BACKGROUND: Posterior ischemic optic neuropathy (PION) is a rare cause of bilateral severe and bilateral visual loss. Three mechanisms for posterior ischemic optic neuropathy are recognized: arteritic, non-arteritic, and peri- or postoperative. We report a case of bilateral postoperative posterior ischemic optic neuropathy. HISTORY AND SIGNS: A previously healthy 51-year-old man complained of the sudden onset of visual loss and unformed visual hallucinations in both eyes, 24 hours after an uneventful lumbar spine surgery. Duration of surgery was 12 hours with 2.5 liters of blood loss. At the time of visual loss, anemia was 74 g/L. Ophthalmic examination revealed decreased visual acuity to count fingers and normal optic disc without swelling or hemorrhages in both eyes. THERAPY AND OUTCOME: Despite blood transfusion 2 days after visual loss, evolution was stable. One month later, visual acuity was 0.15 RE and 0.2 LE with severe dyschromatopsia. Pupils reacted sluggishly to light but briskly to convergence. Optic discs were diffusely pale. DISCUSSION: Peri- and postoperative posterior ischemic optic neuropathy is a rare but devastating complication of surgery performed at distance from the visual pathways and its vascularization. Risk factors include: spine surgery, peri-operative hypotension, anemia, facial edema. Early recognition of posterior ischemic optic neuropathy and rapid correction of hypotension and/or anemia might improve outcome of posterior ischemic optic neuropathy, which usually is poor.