What is the differential diagnosis (ddx) and management of sudden loss of vision?

Sudden Loss of Vision: Differential Diagnosis and Management

Sudden vision loss is a medical emergency requiring immediate ophthalmologic evaluation and urgent stroke workup, as retinal arterial ischemia represents an "eye stroke" with maximum stroke risk in the first 72 hours. 1, 2

Critical Initial Distinction: Vascular vs. Non-Vascular Etiology

High-Risk Vascular Causes (Require Emergency Stroke Evaluation)

Transient Monocular Vision Loss (TMVL/Amaurosis Fugax)

• Sudden, painless vision loss in one eye clearing within seconds to minutes 2
• Represents retinal TIA—a stroke equivalent per the American Heart Association 2
• Immediate action: Send directly to certified stroke center ED with note stating "Ocular TIA" or "Ocular Stroke" 1
• Call ahead to warn stroke team that "a stroke patient is on the way" 1

Central Retinal Artery Occlusion (CRAO)

• Painless, sudden, severe vision loss with cherry-red spot on fundoscopy 2
• Up to 25% have concurrent silent brain infarction on MRI 3, 4
• 70% have clinically significant carotid stenosis 3
• Requires same emergency stroke protocol as TMVL 1, 2

Branch Retinal Artery Occlusion (BRAO)

• Painless vision loss with sectoral visual field defect 4
• Even if reperfused, still requires urgent stroke evaluation within 24 hours 4
• Same high risk of concurrent cerebrovascular events 4

Non-Vascular Emergencies Requiring Urgent Ophthalmology

Giant Cell Arteritis (GCA)

• Consider in all patients >50 years with sudden vision loss 2, 5
• Key features: jaw claudication (LR 4.90), scalp tenderness, temporal artery abnormality 2, 5
• ESR >60 mm/h highly suggestive 2
• Start high-dose IV steroids immediately before temporal artery biopsy to prevent fellow eye involvement 3, 5

Acute Angle-Closure Glaucoma

• Painful red eye with headache, nausea, mid-dilated fixed pupil 5
• Immediate treatment: pilocarpine drops, IV/oral acetazolamide, IV mannitol 5

Retinal Detachment

• Curtain-like visual field defect, flashes, floaters 5
• Requires urgent surgical intervention 5

Optic Neuritis

• Pain with eye movements, color desaturation, relative afferent pupillary defect 5
• High-dose IV steroids and multiple sclerosis evaluation 5

Emergency Management Algorithm for Vascular Vision Loss

Within 72 Hours of Symptom Onset

Step 1: Ophthalmologic Confirmation 1

• Eye care provider serves as "gatekeeper" to confirm vascular etiology
• Do not perform extensive testing—refer immediately once diagnosis confirmed 1

Step 2: Immediate ED Referral to Stroke Center 1

• Hospitalize if presenting within 72 hours AND any of:
  • Abnormal brain DWI-MRI showing acute infarction 1
  • Large artery atherosclerosis on vascular imaging 1
  • Abnormal cardiac evaluation 1
  • Recurrent episodes (crescendo TIAs) 1
  • Inability to provide expedited outpatient follow-up 1

Step 3: 23-Hour Observation Protocol 1

• Brain MRI with diffusion-weighted imaging (identifies silent infarcts in 19-25% of patients) 3
• Vascular imaging (MRA or CTA) of carotids and cerebral vessels 1, 3
• Cardiac monitoring and echocardiography 1
• ESR and CRP if age >50 years 3
• Complete blood count with platelets 3

Step 4: Acute Treatment Considerations 3, 4

• If presenting within 4.5 hours: consider IV tPA (alteplase 0.9 mg/kg) 3, 4
• Hyperbaric oxygen therapy (100% O2 over 9 hours) may benefit some patients 3, 4

Step 5: Discharge with Secondary Prevention 1

• Antiplatelet therapy (start immediately if no contraindication) 1, 3
• High-intensity statin for hyperlipidemia 1
• Blood pressure control 1
• Neurology follow-up within 2 weeks 1

Beyond 72 Hours of Symptom Onset

Patients seen days after visual loss still require urgent stroke workup 1

• Start antiplatelet agent without delay 1
• Arrange urgent outpatient neurology consultation with stroke expertise 1
• Complete vascular and cardiac evaluation as outpatient 1

Imaging Approach by Clinical Scenario

Per ACR Appropriateness Criteria 1

• Visual pathway lesions can occur anywhere from globe to primary visual cortex 1
• MRI preferred for optic nerve, chiasm, and posterior visual pathway evaluation 1
• CT useful for acute presentations when MRI unavailable 1
• Contrast indicated when masses or inflammatory processes suspected 1

Critical Pitfalls to Avoid

Do not delay referral for additional testing 1

• Eye care providers should immediately refer confirmed vascular cases without attempting further workup themselves 1

Do not assume reperfusion eliminates stroke risk 4

• Even if vision returns, stroke risk remains highest in first 7 days 3, 4
• Only 33% of ophthalmologists currently follow guideline recommendations for ED transfer 4

Do not miss GCA in elderly patients 2, 5

• Always check ESR/CRP in patients >50 years with sudden vision loss 2, 3
• Empiric steroids should not be delayed for biopsy 3, 5

Do not underestimate cardiovascular risk 3

• New significant cardiovascular condition discovered in up to 70% of CRAO patients 3
• Risk of stroke and acute coronary syndrome remains elevated for 30 days 3, 4