Anterior ischemic optic neuropathy

Anterior ischemic optic neuropathy (AION) is a medical condition involving loss of vision due to damage to the optic nerve from insufficient blood supply. It can be subdivided into two types: arteritic AION (or AAION) and non-arteritic AION (or NAION) see below.

Overview

The optic nerve, which can be damaged in AION

AION is caused by a problem with the blood supply to the optic nerve. The optic nerve carries visual information from the eye to the brain, and damage to this nerve can result in vision loss. The anterior part of the optic nerve, which is visible on the surface of the retina, is the part most commonly affected in AION.

Symptoms

The main symptom of AION is sudden, painless vision loss in one eye, which can range from mild to severe. Other symptoms can include a small visual field defect (a 'blind spot'), and on examination, a swollen optic disc may be visible.

Causes

The exact cause of AION is not known, but it is thought to be related to conditions that can affect the small blood vessels, such as hypertension, diabetes, and atherosclerosis. In some cases, it may be associated with giant cell arteritis.

Types of AION

There are two main types of AION: arteritic AION (AAION) and non-arteritic AION (NAION).

Arteritic AION (AAION)

AAION is caused by an inflammation of the arteries (arteritis), most commonly giant cell arteritis. This condition is a medical emergency, as it can lead to complete blindness if not treated promptly.

Non-Arteritic AION (NAION)

NAION is the more common type of AION. It is often associated with systemic conditions like hypertension, diabetes, and atherosclerosis.

Treatment

Treatment for AION depends on the type. For AAION, immediate treatment with high-dose corticosteroids is usually required to prevent further vision loss. For NAION, treatment is mainly supportive, and may include measures to control any underlying conditions, such as hypertension or diabetes.

See also

• Optic neuropathy
• Giant cell arteritis
• Optic nerve