[Perioperative visual loss after nonocular surgery]

Perioperative visual loss (POVL) after nonocular surgery is a rare but unexpected event and represents a devastating complication. It is most often associated with cardiac, spinal as well as head and neck surgery. The etiology of POVL remains incompletely understood. Any portion of the visual system may be involved, from the cornea to the occipital lobe. The most common site of permanent injury is, however, the optic nerve itself and ischemia is the most often presumed mechanism. Multiple factors have been proposed as risk factors for POVL, including long duration in the prone position, decreased ocular perfusion pressure, excessive blood loss and anemia, hypotension, hypoxia, excessive fluid replacement, elevated venous pressure, head positioning and a patient-specific vascular susceptibility which may be anatomic or physiologic. However, the risk factors for any given patient or procedure may vary. The underlying specific pathogenesis of these neuro-ophthalmic complications remains unknown and physicians should be alert to the potential for loss of vision in the postoperative period. This review updates readers on the incidence, suspected risk factors, diagnosis and treatment of POVL in the setting of nonocular surgery.