A 63-year-old man presents with painless vision loss of the left eye that resolved within minutes

The image is consistent with a normal fundus, which along with the history indicates a diagnosis of monocular transient vision loss (TVL) 

• Two major causes of monocular TVL are:
  • Giant cell arteritis (GCA)
    
    • GCA causes ischemia through granulomatous inflammation of medium- to large-sized vessels (vasculitis).
    • It is classically associated with headache/scalp tenderness and elevated inflammatory markers.
    • It can cause transient as well as permanent vision loss.
  • Transient ischemic attack (TIA)
    • A TIA is a temporary disruption in blood supply without permanent neurological damage.
    • A TIA can cause ischemia that is painless, usually due to carotid stenosis or cardioembolism.

• Urgently perform the following work-up for causes of TVL in this patient.:
  • an eye examination
  • brain magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) (or computed tomography angiography [CTA])
  • complete blood cell (CBC) count, platelets, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), blood glucose, serum electrolytes, coagulation tests, renal function tests, lipid profile
  • electrocardiography (ECG), blood pressure
• Initiate an urgent neurovascular consult.
• Initiate an urgent ophthalmology consult for further evaluation.
• Consider all causes of vision loss and be broad about the differential diagnosis.

• Perform a full examination to look for clues of the underlying diagnosis, such as:
  • temporal artery tenderness or thready pulse (in GCA)
  • Hollenhorst plaques on the fundus examination (emboli formed from cholesterol deposition)
• Notably, many patients will have a normal fundus examination result.
• Perform fluorescein angiography to assess for areas of retinal nonperfusion and determine if there is delayed flow through the retina.

Example of a Hollenhorst plaque, highlighted on the right image in green.

Fluorescein angiography demonstrating a large temporal choroidal perfusion defect.

Treatment is aimed toward the underlying cause:

• GCA:
  • Perform urgent empiric steroid therapy until temporal artery biopsy and bloodwork confirm the diagnosis (clinical suspicion in light of negative artery biopsy may still warrant treatment with steroids to prevent vision loss).
• TIA:
  • Expedite a stroke work-up.
  • Consider anticoagulation or antiplatelet therapy if the TIA is due to an underlying cardiac etiology such as atrial fibrillation. 

• Interactive Case: Sudden Vision Loss
• Causes of monocular transient vision loss
• Video: Transient Monocular Blindness: Is Your Patient Having a Stroke?
• Careers in ophthalmology: neuro-ophthalmology