Ischemic Optic Neuropathy

Stroke of the optic nerve, sudden painless vision loss

Overview

Ischemic optic neuropathy is damage to the optic nerve caused by an inadequate blood supply, sometimes described as a stroke of the optic nerve. The most common form is anterior ischemic optic neuropathy, which affects the optic nerve head and produces sudden, painless vision loss in one eye, often with loss of the upper or lower half of the visual field and a swollen optic disc. Nonarteritic anterior ischemic optic neuropathy, NAION, is the commoner type and is associated with a small, crowded optic disc, hypertension, diabetes, and obstructive sleep apnea. Arteritic anterior ischemic optic neuropathy is caused by giant cell arteritis, an inflammation of medium and large arteries in older adults that can also cause headache, scalp tenderness, and jaw pain when chewing. Arteritic disease is regarded as a medical emergency because without prompt corticosteroid treatment the other eye is at substantial risk. Posterior ischemic optic neuropathy, affecting the nerve further behind the eye, is rarer and can follow major surgery.