The frequency of post-operative permanent vision loss has been recently estimated to be 1:61,0001,2 , although the majority of these cases involve surgical trauma to the eye or brain. Prolonged vision loss not attributable to direct trauma has been estimated to occur with a frequency of approximately 1:125,0003 and has been given a broad classification termed ischemic optic neuropathy. This rare but catastrophic outcome has most commonly been associated with operations performed under circumstances in which there may be increased intraocular pressure (IOP), either due to positioning4 or due to insufflation of the abdomen with carbon dioxide (laparoscopy).5