What is an Eye Stroke?
Ischemic optic neuropathy (ION), also called an eye stroke, is a dangerous condition that occurs secondary to a lack of sufficient blood flow to the tissues of the optic nerve. ION is divided into anterior and posterior forms by the presence or absence of optic disc swelling, respectively. Ischemic optic neuropathies (IONs) are the most frequent acute optic neuropathy in patients older than 50 years.
- An eye stroke, also called ischemic optic neuropathy, is a dangerous condition caused by a lack of blood flow to the optic nerve.
- Eye stroke risk factors include age, cardiovascular disease, or a small, crowded optic nerve.
- If one eye has an eye stroke, there is a 30% chance of an eye stroke in the fellow eye so cardiovascular disease control is key.
Understanding an Eye Stroke
Ischemic optic neuropathy (ION) describes a state of hypoxic injury of the optic nerve. While an eye stroke can occur from a total blockage of the blood vessel that supplies the optic nerve, it is more commonly caused by a lack of blood in the eye tissue. If the nerve tissue is damaged due to a lack of nutrients and oxygen, sudden vision loss may occur.
Risk Factors for an Eye Stroke
Age is the most important risk factor for an eye stroke. Only 10% of those who suffer from an eye stroke are under the age of 45. Cardiovascular disease is the second most important risk factor. In some patients with cardiovascular disease, blood pressure falls significantly while sleeping. Low blood pressure reduces circulation through arteries, increasing the risk of an eye stroke.
A small, crowded optic nerve is also a risk factor. In a small optic nerve, the nerve fibers that connect the eye to the brain become crowded within the disc increasing the risk of occlusion.
Symptoms of Eye Stroke
The symptoms of an eye stroke occur quickly and without pain. Symptoms include:
- Loss of vision in one eye upon waking
- A dark shadow in the upper/lower half of the visual field
- Loss of visual contrast
- Light sensitivity
Diagnosing Eye Stroke
An eye stroke can be diagnosed by an eye exam. An eye doctor will check your central and peripheral vision. By dilating your eyes, they are able to view the retina, and the optic nerve and compare the affected eye to the normal eye. A doctor will also review your medical history and ask about cardiovascular diseases such as diabetes, hypertension, and cholesterol.
Eye Stroke Treatment
Steroids improve vision in individuals who have had an eye stroke if they are initiated quickly after the incident. Corticosteroids reduce the leaking of blood vessels, and improve swelling and circulation. Sometimes glaucoma drops will be prescribed to improve blood flow to the optic nerve. There is some early research on neuro-protection medications that may regenerate nerve fibers to the optic nerve, but there is not any conclusive evidence. Controlling cardiovascular disease is important as there is a 30% chance that an eye stroke can occur in the other eye.