What are the immediate steps to take for painless sudden loss of vision in one eye?

Immediate Management of Painless Sudden Vision Loss

Send the patient immediately to a certified stroke center emergency department without delay—painless sudden monocular vision loss is a stroke equivalent requiring emergency evaluation within 24 hours, as vascular causes carry up to a 25% risk of concurrent silent brain infarction and highest stroke risk within the first 7 days. 1, 2, 3

Critical First Action: Immediate Referral

• Do not delay emergency department referral to obtain additional outpatient testing or imaging—the patient needs immediate triage to a stroke center with a note stating "Ocular TIA" or "Ocular Stroke." 2, 3
• The American Heart Association classifies transient monocular vision loss (TMVL/amaurosis fugax) and central retinal artery occlusion (CRAO) as stroke equivalents requiring the same emergency protocols as cerebral TIAs. 1, 3
• Stroke risk peaks within the first 7 days after symptom onset, making rapid diagnosis and treatment essential. 1, 2

What to Communicate to the Emergency Department

• Document whether vision loss was:
  • Transient (resolved within seconds to minutes)—this is retinal TIA 1
  • Persistent (ongoing)—this suggests CRAO or branch retinal artery occlusion (BRAO) 2, 3
• Note the patient's age—if over 50 years old, giant cell arteritis (GCA) must be ruled out urgently 3, 4
• Identify vascular risk factors: hypertension, diabetes, hyperlipidemia, smoking, atrial fibrillation 2, 4

Emergency Department Protocol (What Will Happen)

The stroke center will implement a 23-hour observation protocol including: 3

• Brain MRI with diffusion-weighted imaging—identifies concurrent silent brain infarctions present in 19-25% of patients 2, 3
• Vascular imaging (MRA or CTA of carotids)—significant carotid stenosis found in up to 70% of symptomatic patients 1, 3
• Cardiac monitoring and echocardiography—to identify embolic sources 3
• ESR and CRP if age >50 years—to screen for giant cell arteritis 3, 4

Time-Sensitive Treatment Considerations

• If presenting within 4.5 hours: Intravenous tissue plasminogen activator (tPA) at 0.9 mg/kg may be considered 2
• If GCA suspected: Immediate empiric high-dose corticosteroids must be started without waiting for temporal artery biopsy to prevent vision loss in the contralateral eye 2, 3
• Antiplatelet therapy should be initiated immediately upon vascular etiology confirmation 3

Key Clinical Clues for Specific Diagnoses

Giant Cell Arteritis (Age >50 years):

• Jaw claudication (most specific symptom, likelihood ratio 4.90) 1
• Scalp tenderness, proximal muscle pain, constitutional symptoms 4
• ESR >60 mm/h has high diagnostic value 1

Retinal Artery Occlusion:

• Painless vision loss in patients with vascular risk factors 4
• May have history of prior transient episodes 1

Acute Angle-Closure Glaucoma (painful, not painless):

• Ocular pain, headache, nausea—this is NOT painless and represents a different emergency 4

Critical Pitfalls to Avoid

• Never assume reperfusion eliminates stroke risk—even if vision returns, stroke risk remains elevated for 30 days 3
• Never delay referral for ophthalmology consultation first—send directly to stroke center ED 2, 3
• Never miss GCA in patients >50 years—empiric steroids should not be delayed for biopsy if clinical suspicion is high 3
• Never underestimate cardiovascular risk—new significant cardiovascular conditions are discovered in up to 70% of CRAO patients 3

Follow-Up After Emergency Evaluation

• Neurology follow-up within 2 weeks 3
• High-intensity statin for hyperlipidemia 3
• Blood pressure control 3
• Regular ophthalmology monitoring for neovascular complications 2