Transient Monocular Vision Loss

    • Abrupt loss of vision in one eye lasting from seconds to hours
    • Produced by diminished blood flow to the eye
    • Common causes
      • Systemic hypotension
      • Reduced cardiac output
      • Cervical carotid stenosis
        leading to reduced ocular perfusion or embolism
      • Atrial fibrillation
      • Cardiac valve or mural thrombus
      • Retinal vein occlusion
      • Presumed vasospasm of retinal arterioles (misnamed as “retinal migraine”)
      • Hyperviscosity/hypercoagulable states
      • Optic disc edema (including papilledema)
      • Demyelinating optic neuropathy
    • Blank, fuzzy, dark, bright, or flickering area in the visual field of one eye
    • Trap: patients with transient binocular (homonymous) visual loss often report that the deficit affected only one eye—the eye with the temporal hemianopia!
    • Visual loss provoked by sitting or standing = reduced cardiac output, systemic hypotension, optic disc edema (especially papilledema)
    • Visual loss provoked by exercise or heat = demyelinating optic neuropathy
    • Mucus debris in the tear film (usually clears with blinking)
    • Corneal edema from endothelial malfunction (usually worse on awakening)
    • Elicit features suggesting that transient vision loss was monocular
      • Vision was undisturbed when the patient closed the affected eye
      • Visual loss primarily involved the nasal visual field
      • Vision loss did not include expanding zigzags, waves, silver, broken glass, or heat waves
    • Perform ophthalmoscopy to look for
      • Papilledema
      • Retinal embolus
      • Venous stasis retinopathy
    • Perform formal visual field examination (to detect a lingering deficit)
    • Measure blood pressure (looking for systemic hypertension or hypotension)
    • Check erythrocyte sedimentation and C-reactive protein promptly (looking for giant cell arteritis)
    • Send the patient for prompt investigation of the underlying cause; the more recent the symptom, the quicker the referral; consider using an emergency room if symptoms happened less than a week earlier because most strokes occur within weeks of a first transient ischemic attack
    • Ophthalmic examination is usually normal
    • Very high or low systemic blood pressure must be corrected
    • Elevated erythrocyte sedimentation rate and C-reactive protein prompt consideration of giant cell arteritis
    • Elevated blood count and protein electrophoresis may indicate hypercoagulable state
    • Cervical carotid ultrasound or CT and CTA may indicate stenosis or dissection
      • Bifurcational stenosis of 50% of more
        often prompts endarterectomy/stenting, although the evidence is not robust that it reduces eye or brain stroke in isolated transient monocular vision loss
      • Trap: bifurcational stenosis of less than 50% does not justify endarterectomy/stenting
    • Echocardiogram rarely discloses cardiogenic cause (irregular heart wall motion or valvular disease)
    • Brain MRI may disclose remote or recent ischemic stroke
    • Heart rhythm monitoring may disclose atrial fibrillation or other rhythm disturbance
    • If no explanation is found in older adults, conventional stroke risk reduction measures are recommended
    • If no explanation is found in young adults, retinal vasospasm may be considered the presumptive cause and treated with calcium channel blockers, but only if the attacks are frequent

    Transient Vision Loss

    Transient Monocular Vision Loss Transient Binocular Vision Loss