Ischemic Optic Neuropathy

Blockage of the blood supply to the part of the optic nerve within the eye can lead to impaired function of optic nerve cells and vision loss. Two types can occur: nonarteritic and arteritic.

Nonarteritic ischemic optic neuropathy occurs more frequently and usually occurs in people about age 50 and older. Vision loss is not usually as severe as in arteritic ischemic optic neuropathy. Risk factors include an anatomically congested optic nerve (small cup-to-disc ratio), high blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more , smoking Smoking Smoking tobacco is harmful to almost every organ in the body. Smoking increases the risk of heart attack, lung cancer, chronic obstructive pulmonary disease (COPD), and other disorders. Nicotine... read more , diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , and atherosclerosis Atherosclerosis . Other risk factors may include obstructive sleep apnea Sleep Apnea Sleep apnea is a serious disorder in which breathing repeatedly stops long enough to disrupt sleep and often temporarily decrease the amount of oxygen and increase the amount of carbon dioxide... read more , use of certain drugs (for example, amiodarone and possibly phosphodiesterase-inhibiting drugs, such as sildenafil, which are used to treat erectile dysfunction Erectile Dysfunction (ED) Erectile dysfunction (ED) is the inability to attain or sustain an erection satisfactory for sexual intercourse. (See also Overview of Sexual Dysfunction in Men.) Every man occasionally has... read more ), a tendency to develop blood clots, and low blood pressure at night.

Arteritic ischemic optic neuropathy usually occurs in people about age 60 and older. The blood supply to the optic nerve is blocked due to inflammation of the arteries (arteritis), most notably giant cell arteritis Giant Cell Arteritis Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide... read more .

Loss of vision is usually rapid (over minutes, hours, or rarely days) but is painless. Depending on the cause, vision may be impaired in one or both eyes. Vision in the involved eye or eyes can range from almost normal to complete blindness.

People with giant cell arteritis Giant Cell Arteritis Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide... read more tend to be older, and their loss of vision tends to be more severe. They may have jaw pain when they chew, headaches, muscle aches and pains, and scalp pain when they comb their hair.

Diagnosis involves examination of the back of the eyes with a light with magnifying lenses (ophthalmoscope) and a visual field examination to measure central or peripheral vision loss. The head of the optic nerve at the back of the eye (optic disc will be swollen. Determining the cause involves determining whether the person has any of the disorders known to be risk factors.

If giant cell arteritis Giant Cell Arteritis Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide... read more is suspected as a cause, blood tests are done and corticosteroids are started immediately to prevent further vision loss. Removal and examination of a temporal artery tissue sample under a microscope (biopsy) may be done to confirm the diagnosis. Blood tests determine the erythrocyte sedimentation rate (ESR), the C-reactive protein level, and the levels of certain types of blood cells (complete blood count). Results of these tests may indicate inflammation that is characteristic of giant cell arteritis. If a person has no symptoms of giant cell arteritis, magnetic resonance imaging (MRI) or computed tomography (CT) of the brain may be done to make sure the optic nerve is not being compressed by a tumor.

Other tests may be necessary depending on what causes are likely. For example, if people have symptoms of obstructive sleep apnea (such as excessive daytime sleepiness or snoring), polysomnography Testing may be done. If people have had blood clots, blood tests may be done to diagnose blood-clotting disorders.

There is no effective treatment for nonarteritic ischemic optic neuropathy. However, about one third of people with nonarteritic ischemic optic neuropathy have partial improvement of their vision spontaneously. In this condition, repeat episodes in the same eye are rare, but the other eye is affected in 15 to 20% of people.

In the arteritic variety caused by giant cell arteritis Giant Cell Arteritis Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide... read more , vision loss is typically greater than in nonarteritic ischemic optic neuropathy. Prompt treatment with corticosteroids does not restore lost vision in the affected eye but protects the unaffected eye. Inadequate treatment increases the risk of vision loss in the other eye.

In people with nonarteritic ischemic optic neuropathy, treatment to restore vision loss is ineffective. Treatment involves reducing risk factors for atherosclerosis Atherosclerosis , including controlling blood pressure and diabetes. Other causes, such as blood-clotting disorders and obstructive sleep apnea, may also require treatment.

In people with arteritic ischemic optic neuropathy caused by giant cell arteritis, high doses of corticosteroids are given by mouth and/or vein as soon as possible to prevent loss of vision in the other eye. Adding tocilizumab (a drug that decreases inflammation) to corticosteroids has recently been shown to help people with giant cell arteritis Giant Cell Arteritis Giant cell arteritis is chronic inflammation of large and medium arteries of the head, neck, and upper body. Typically affected are the temporal arteries, which run through the temples and provide... read more .

Magnifiers, large-print devices, and talking watches (low-vision aids) may help people with loss of vision.