Intraocular Pressure During Abdominal Aortic Aneurysm (AAA) Repair

The objective of this study will be to answer a clinical question that has not already been investigated; that is, what are the effects of aortic infra-renal clamping and unclamping on intraocular pressure during Abdominal Aortic Aneurysm (AAA) repair? Depending on the results, this study may raise or alleviate concern that vascular surgery for abdominal aortic aneurysm could contribute to early perioperative exacerbation of pre-existing eye disease and increase a patient's vulnerability to developing a type of blindness known as ischemic optic neuropathy. The purpose of this observational study is to evaluate whether intraocular pressure measurements with a handheld tonometer will detect changes in intraocular pressure related to intraoperative events during aortic cross clamping and unclamping that may provide information on causes of perioperative blindness.