Non-Arteritic Anterior Ischemic Optic Neuropathy in Pilots.

Non-arteritic anterior ischemic optic neuropathy (NAION) is a common cause of optic neuropathy with the exact pathophysiology unknown. Risk factors include advanced age, small optic nerve head, hypertension, diabetes mellitus, and sleep apnea. High altitude is considered another risk factor, although only few cases have been reported. No cases of NAION have been reported to occur during flight. A 41-yr-old male pilot presented with vision change while performing high G-force maneuvers in an A10 fighter jet. He developed a paracentral visual field defect superiorly in the left eye. Contrasted MRI was within normal limits. The left optic nerve showed blurred margins while the right was sharp, but cupless. The left eye had similar episodes 16 mo before and 8 mo after, but not during flight. Our case may be the first reported NAION during flight in an airplane pilot. Our patient was an active U.S. Air Force pilot whose second episode of NAION occurred while performing maneuvers in a fighter jet. The patient is younger than expected for NAION and he did not have any of the commonly associated risk factors. His nonflight episodes suggest he was predisposed to NAION. G-force maneuvers, which restrict blood flow and force blood to the extremities away from the optic nerve head, were the precipitant of his second NAION. With a single case, whether high G maneuvers in general are a risk factor for NAION is unknown.