What Is a Stroke in the Eye?

An eye stroke can be a frightening experience, as it seems to occur suddenly without warning, and can have visually devastating results. Eye strokes affect the optic nerve, which is crucial to the eye and its functions, containing over 1.2 million nerve fibers, according to doctors Richard and Laura Windsor of The Low Vision Centers of Indiana.

Significance

• Eye strokes, or anterior ischemic optic neuropathy (AION), results in varying degrees of vision loss, and in extreme cases, total loss of vision. Eye strokes occur with little or no warning in one eye, and then, over time, progress into the other eye.

How Eye Strokes Occur

• When a blockage (called an occlusion) occurs in the blood vessels that supply the front of the optic nerve, an eye stroke occurs, as there is a cutoff in nutrient and oxygen supply. Without nutrients and oxygen, nerve tissue is damaged and lost, resulting in vision loss.

Causes

• In addition to trauma of the head or eye injury, many causes are associated with AION: glaucoma, giant cell arteritis, lupus, Buerger's disease, allergies, post-viral vasculitis, post-immunization, smoking, high blood pressure, syphilis, hypertension, migraines, diabetes, atherosclerosis, carotid occlusive disease, sickle cell disease, and acute hypotension.

Symptoms

• Sudden vision loss (subject to worsening) is the major symptom, and of varying degrees. For 90 percent of AION sufferers, according to "Optic Neuropathy, Anterior Ischemic," on eMedicine, the visual loss is painless and noticed upon waking up.

Types

• Non-arteritic and arteritic are the two types of AION, non-arteritic being the more common form that yields the best visual outcome. Symptoms of arteritic AION are more severe, and the cause is typically giant cell arteritis, a deadly disease.

Treatment

• Dr. Richard and Laura Windsor report that options for treating the optic nerve directly are limited. Lowering intraocular pressure for pain reduction and nerve protection are common steps.