What is the workup and treatment for central retinal artery occlusion?

Central Retinal Artery Occlusion: Workup and Treatment

Patients with suspected central retinal artery occlusion (CRAO) should be immediately triaged to the nearest emergency department and treated as an acute ischemic stroke with intravenous tPA (Alteplase) if presenting within 4.5 hours of symptom onset. 1

Diagnosis and Initial Workup

Immediate Assessment

• Structured neurological assessment using National Institutes of Health Stroke Scale
• CT brain without contrast to rule out hemorrhage
• Ophthalmological examination to confirm CRAO diagnosis, including:
  • Assessment for relative afferent pupillary defect
  • Funduscopic examination looking for cherry-red spot in macula and pale retina
  • Visual acuity testing 1, 2

Screening for Etiology

• Screen for giant cell arteritis (GCA) in suspicious cases, as it accounts for 5% of CRAO cases 2, 1
• Carotid imaging to identify stenosis
• Transthoracic echocardiography to evaluate for cardioembolic sources
• Ambulatory cardiac rhythm monitoring for atrial fibrillation 1

Treatment Algorithm

For Patients Presenting Within 4.5 Hours

1. First-line treatment: Intravenous tPA (Alteplase)

   • Dosage: 0.9 mg/kg
   • Has demonstrated 50% rate of clinical recovery when administered within this timeframe 1
   • Safety profile similar to cerebral stroke treatment 3

2. For specialized centers with endovascular capabilities:

   • Consider intra-arterial thrombolysis via selective catheterization of the ophthalmic artery
   • Technique: placement of a small microcatheter (0.60 mm) in the ostium of the ophthalmic artery
   • tPA delivered in increments of 15 mg with serial bedside ophthalmological examinations
   • Continue until visual acuity is restored, choroidal blush visualized, or maximum dose of 50 mg reached 2

For All Patients (Regardless of Timing)

• Collaborative management between neurologist, ophthalmologist, and internist 1
• Aggressive control of vascular risk factors:
  • Hypertension
  • Diabetes
  • Hyperlipidemia 1

Important Caveats

Traditional Treatments to Avoid

The following treatments have not been proven effective and should not delay definitive care:

• Anterior chamber paracentesis
• Ocular massage
• Topical intraocular pressure-lowering agents
• Sublingual isosorbide dinitrate
• Hemodilution 2, 1

Emerging Treatments

• Hyperbaric oxygen therapy (HBOT) has shown some promise in case reports but is not yet endorsed in guidelines 4

Prognosis Considerations

• Natural history of untreated CRAO is poor, with only 17.7% achieving functional visual recovery 1
• Nearly 80% of untreated patients have "count fingers" vision or worse at follow-up 1
• CRAO patients have high risk of subsequent stroke and cardiovascular events, emphasizing the need for comprehensive vascular workup 1

Follow-up Care

• Ophthalmological follow-up to monitor for complications
• Continued management of vascular risk factors
• Secondary stroke prevention measures 1

Clinical Pearls

• CRAO should be considered an ocular emergency equivalent to cerebral stroke
• Time is critical - the 4.5-hour window for tPA treatment emphasizes the need for rapid diagnosis and intervention
• The differential diagnosis should include other causes of sudden, painless, monocular visual loss such as optic neuropathy, retinal detachment, and intraocular hemorrhage 2
• In cases of occlusion or high-grade stenosis of the internal carotid artery, tPA can be injected into the external carotid artery via collateral flow from the distal middle meningeal artery 2