Transient Bilateral Visual Loss due to Posterior Ischemic Optic Neuropathy After Cardiac Surgery: A Very Rare Case

Visual loss is a relatively rare but devastating and unpredictable complication of open heart surgery with cardiopulmonary bypass. The most common cause of postoperative visual loss following cardiac surgery is ischemic optic neuropathy (ION), which is generally categorized as anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). PION is clinically differentiated from AION with a normal-appearing optic nerve head. PION is relatively more common in cases of spinal surgery and radical neck dissection, while AION appears to be more common than PION after cardiac surgery. We report a very rare case of transient bilateral visual loss due to PION in a 44-yearold man undergoing mitral valve replacement and coronary artery bypass graft surgery.