What is the treatment for central retinal artery occlusion?

Treatment for Central Retinal Artery Occlusion

Patients with central retinal artery occlusion (CRAO) presenting within 4.5 hours of symptom onset should be immediately triaged to an emergency department and considered for intravenous tissue plasminogen activator (tPA) at 0.9 mg/kg after a thorough risk-benefit discussion, as this represents the only intervention with evidence of potential visual recovery (50% recovery rate when treated within this window). 1

Immediate Triage and Time-Critical Actions

• Treat CRAO as an ocular stroke emergency requiring immediate transfer to an emergency department or stroke center without any delay for outpatient evaluation 1, 2
• Communicate to emergency providers that the patient has experienced an "eye stroke" to ensure appropriate triage 2
• The therapeutic window is extremely narrow—ideally within 4.5 hours of symptom onset for meaningful intervention 1, 2
• Public awareness campaigns should emphasize sudden, painless, monocular visual loss as equivalent to unilateral weakness, facial droop, or speech difficulty 1

Emergency Department Evaluation Protocol

Parallel Workflow Assessment

Step 1: Immediate ophthalmological examination (or fundus photography via tele-ophthalmology) to confirm diagnosis and exclude giant cell arteritis (GCA) 1

Step 2: Simultaneous evaluation for thrombolysis candidacy 1:

• CT brain without contrast to exclude hemorrhage 1
• Establish time last known well 1
• Screen for contraindications to thrombolysis 1
• Calculate National Institutes of Health Stroke Scale 1
• Measure baseline visual acuity with correction and confrontation visual fields 1

Step 3: Rule out giant cell arteritis in all patients over 50 years of age 1, 2:

• Temporal artery palpation 1
• ESR and CRP if high clinical suspicion 1, 2
• If GCA is diagnosed or highly suspected, initiate immediate high-dose intravenous methylprednisolone (1g daily for 3 days) before any other intervention to prevent vision loss in the contralateral eye 2

Acute Treatment Options

Intravenous tPA (Primary Consideration)

For non-arteritic CRAO presenting within 4.5 hours 1:

• Administer alteplase 0.9 mg/kg (10% given over 1 minute, remainder over 59 minutes) 1
• Meta-analysis of observational studies demonstrates 50% rate of visual recovery (defined as final visual acuity of 20/100 or better when initial acuity was 20/200 or worse) when treated within 4.5 hours 1
• There is currently equipoise regarding IV tPA efficacy, as no fully powered randomized controlled trial has been completed 1
• The decision to use IV tPA requires thorough discussion with the patient acknowledging the limitations in current evidence 1
• Risk of symptomatic intracranial hemorrhage is low—no recorded cases when administered within 4.5 hours without concomitant anticoagulation 1

Intra-arterial tPA (Alternative for Select Cases)

Consider for patients presenting within 6 hours who are not candidates for IV thrombolysis and have access to an intra-arterial capable center 1:

• Requires mobilization of endovascular interventional team and catheterization laboratory 1
• Technique involves placement of small microcatheter (0.60 mm) in the ostium of the ophthalmic artery 1
• tPA delivered in 15 mg increments with serial bedside ophthalmological examinations until visual acuity restored, choroidal blush visualized, or 50 mg dose reached 1
• The only prospective randomized trial (EAGLE) was stopped prematurely for futility, but mean treatment time was 13 hours—treatment at early time points (<6 hours) remains untested 1
• Risks include arterial dissection, catheter-induced spasm, and dislodgement of atheromatous plaque with distal embolization 1

Conservative Treatments (Not Recommended)

Historical strategies including anterior chamber paracentesis, ocular massage, topical intraocular pressure-lowering agents, and sublingual isosorbide are not beneficial for visual outcomes 1

Secondary Prevention and Workup

Immediate Vascular Assessment

• Brain MRI with diffusion-weighted imaging shows concurrent silent brain infarctions in 19-25% of patients 2
• Vascular imaging reveals clinically significant carotid stenosis in up to 70% of patients 2
• High-grade stenosis of ipsilateral carotid artery requires urgent treatment as symptomatic carotid stenosis with either surgical revascularization or intensive medical management 1

Cardiac Evaluation

• Transthoracic echocardiography is reasonable to examine for cardioembolic source given high rate of structural heart disease 1
• Transesophageal echocardiography reserved for high suspicion of occult cardiac lesion with otherwise negative workup 1
• Ambulatory cardiac rhythm monitoring appropriate to screen for atrial fibrillation in patients without clear alternative cause 1
• If atrial fibrillation detected, initiate oral anticoagulation per established stroke secondary prevention guidelines 1

Antiplatelet Therapy

• Initiate antiplatelet therapy for secondary prevention 1
• Ticagrelor (either alone or in combination with aspirin) may be reasonable based on data from transient ischemic attack/minor stroke trials 1

Prognosis and Quality of Life Impact

• The natural history of CRAO is poor, with only 17% of patients achieving functional visual acuity in the affected eye 1
• Over 80% of patients present with visual acuity of "count fingers" or worse 2
• Unilateral uncorrectable visual loss significantly increases risk of falls (odds ratio 2.86) and functional dependence (odds ratio 7.50) 2
• May be disabling enough to warrant placement in long-term care facility with limitations in physical and social functioning 2

Stroke Risk

• Risk of stroke is highest within first 7 days after CRAO and remains elevated for 30 days 2
• Up to 24% of patients have concurrent cerebrovascular accident on diffusion-weighted MRI 2
• CRAO should be classified as stroke for purposes of determining CHADS2 and CHA2DS-VASc scores 1

Critical Pitfalls to Avoid

• Do not delay transfer to emergency department for outpatient evaluation or other treatments—time is critical 1, 2
• Do not miss giant cell arteritis in patients over 50—this requires immediate corticosteroids to prevent bilateral blindness 1, 2
• Do not rely on conservative treatments (ocular massage, anterior chamber paracentesis)—these have no proven benefit 1
• Do not assume mechanical thrombectomy is an option—the central retinal artery is only 160 µm in diameter at its terminus, making mechanical clot retrieval impossible with existing technology 1