What is the most common cause of arteritic anterior ischemic optic neuropathy (AAION)?

• A. Giant cell arteritis
• B. Hypertension
• C. Hyperlipidemia
• D. Diabetes mellitus

Answer: (A)

Arteritic anterior ischemic optic neuropathy is driven by inflammatory occlusion of the arteries that feed the optic nerve head, most commonly due to giant cell arteritis. This inflammatory vasculitis damages the short posterior ciliary arteries, leading to sudden vision loss and pale, swollen discs. Hypertension, hyperlipidemia, and diabetes mellitus are vascular risk factors more closely associated with non-arteritic AION or other vascular eye diseases, not with the arteritic form. Therefore, the most common cause of AAION is giant cell arteritis.