Sudden Visual Loss

Updated: May 18, 2016
  • Author: Gino A Farina, MD, FACEP, FAAEM; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
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Sudden visual loss is a common complaint with variable presentations among patients of different ages.

The differential diagnoses of sudden vision loss are vast. In general, monocular vision loss usually indicates an ocular problem. Binocular vision loss is usually cerebral in origin. Monocular vision loss may respect the horizontal midline. Binocular vision loss may respect the vertical midline.

Some patients describe their symptoms as a gradually descending gray-black curtain or as blurring, fogging, or dimming of vision. Symptoms usually last a few minutes but can persist for hours. Variation in frequency ranges from a single episode to many episodes per day; recurrences may continue for years but more frequently occur over seconds to hours.

Many different causes of sudden visual loss are recognized; however, the most common reason for painless sudden visual loss is ischemia. Vision loss with positive scotoma may be seen with migraine. Vision loss with a negative scotoma may be seen with amaurosis fugax.  Ischemia, often via mechanical obstruction, can affect any aspect of the visual system. Those who develop ischemia of the eye often have other evidence of atherosclerotic disease, such as coronary artery disease and peripheral vascular disease, which increases their susceptibility to ischemic events in other parts of the body. Risk factors include smoking, hypercholesterolemia, and hypertension.

Other etiologies of sudden visual loss include infection/inflammation, vasculitis, trauma, mechanical dysfunction, and idiopathic causes.



Ischemia compromises cell metabolism by reducing delivery of oxygen and other important nutrients to tissues. The resulting functional deficit may be temporary or permanent, depending on the degree of damage. Nomenclature of eye ischemia as given by Hedges and others includes the following [1] :

  • Transient visual obscuration (TVO) - Episodes lasting seconds that are associated with papilledema and increased intracranial pressure

  • Amaurosis fugax - Brief, fleeting attack of monocular partial or total blindness that lasts seconds to minutes

  • Transient monocular visual loss (TMVL) or transient monocular blindness (TMB) - A more persistent vision loss that lasts minutes or longer

  • Transient bilateral visual loss (TBVL) - Episodes affecting one or both eyes or both cerebral hemispheres and causing visual loss

  • Ocular infarction - Persistent ischemic damage to the eye, resulting in permanent vision loss




Sudden visual loss is uncommon.


Transient monocular visual loss (TMVL) in a person younger than 45 years may be benign; many attacks are probably vasospastic or due to migraine.

Transient bilateral visual loss (TBVL) is almost always associated with severe occlusive disease of the internal carotid artery (ICA), aortic arch, or bilateral occipital lobe ischemia.

Patients with ICA disease often have other systemic evidence of atherosclerosis, such as coronary and peripheral vascular disease. Other risk factors include smoking, hypercholesterolemia, and hypertension.


Whites, especially men, have a high incidence of ICA-origin atherosclerosis.

Blacks and Chinese and Japanese persons have a higher incidence of intracranial occlusive disease.


A strong male predominance (2:1) exists among patients with severe ICA disease.