Unilateral Vision Loss after Prolonged Prone Position in Spinal Surgery.

A 68 year old male developed unilateral vision loss after prolonged spinal surgery under general anesthesia in prone position. Left eye examination revealed hand movements close to face, proptosis, afferent papillary defect and complete ophthalmoplegia. Despite prompt medical treatment vision had deteriorated but there was an improvement in eye movements and fundus showed a pale optic disc at 4 weeks follow-up. Postoperative visual loss (POVL) is a rare but serious complication with an estimated incidence of 0.01–1% after non-ocular surgery. The known causes for POVL are ischaemic optic neuropathy, central retinal artery occlusion and cortical blindness. We suspect the potential aetiological factor for POVL in our case is ischemic optic neuropathy due to prolonged compression of orbital contents.