Posterior Ischemic Optic Neuropathy

Posterior Ischemic Optic Neuropathy (PION) is a medical condition characterized by damage to the retrobulbar portion of the optic nerve due to ischemia, a restriction of the blood supply to the optic nerve. Despite the term posterior this pathophysiology may be applied to cases where the ischemic damage is anterior, as the condition describes a particular mechanism of visual loss as much as the location of damage in the optic nerve. Anterior ischemic optic neuropathy (AION) is distinguished from PION by the fact that AION occurs spontaneously and unilaterally in patients with predisposing anatomy and cardiovascular risk factors.