Transient monocular vision loss commonly brings patients to the ED. TMVL has many causes, and it is critical to identify patients with retinal ischemia and those with giant cell arteritis as its cause. (J Emerg Med. 2021;60:192.)
Patients with transient retinal ischemia have the same risk of cardiovascular events and death as patients who experience transient cerebral ischemia. The risk of stroke is highest within the first few days after retinal TIA, so urgent investigation is crucial. (J Emerg Med. 2021;60:192; Ophthalmology. 2018;125:1597; https://bit.ly/2OXQ0L7.)
Patients with giant cell arteritis are at imminent risk of vision loss. (J Emerg Med. 2021;60:192; Clin Ophthalmol. 2016;10:297; https://bit.ly/391ZJH3.)
Patients with ischemic TMVL due to retinal TIA commonly report painless blurred vision, often described as seeing a veil, shade, or haze that ascends or descends vertically. (J Emerg Med. 2021;60:192; Ophthalmology. 2018;125:1597; https://bit.ly/2OXQ0L7.) The episodes usually last 30 seconds to several minutes and resolve on their own. A key characteristic distinguishing retinal TIA from other causes of TMVL is the presence of graying, darkening, blacking out, or clouding of vision (negative visual phenomena) from impaired neural activity in the ischemic retina. (J Emerg Med. 2021;60:192; Ophthalmology. 2018;125:1597; https://bit.ly/2OXQ0L7.)
In contrast, visual perceptions, such as photopsia and scintillations described as seeing colors, pulsating zigzagging lines, sparkles, flashing lights, or heat waves (positive visual phenomena), are most commonly associated with migraines and not ischemia. Ischemic TMVL is transient and does not produce abnormalities on ophthalmoscopy, as opposed to central retinal artery occlusion.
It is also important to consider GCA in any patient over age 50 with transient or permanent monocular vision loss. Transient vision loss can be a warning sign of impending luminal occlusion of the involved vessels and permanent optic nerve and retinal ischemia in patients with GCA. All patients over 50 with transient visual loss should have inflammatory markers checked (CRP and ESR); the risk of GCA is very low if both are normal. (J Emerg Med. 2021;60:192.)
Patients who have a high probability of giant cell arteritis (those with elevated inflammatory markers and patients with systemic symptoms, such as new onset of headaches, jaw claudication, skull tenderness, and constitutional symptoms) should be started immediately on a high dose of glucocorticoids and referred for temporal artery biopsy.
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