What are the implications and necessary actions for temporary painless one-sided vision loss?

Temporary Painless One-Sided Vision Loss

Temporary painless one-sided vision loss (transient monocular vision loss, TMVL) is a retinal transient ischemic attack requiring immediate emergency department referral to a certified stroke center—this is a stroke equivalent with maximum risk of cerebral stroke within the first 48-72 hours. 1, 2

Immediate Recognition and Action

Send the patient directly to the nearest emergency department affiliated with a certified stroke center immediately, with a note stating "Ocular TIA" or "Ocular Stroke," and call ahead to warn them "a stroke patient is on the way." 1, 3

• Do not perform additional testing yourself before referral—eye care providers should confirm the vascular diagnosis and immediately refer without attempting further workup 1, 3
• The stroke risk is highest within the first 7 days, with peak risk in the first 48 hours, making every minute count 2, 3, 4
• Even if vision has completely recovered, the cardiovascular risk remains identical to cerebral TIA patients 1, 2

Critical Differential: Giant Cell Arteritis

Before sending to the stroke center, consider giant cell arteritis (GCA) in any patient over 50 years old 1, 3:

• Ask specifically about jaw claudication (most specific symptom, likelihood ratio 4.90), headache, scalp tenderness, and constitutional symptoms 2
• If GCA is suspected, check ESR and CRP immediately—do not delay empiric steroids for temporal artery biopsy if clinical suspicion is high 3
• GCA represents imminent risk of permanent bilateral blindness and requires different emergency management than embolic TMVL 1, 4

What Happens at the Stroke Center

The American Heart Association and American Academy of Ophthalmology recommend a standardized 23-hour observation protocol 3:

• Brain MRI with diffusion-weighted imaging to detect silent cerebral infarcts (present in up to 25% of retinal ischemia cases) 2, 3
• Vascular imaging (MRA or CTA) of carotids and cerebral vessels—significant carotid stenosis is found in up to 70% of symptomatic retinal vascular events 2, 3
• Cardiac monitoring and echocardiography to identify cardioembolic sources 3
• Immediate antiplatelet therapy (typically aspirin or dual antiplatelet therapy depending on findings) 1, 3, 4
• High-intensity statin for hyperlipidemia and blood pressure control 1, 3

Hospitalization Criteria

Patients require admission to a stroke unit if presenting within 72 hours AND any of the following 3:

• Abnormal brain DWI-MRI showing acute infarction
• Large artery atherosclerosis requiring intervention
• Abnormal cardiac evaluation suggesting cardioembolic source
• Recurrent episodes of TMVL
• Inability to provide expedited outpatient follow-up

Patients Presenting Days After the Episode

Even patients seen several days after symptom resolution need urgent stroke workup 1:

• Start antiplatelet therapy immediately without delay 1
• Arrange urgent outpatient neurology consultation with stroke expertise (within 2 weeks maximum) 1, 3
• These patients still require the same diagnostic workup, just potentially as outpatients rather than in the ED 1

Critical Pitfalls to Avoid

• Never assume reperfusion eliminates stroke risk—the cardiovascular risk remains elevated for 30 days, with new significant cardiovascular conditions discovered in up to 70% of patients 3
• Never delay referral to obtain imaging yourself—the stroke center will coordinate all appropriate testing 1, 3
• Never underestimate the seriousness—the American Heart Association defines retinal cell death from ischemia as a stroke equivalent, not a benign warning sign 2
• Never miss GCA in older patients—check ESR/CRP in all patients over 50 years with sudden vision loss 2, 3

Why This Matters for Morbidity and Mortality

The risk of subsequent cerebral stroke after TMVL may be slightly lower than after cerebral TIA, but the overall risk for cardiovascular events and death remains identical 2. Appropriate emergency management with medical or surgical interventions (such as carotid endarterectomy or stenting for significant stenosis) significantly reduces morbidity and mortality 4. The window for intervention is narrow—prompt diagnosis and treatment within the first few days is mandatory to prevent devastating outcomes 1, 2.