A total of 66 patients undergoing vitreoretinal surgery (total duration < 60 minutes) using retrobulbar block, who were classified as category I-III according to the ASA (American Society of Anesthesiologists) Classification system, who were over the age of 60, and who had no cognitive dysfunction were included in the study. Exclusion criteria were as follows: contraindication for retrobulbar block, preoperative systolic blood pressure of 180 mmHg, diastolic blood pressure of above 100 mmHg, uncontrolled diabetes, body mass index ≥ 30 kg/m2, MMSE ≤ 24, advanced organ failure, or Hb < 9gr/dl.The patients were randomly divided into two groups using a sealed-envelope method: