PION
Pronunciation: PEE-on
Also written as: PION — Posterior ischemic optic neuropathy
Posterior ischemic optic neuropathy; vision loss due to ischemia of the posterior optic nerve.
Full Definition
Posterior ischemic optic neuropathy (PION) is a rare condition characterized by ischemia to the posterior portion of the optic nerve, behind the globe where the nerve is not visible on fundoscopy. Unlike anterior ischemic optic neuropathy, the optic disc initially appears normal despite significant vision loss. PION can be arteritic (associated with giant cell arteritis) or non-arteritic, and has been reported in association with severe blood loss, hypotension, or certain surgical procedures.
Usage
Usage note: Unlike anterior forms, the optic disc appears normal initially in PION.
In Context
- "The patient developed PION following prolonged spinal surgery in the prone position." — Perioperative complication report
- "PION was suspected when the patient had severe vision loss with a normal-appearing optic disc." — Diagnostic workup