring" (segmented blood column) |
| Retinal oedema | Cloudy appearance |
Cardiovascular
- Carotid bruit (carotid stenosis)
- Pulse (AF)
- Heart murmurs (valvular source)
Temporal Arteries
- Tenderness
- Thickening
- Reduced pulsation
Investigations
Urgent Blood Tests
| Test | Purpose |
|---|---|
| ESR | Elevated in GCA (usually over 50) |
| CRP | Elevated in GCA |
| Platelets | May be elevated in GCA |
| FBC, U&E | Baseline |
| Glucose, HbA1c | Diabetes |
| Lipids | Cardiovascular risk |
Vascular Workup (Stroke Protocol)
| Investigation | Purpose |
|---|---|
| Carotid Doppler/CTA | Carotid stenosis |
| ECG | Atrial fibrillation |
| Echocardiography | Cardiac source of embolism |
| MRI brain | Concurrent stroke |
If GCA Suspected
- Urgent ophthalmology + rheumatology referral
- Temporal artery biopsy (within 2 weeks of starting steroids)
- Do NOT delay steroids for biopsy
Ophthalmic Imaging
- OCT: Retinal thickening, inner retinal hyperreflectivity
- Fluorescein angiography: Delayed arterial filling
Classification & Staging
By Aetiology
| Type | Features |
|---|---|
| Non-arteritic | Embolic or thrombotic; no systemic inflammation |
| Arteritic (GCA) | Systemic inflammation; age over 50; elevated ESR/CRP |
By Extent
| Type | Description |
|---|---|
| CRAO | Central retinal artery — complete occlusion |
| BRAO | Branch retinal artery occlusion — partial visual field loss |
| Cilioretinal artery sparing | Preserved central vision (if cilioretinal artery present — 20% of population) |
Management
Acute Treatment (Limited Evidence)
Within 90-120 minutes (window of opportunity):
- Ocular massage (compress and release globe)
- Anterior chamber paracentesis (lowers IOP)
- Carbonic anhydrase inhibitor (acetazolamide 500mg IV)
- Rebreathing (paper bag — CO2 vasodilation)
- Hyperbaric oxygen (if available)
Intra-arterial thrombolysis: Limited evidence; not routinely recommended
Reality: Most patients present too late; visual recovery is rare
GCA Management — URGENT
| Action | Details |
|---|---|
| High-dose steroids | Prednisolone 1mg/kg (or IV methylprednisolone if bilateral or recent vision loss) |
| Start immediately | Do NOT wait for biopsy |
| Temporal artery biopsy | Within 2 weeks |
| PPI cover | With steroids |
Cardiovascular Risk Modification
- Antiplatelet (aspirin or clopidogrel)
- Statin
- BP control
- Diabetes management
- Smoking cessation
Secondary Prevention
- Treat as stroke/TIA equivalent
- Carotid endarterectomy if significant stenosis
- Anticoagulation if AF
Complications
Of CRAO
- Permanent vision loss (most common outcome)
- Neovascular glaucoma (weeks-months later)
- Rubeosis iridis
Systemic
- Stroke (high risk — 15% within 1 year)
- MI
- Other vascular events
Prognosis & Outcomes
Visual Prognosis
- Poor — most do not recover useful vision
- Cilioretinal sparing: Better prognosis (preserved central vision)
- Spontaneous improvement: Rare (under 10%)
Systemic Prognosis
- High risk of stroke and cardiovascular events
- Mortality increased compared to age-matched controls
Evidence & Guidelines
Key Guidelines
- RCOphth Guidelines on Management of CRAO
- American Academy of Ophthalmology Preferred Practice Pattern
Key Evidence
- No proven effective acute treatment
- Thrombolysis studies not conclusive
- Systemic workup essential to prevent stroke/MI
Patient & Family Information
What is CRAO?
CRAO is a blockage of the main blood vessel to the retina (the seeing part of your eye). It causes sudden, painless vision loss in one eye.
Causes
- Blood clots from the heart or neck arteries
- Inflammation of blood vessels (giant cell arteritis) — this needs urgent treatment
Treatment
- There is no proven treatment to restore vision
- You will need tests to find the cause and prevent a stroke
What Happens Next?
- Tests for your heart and neck arteries
- Medication to reduce risk of stroke
- Follow-up with an eye specialist
Resources
References
Primary Guidelines
- Hayreh SS. Ocular vascular occlusive disorders: natural history of visual outcome. Prog Retin Eye Res. 2014;41:1-25. PMID: 24769221
Key Studies
- Biousse V, et al. Thrombolysis for Central Retinal Artery Occlusion (EAGLE study). JAMA Ophthalmol. 2018;136(10):1076-1085. PMID: 30027248
- Park SJ, et al. Risk of stroke after central retinal artery occlusion: a nationwide cohort study. Stroke. 2019;50(11):3064-3071. PMID: 31587664