How do you differentiate and manage a patient with suspected retinal migraine versus migraine aura, considering their medical history and potential for permanent vision loss?

Differentiating Retinal Migraine from Migraine with Visual Aura

The critical distinction is monocularity: retinal migraine causes repeated monocular visual disturbances affecting one eye only (confirmed by covering the unaffected eye), while typical migraine with visual aura produces binocular visual phenomena affecting both visual fields simultaneously. 1

Key Diagnostic Features

Retinal Migraine

• Monocular visual symptoms only - the patient can confirm symptoms persist when covering the unaffected eye 1
• Repeated episodes of monocular visual loss, not just a single event 1
• Visual disturbances include partial or complete visual loss lasting less than 1 hour 2
• Symptoms spread gradually over ≥5 minutes (distinguishing from sudden TIA) 1
• Followed by headache within 60 minutes 1
• Most common in women of childbearing age with history of migraine with aura 2

Migraine with Visual Aura

• Binocular visual phenomena affecting both visual fields simultaneously 1
• Classic positive visual symptoms: scintillations, zigzag lines, fortification spectra 3
• Symptoms spread gradually over ≥5 minutes 3
• Individual aura symptoms last 5-60 minutes 3
• Two or more aura symptoms often occur in succession 3
• Headache accompanies or follows within 60 minutes 3

Critical Red Flags Requiring Urgent Evaluation

Prolonged aura >60 minutes requires urgent neuroimaging with MRI to exclude stroke, arteriovenous malformation, or structural lesions. 4

• Sudden, simultaneous onset of symptoms suggests TIA rather than migraine and requires urgent evaluation 4
• First episode of monocular visual symptoms requires urgent ophthalmologic consultation to exclude retinal artery occlusion, retinal detachment, or other ocular pathology 1
• Any persistent visual defect warrants immediate workup 2

Risk of Permanent Vision Loss

Nearly half of patients with recurrent transient monocular visual loss subsequently experience permanent monocular visual loss, making retinal migraine a vision-threatening condition. 2

• Although current diagnostic criteria require fully reversible visual loss, irreversible visual loss is part of the retinal migraine spectrum 2
• Persistent monocular scotomas have been documented in migraineurs, sometimes with retinal hemorrhagic lesions or cotton wool spots 5
• OCTA imaging has demonstrated acute monocular retinal oligemia during attacks, suggesting selective retinal ganglion cell layer involvement 6

Management Approach

For Retinal Migraine

Patients with monocular visual symptoms require urgent ophthalmologic consultation and aggressive migraine prophylaxis, not just symptomatic treatment. 1

• Standard migraine prophylaxis applies, but urgency is higher given vision loss risk 1
• Consider aspirin for potential antithrombotic effect in retinal vascular involvement 1
• Extensive investigation to exclude other causes: retinal vasculitis, embolic disease, thrombophilia, cardiac sources 5
• Serial ophthalmologic monitoring given risk of permanent visual loss 2

For Migraine with Visual Aura

• First-line acute treatment: NSAIDs (acetylsalicylic acid, ibuprofen, or diclofenac potassium) 3
• Second-line: triptans, combined with fast-acting NSAIDs if insufficient relief 3
• Prophylaxis: propranolol, amitriptyline, or topiramate 3
• Reassurance about benign nature when typical binocular pattern confirmed 3

Diagnostic Workup Algorithm

Step 1: Establish Monocularity vs Binocularity

• Have patient cover each eye individually during symptoms (if possible) or recall if symptoms affected one eye or both visual fields 1
• Monocular = retinal migraine pathway
• Binocular = migraine with aura pathway

Step 2: Assess Temporal Pattern

• Gradual onset over ≥5 minutes = migraine spectrum 3, 4
• Sudden, simultaneous onset = TIA/stroke, requires urgent evaluation 4
• Duration >60 minutes = requires urgent neuroimaging 4

Step 3: Confirm Recurrent Pattern

• At least 2 attacks required for formal migraine with aura diagnosis 4
• Repeated monocular episodes required for retinal migraine diagnosis 1
• Single episode requires broader differential including TIA, retinal artery occlusion 7

Step 4: Exclude Alternative Diagnoses

For monocular symptoms: retinal artery occlusion, retinal detachment, optic neuritis, giant cell arteritis (if age >50), retinal vasculitis 7, 5

For binocular symptoms: seizure (sudden onset, positive phenomena, brief duration <5 minutes), posterior reversible encephalopathy syndrome (PRES), visual snow syndrome (persistent, not episodic), stroke/TIA 7