Symptoms:

Symptoms include the sudden loss of vision in one eye. This usually only lasts seconds but may last several minutes. Some patients describe the loss of vision as a gray or black shade coming down over their eye.

Signs and tests:

Tests include a complete eye and neurological exam. In some cases, an eye exam will reveal a bright spot where the clot is blocking the retinal artery. A carotid ultrasound or magnetic resonance angiography (MRA) scan should be done to evaluate a blockage in the carotid artery.

Routine blood tests such as cholesterol and blood sugar (glucose) should be done to check your risk for atherosclerosis, which increases with high cholesterol and diabetes.