EYE STROKE – also known as ischemic optic neuropathy
In general stoke occurs when sufficient blood supply to an organ or part of it is cut off due to blockage or collapse of the blood supplying artery to that organ such as the event happening in brain stroke( infarction or bleed ) . In some conditions this happens in the eye at the optic nerve ( this nerve is formed by the fine axons of the retinal cells and convey the visual information to the brain to be interpreted and perceived) .As all strokes the condition is sudden , and patient will notice vision loss of some sort. There is no pain or any discomfort except for visual problem. This condition also called ischemic optic neuropathy is infarct of the optic nerve head which is situated very close to the macula. In infarction oxygen and glucose supply is stopped and always this event in the nervous tissue causes edema ( swelling) of the optic nerve head. Stroke ( infarct ) of the optic nerve can be associated with : 1- Arteriosclerosis of the small arteries, diabetes, high blood pressure, smoking, coronary heart disease and high cholesterol. In some cases high intra-ocular pressure ( even rarely following cataract surgery if the eye pressure had gone up ) or farsightedness is the causing factor .This type is called nonarteritic.
2- Arteritic stroke is due to a systemic arterial disease ( giant cell arthritis ) which causes inflammation of the arteries leading to narrowing and eventually obstruction of the lumen of the artery in different parts of the body resulting in infarction in the involved tissue. This process of inflammation can happen in the very fine arteries of the optic nerve head and sudden loss of vision and swelling of the nerve which is usually not reversible. This type of optic nerve stroke is quite serious and an eye exam should be done as soon as possible and if a diagnosis of this condition is suspected biopsy of the arteries of both temples , blood tests should be done to confirm the diagnosis and the treatment which is high steroids begun. This disease occurs in elderly people, especially in white females. Because the disease is systemic , the symptoms and signs of the involvement of other parts of the body also may be present. These include headache, tenderness of the scalp in the temple region, jaw pain on chewing, loss of appetite , weight loss, pain in the calves on walking one or two blocks and so on.