ANNANDALE EYE CARE

Anterior Ischemic Optic Neuropathy

Anterior ischemic optic neuropathy (AION) is a condition characterised by damage to the optic nerve head due to poor blood supply. The optic nerve transmits visual information from the eye to the brain, acting as a power cord. The optic nerve head can become damaged when blood flow is reduced or blocked, leading to various degrees of vision loss. AION can be further classified into two types:

Types of Anterior Ischemic Optic Neuropathy

Non-arteritic anterior ischemic optic neuropathy (NAION)

This is the more common form of AION and typically occurs in individuals who have reached middle age. It is often associated with small vessel disease and risk factors include hypertension, diabetes, high cholesterol, smoking and sleep apnoea. An optic nerve head which appears ‘crowded’ is another important risk factor.

Arteritic anterior ischemic optic neuropathy (AAION)

This form of AION is less common but more severe. It is primarily caused by inflammation of the arteries supplying blood to the optic nerve, usually due to giant cell arteritis (GCA), causing inflammation of medium and large arteries. GCA is more prevalent in elderly individuals and can lead to significant vision loss if left untreated, as well as stroke and heart attack.

Management of AION

Management of AION depends on the underlying cause.  

NAION - Treatment primarily focuses on addressing systemic vascular risk factors to reduce the risk of further episodes. However, there is currently no established effective therapy to restore vision lost due to NAION.  

AAION - Requires urgent treatment with high-dose corticosteroids to suppress inflammation and prevent further visual loss. Treatment is typically required for 1-4 years after diagnosis. Prompt diagnosis and treatment of GCA are crucial to prevent vision loss in both eyes and other systemic complications associated with the disease.

Conclusion

AION can be a serious cause of vision impairment and requires prompt evaluation by your ophthalmologist.

Symptoms of AION

Symptoms of AION may include sudden, painless vision loss or blurring in one eye. Loss of peripheral vision causing areas of reduced or absent vision can also occur.

Arteritic AION (AAION)

Giant cell arteritis can be associated with other ocular symptoms besides vision loss., including double vision and pupil abnormalities. It also causes “whole body” symptoms such as; scalp tenderness, aching jaw pain, aching muscles & joints (often the shoulders and hips), fatigue, appetite & weight loss and night sweats.