Painless visual loss. Most commonly occurs in the postoperative setting at any time from upon awakening from anesthesia to 4 to 7 days thereafter. May be unilateral or bilateral, with a partial or complete deficit.

See 10.18, NONARTERITIC ISCHEMIC OPTIC NEUROPATHY. Optic discs may appear normal initially in acute posterior ischemic optic neuropathy, but eventually pale disc edema, followed by pallor, develops.

• Postoperative: May occur after head and neck surgery, spinal surgery, gastrointestinal surgery, open heart surgery, or any procedure associated with hypotension, anemia, increased surgical time, large amounts of blood loss, increased central venous pressure, or positioning of head in a dependent, down-tilt position. History of peripheral vascular disease, diabetes, and anemia may increase risk.
• Inflammatory/infectious: GCA, varicella zoster virus, systemic lupus erythematosus, and others.

NOTE:

Operative planning in high-risk patients should include attention to head positioning and length of surgical time, balance of risk and benefits of hypotensive anesthesia, aggressive replacement of blood loss, monitoring vision early in the postoperative period, and prompt ophthalmic consultation if patient describes visual disturbances.

1. Although no controlled studies exist for postoperative posterior ischemic optic neuropathy, it has been suggested that prompt blood transfusion with correction of hypotension and anemia may be beneficial and should be considered.
2. Treat any inflammatory or infectious etiology as appropriate.