Arterial Occlusion

The eye is like a camera, there are lenses in the front of the eye that focus the image onto a light-sensitive membrane in the back of the eye known as the retina. The retina is like the film in a camera. The retina gets much of its oxygen and nourishment from the blood vessels within it. There are two major types of blood vessels in the retina. There are arteries which bring blood into the retina and veins which bring blood out of the retina.

Occasionally a retinal artery may become blocked or occluded. When this happens the vision may be affected a lot, a little or not at all depending on where the occlusion occurs. When an artery becomes occluded, the cause of the occlusion is usually a solid particle floating in the blood stream which becomes stuck in an artery blocking it. This particle flowing from one area in the body to another is known as an embolus. Emboli most commonly arise from an artery in the neck known as the carotid artery, from the aortic arch (the largest blood vessel in the body) or from the heart. Emboli may arise from other parts of the body as well. If the embolus consists of cholesterol, the embolus is known as a Hollenhorst plaque. Other emboli may be composed of blood products such as platelets and fibrin and still other emboli may contain calcium, fat, bacteria, or foreign particles that have been injected into the blood stream. Occasionally an artery may become blocked due to spasm. This may occur due to a migraine headache or due to an inflammatory disease of the artery.

Following a partial or a complete retinal artery occlusion, your doctor will try to determine the cause of the occlusion. This may include an echocardiogram (taking a picture of the heart using sound waves), a carotid duplex scan (taking a picture of the blood vessels in the neck using sound waves), and various blood tests. Your medical doctor or a vascular specialist will review the results of these tests with you and discuss possible treatment options or further diagnostic tests depending on what is found.

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