The vision in this condition may be reduced to being completely unable to see light out of the affected eye. Usually this is painless, and the loss of vision is severe. However, if the clot is large it may not dislodge, and the vision remains blacked-out. In some cases, the clot will rapidly dislodge, and the vision will return (Amaurosis fugax, discussed above).
If a clot (embolus) breaks free from the wall of a blood vessel leading up the neck or to the eye, it can lodge in the retinal arteries causing an obstruction of blood flow to the eye, and a loss of vision. Retinal Artery Occlusion (Central Retinal Artery Occlusion and Branch Retinal Artery Occlusion)
This spasm can lead to a temporary black-out of vision on one side, and is fairly rare. Retinal migraine is a spasm of the artery leading into the eye which supplies the retina.Sometimes even eye movements are enough to induce a temporary loss of vision. Increased intracranial pressure (the pressure of the fluid around the brain) can cause momentary lapses of vision especially when moving, such as standing from a sitting position.People which this problem may notice temporary dimming of vision affecting both eyes, and possibly imbalance. Obstruction of the vertebral arteries, which course up the back of the neck and supply the visual part of the brain.Other problems which cause a temporary loss of vision include: Vascular evaluation and possibly anti-coagulation (use of blood thinners) is indicated for this problem. This problem falls into the same category as "transient ischemic attacks" (or TIA's), which may herald a stroke. The embolus may be a cholesterol crystal, a calcium deposit, or a true blood clot. The source of the clot (or embolus) is usually from the carotid arteries leading up the neck to the brain, or from the heart. When the clot breaks up, the blood flow returns, as does the vision. The clot obstructs the blood flow to the retina, and the vision blacks-out. Most commonly, this happens in older people with arteriosclerosis and possibly vascular disease, and is due to small clots breaking off of the walls of arteries and then lodging in the vessels of the eye. The problem can recur in the future, and could affect either eye. The black-out may last minutes, and then the vision returns. This is usually affects one eye, is painless, and is often described like a "shade coming down over the vision" of that eye. Amaurosis FugaxĪmaurosis fugax refers to a temporary black-out of vision. Other conditions causing loss of vision found on other pages.Stroke (Cerebrovascular accident, or CVA).
Links to Symptom and Diagnosis pages based on these other symptoms are included as well. Many other eye problems can cause a loss of vision along with other symptoms.
These conditions are discussed on the Blurred Vision page. Many things that cause blurred vision can also cause a loss of vision, if the condition is severe enough. With these symptoms, there is almost always a cause for the visual loss other than a simple change in glasses. There may be large blind spots in the vision, or the appearance that something is blocking the vision. Here, loss of vision refers to a severe blurring of the vision in one or both eyes often to the point that almost no detail can be made out. At the New York Stock Exchange and bond market, though, trading was able to continue thanks to backup generators.Loss of Vision Ocular Symptoms and Conditions: Loss of VisionĪ loss of vision can be a frightening experience, and all people with a sudden loss of vision should be seen by an ophthalmologist as an emergency. There were even some reports of people being stranded mid-ride on amusement park roller coasters. The loss of use of electric water pumps interrupted water service in many areas. Small business owners were affected when they lost expensive refrigerated stock. In New York City, it took more than two hours for passengers to be evacuated from stalled subway trains. The outage stopped trains and elevators, and disrupted everything from cellular telephone service to operations at hospitals to traffic at airports. Although power companies were able to resume some service in as little as two hours, power remained off in other places for more than a day. Fifty million people were affected, including residents of New York, Cleveland and Detroit, as well as Toronto and Ottawa, Canada. ET, 21 power plants shut down in just three minutes. A major outage knocked out power across the eastern United States and parts of Canada on August 14, 2003.