We attempted to determine the efficacy of perilimbal anesthesia with Monitored Anesthesia Care (intravenous sedation with monitoring of the patients' vital signs by anesthesia) in patients undergoing pars plana vitrectomy. We selected 15 patients who were screened for any physical condition that would preclude them from lying supine and motionless for the duration of the surgery. Patients with complicated vitreoretinal abnormalities and patients who required reoperations were excluded. The patients ranged in age from 55 to 79 years and included three with nonclearing vitreous hemorrhage, seven with macular hole, three with macular pucker, one with proliferative diabetic retinopathy, and one with endophthalmitis. Total operating time ranged from 45 to 135 minutes (mean, 102.3 +/- 22.0 minutes). No complaints of discomfort were reported. All operations were completed without additional anesthetic. Our findings demonstrate that pars plana vitrectomy using perilimbal anesthesia with monitored anesthesia care is effective in selected patients. This form of anesthesia administration eliminates the risks of inadvertent globe perforation associated with retrobulbar and perilimbal anesthesia and the risks of general anesthesia.