Korean J Ophthalmol Vol.20, No.2, 2006 Fig. 1. Ocular fundus photography on the second postoperative day. The right eye shows a pale optic disc with an edematous retina and a cherry-red spot on the fovea. Fig. 2. Fluorescein angiogram on the second postoperative day. The right eye shows an extreme delay in arterial filling time. trigeminal nerve, afferent pupillary defect, and total ophthal- moplegia. Intraocular pressure was within the normal range. Anterior segments were normal in both eyes. He had a pale optic disc with an edematous retina and fundus examination revealed a cherry-red spot on the fovea (Fig. 1). His fluore- scein angiographic examination revealed a delayed arterial filling time (Fig. 2). His brain MRI and magnetic resonance angiography (MRA) findings were normal with no evidence of embolic phenomena. However we noted mild swelling of the right periorbital soft tissue and edema of the extraocular muscles in the right eye, sparing their tendons (Fig. 3). Ptosis, the afferent pupillary defect, and ocular movement improved over three postoperative days, but despite medical treatment with carbonic anhydrase inhibitors and corti- costeroids, the patient had optic atrophy on the following examination (Fig. 4). Eventually his vision deteriorated until he had no light perception after the last follow up at three months. 140 Fig. 3. T2-weighted image of orbital MRI shows mild periorbital swelling and edema of the extraocular muscles in the right eye, with the tendons spared. Fig. 4. Ocular fundus photography after three months. The right eye shows optic atrophy. Discussion Postoperative visual loss following non-ocular surgery is an infrequent but disastrous complication with an estimated incidence ranging from 0.001 to 1% depending on the type of surgery.6,7 A survey of vision loss after spinal surgery has suggested that possible intraoperative causes including patient positioning, blood loss, and intraoperative hypotension could be responsible for this complication. The three recognized causes of postoperative visual loss are ischemic optic neuro- pathy, central retinal artery or vein occlusion, and cerebral ischemia.8,9 In addition to speculation regarding the intraoperative