What is a retina Transient Ischaemic Attack (TIA) in an older adult with a history of vascular disease, such as hypertension, diabetes, or hypercoagulable states?

What is a Retinal TIA?

A retinal TIA (transient ischemic attack), also called transient monocular vision loss (TMVL) of vascular origin, is a brief episode of retinal ischemia causing sudden, painless, monocular vision loss that resolves completely, typically within minutes to one hour, without permanent retinal infarction—it is the ocular equivalent of a cerebral TIA and represents a medical emergency with the same stroke risk as brain TIA. 1

Clinical Definition and Pathophysiology

• Retinal TIA manifests as acute, transient, painless monocular vision loss caused by temporary occlusion of the central retinal artery or a branch retinal artery, reflecting acutely impaired blood flow in the anterior cerebral and ocular circulation. 1

• The American Heart Association formally recognizes retinal ischemia as a stroke equivalent, defining central nervous system infarction as "brain, spinal cord, or retinal cell death attributable to ischemia." 1

• The mechanisms and causes are identical to acute cerebral infarctions in the territory of the internal carotid artery—primarily thromboembolic disease in 95% of cases. 1

• Unlike permanent retinal artery occlusions (BRAO/CRAO which are retinal strokes), retinal TIA resolves without evidence of permanent retinal infarction, though symptoms typically last less than one hour, most often just minutes. 2

Critical Stroke Risk

The stroke risk following retinal TIA is substantial and peaks within the first few days:

• Stroke risk is 1.36% at 2 days, 2.06% at 7 days, 2.78% at 30 days, and 3.42% at 90 days after retinal TIA when patients receive urgent specialized stroke care. 1

• Without urgent treatment, stroke risk reaches 3.6% at 2 days and 11% at 7 days, emphasizing the critical importance of immediate evaluation. 1

• Up to 31% of patients with retinal TIA have silent cerebral infarctions on diffusion-weighted MRI (DWI-MRI), indicating concurrent brain ischemia even without neurological symptoms. 1

• Patients with retinal TIA have not only high stroke risk but also major risk of acute coronary events, with acute coronary syndrome occurring in 5.4% at one year. 1

Why This is a Medical Emergency

Retinal TIA must be managed as urgently as cerebral TIA because:

• The risk of subsequent disabling stroke is maximum within the first few days after visual loss, making prompt diagnosis and triage mandatory. 1

• Studies demonstrate that immediate evaluation and treatment in specialized stroke centers significantly reduces stroke recurrence, with the EXPRESS and SOS-TIA studies revolutionizing TIA management by showing better outcomes with urgent care. 1

• Between 11.8% to 30.8% of retinal TIA patients have acute cerebral infarctions on DWI-MRI, often multiple and in various vascular territories, indicating active embolic disease. 1

Clinical Presentation

Key features that distinguish retinal TIA:

• Sudden, painless, monocular vision loss that is the hallmark presentation—patients describe a "curtain" or "shade" coming down over one eye. 1

• Vision loss is transient and resolves completely, typically within minutes to one hour, leaving no permanent visual deficit. 2

• Funduscopic examination may be normal during or after the episode, unlike CRAO/BRAO where retinal whitening and other findings persist. 1

• A relative afferent pupillary defect may be present during the acute episode but resolves with vision recovery. 1

Associated Risk Factors

Retinal TIA occurs in patients with vascular risk factors identical to cerebral stroke:

• Hypertension (57-77%), diabetes (14-61%), hyperlipidemia (23-74%), and atrial fibrillation (6-20%) are highly prevalent in retinal TIA patients. 1

• Ipsilateral carotid artery stenosis ≥70% is found in up to 40% of patients with retinal TIA, making vascular imaging essential. 1

• Age is a key risk factor, with incidence increasing significantly after age 60-65 years. 1

• Smoking, obesity, and ischemic heart disease are additional modifiable risk factors. 1

Immediate Management Required

Eye care professionals must recognize that retinal TIA requires immediate stroke center referral:

• Patients should be triaged to the nearest emergency department immediately without attempting further testing in the ophthalmology office. 1

• Urgent brain MRI with diffusion-weighted imaging, vascular imaging (carotid ultrasound or CTA/MRA), and cardiac assessment must be performed within 24-48 hours to identify stroke risk and guide prevention. 1

• The diagnostic workup should mirror that of cerebral TIA, including evaluation for carotid stenosis, cardiac sources of emboli (especially atrial fibrillation), and other stroke mechanisms. 1, 3

Critical Pitfall to Avoid

The most dangerous error is dismissing retinal TIA as "just an eye problem":

• Many health professionals incorrectly consider retinal ischemia relatively benign compared to cerebral ischemia, leading to delayed and incomplete evaluations that result in preventable strokes. 1

• Delayed access to stroke care results in delayed antiplatelet therapy, delayed carotid intervention when indicated, and significantly higher stroke rates—one study showed 18.8% stroke risk at 90 days with delayed care. 1

• Public and provider education emphasizing painless monocular vision loss as a stroke symptom is essential for improving outcomes. 1