When patients suddenly lose vision they are often told they suffered a "stroke" in their eye. There are actually many reasons why this event can happen. One common cause is a closure or a clot that develops in the main vein that drains the eye. If the whole vein is involved it is known as a central retinal vein occlusion. Sometimes only a branch of this vein is blocked in which case it is called a branch vein occlusion. Central vein occlusions in younger people may be caused by inflammation. They usually have a better prognosis and may be helped by antiinflammatory drugs such as cortisone. In older patients vein occlusions are often associated with arteriosclerotic heart disease and such problems as hypertension and diabetes should be ruled out. While these occlusions can result in severe visual loss they can respond to treatment with vascular endothelial growth inhibitors, injectable steroids, and sometimes laser.
The arteries that feed blood and oxygen to the eye can also be clogged. Like vein occlusions they can be termed central retinal artery occlusions if the whole artery is involved or branch artery occlusions if only a branch of the artery is involved. These are usually caused by pieces of cholesterol breaking off from an artery, usually the carotid artery in the neck. Medical work-ups for this problem should be done quickly as more plaques could break off and these can lead to a serious stroke. There are various ways to treat this problem ranging from breathing into a paper bag, to digital massage, and sometimes even inserting a needle into the eye and then aspirating fluid known as the aqueous humor. More recently clot busting drugs known as thrombolytic drugs such as tissue plasminogen activator (t-PA) can be used. This works best when given within 6 hours of the event and should be administered in a stroke unit of a hospital as there can be some risk in administering this medication. It should also be mentioned that with all central artery occlusions temporal (giant cell) arteritis should be ruled out as this condition can lead to loss of vision in the other eye as well.