What is the diagnostic approach for ocular stroke?

Diagnostic Approach for Ocular Stroke

The diagnosis of ocular stroke requires immediate ophthalmological examination followed by prompt referral to a stroke center for comprehensive evaluation, as it represents an ophthalmic emergency with significant risk for concurrent cerebrovascular events.

Initial Presentation and Examination

History Taking

• Duration of vision loss - critical for determining treatment window 1
• Symptoms of giant cell arteritis (headaches, scalp tenderness, jaw claudication, fever, myalgia) 1
• Medical history focusing on cardiovascular risk factors (hypertension, diabetes, hyperlipidemia) 1
• Ocular history (trauma, previous eye diseases, surgeries) 1
• Social history with emphasis on smoking 1

Clinical Examination

• Visual acuity assessment 1
• Pupillary function evaluation, including relative afferent pupillary defect 1
• Slit-lamp biomicroscopy of anterior segment 1
• Intraocular pressure measurement 1
• Dilated fundus examination - critical for identifying key findings 1:
  • Retinal whitening/edema
  • Retinal hemorrhages
  • Cotton wool spots
  • Retinal emboli
  • Retinal vascular "boxcarring"
  • Optic disc evaluation

Diagnostic Imaging and Testing

Essential Diagnostic Tests

• Color and red-free fundus photography - documents retinal findings and vascular caliber 1
• Optical Coherence Tomography (OCT) - reveals inner retinal hyper-reflectivity/edema in acute cases, even when fundus appears normal 1, 2
• Fluorescein angiography - demonstrates alterations in arterial flow patterns 1
• Indocyanine green angiography - particularly useful for visualizing choroidal circulation 1

Systemic Evaluation

• Brain imaging (CT/MRI) to evaluate for concurrent stroke 1
• Vascular imaging (carotid ultrasound, CTA, MRA) to identify carotid stenosis or occlusion 1, 3
• Cardiac evaluation (ECG, echocardiogram) to identify embolic sources 1
• Laboratory tests:
  • Complete blood count 1
  • Coagulation studies (PT/INR, aPTT) 1
  • Inflammatory markers (ESR, CRP) - particularly if giant cell arteritis is suspected 1

Diagnostic Algorithm

1. Initial ophthalmologic evaluation (within hours of symptom onset)

   • Complete eye examination with dilated fundoscopy 1
   • OCT to detect early retinal changes, especially in hyperacute cases 1, 2
   • Document findings with fundus photography 1

2. Immediate referral to emergency department/stroke center

   • Communicate diagnosis as "ocular stroke" or "eye stroke" 1
   • Do not delay for additional outpatient testing 1

3. Emergency department evaluation

   • Parallel ophthalmological and neurological assessment 1
   • Brain imaging to rule out cerebral infarction 1
   • Vascular imaging to identify carotid disease 1, 3
   • Laboratory tests to rule out arteritis and coagulopathies 1

4. Timing considerations

   • Most effective diagnosis and treatment occurs within 4.5 hours of symptom onset 1
   • OCT can detect changes even when fundus appears normal in hyperacute cases 2

Special Considerations

• Giant cell arteritis must be ruled out in all patients over 50 years with sudden vision loss 1
• Non-mydriatic fundus photography combined with OCT in emergency departments can facilitate rapid remote diagnosis 2
• Patients with ocular stroke have up to 25% risk of subsequent cerebral stroke 1
• Carotid artery stenosis/occlusion is a common finding that requires urgent evaluation 3

Common Pitfalls to Avoid

• Delaying referral to complete outpatient workup - immediate ED referral is essential 1
• Missing the diagnosis in hyperacute cases when fundus appears normal - OCT is crucial 2
• Focusing only on ocular treatment without addressing systemic vascular risk 1
• Failing to screen for giant cell arteritis in older patients 1
• Overlooking carotid artery disease as a potential cause 3