Transient Monocular Visual Loss: When Is It an Emergency?

Background: Patients who experienced transient monocular vision loss (TMVL) commonly present to the emergency department for evaluation. Although multiple etiologies can cause TMVL, it is most important to identify patients with retinal ischemia and those with vasculitis (giant cell arteritis) as the cause of TMVL. Patients with transient retinal ischemia have the same risk of cardiovascular events and death as patients who experienced transient brain ischemia. Patients with giant cell arteritis are at imminent risk of visual loss.

Case Report: A 65-year-old man noticed three separate episodes of sudden onset of blurry vision in one eye. Ophthalmologic examination was normal but, as his symptoms were compatible with transient retinal ischemic attack, urgent investigations were initiated. He had normal inflammatory markers but computed tomography angiogram of the brain and neck demonstrated a large plaque in the ipsilateral internal carotid artery. Double anti-platelet therapy was started and stenting of the involved carotid artery was performed. The patient was symptom-free at the last follow-up. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Patients with retinal ischemia as the etiology of TMVL are at high risk of cardiovascular events and death. Their risk of cerebrovascular accidents is highest within 48 h from the episode of TMVL, thus they should have an urgent ophthalmologic examination and, if it is unrevealing, inflammatory markers should be checked and an urgent stroke prevention protocol should be initiated. Appropriate management with medical or surgical interventions significantly reduces morbidity and mortality in these patients.