comparison of low volume transconjunctival anterior peribulbar anesthesia with transcutaneous posterior peribulbar anesthesia

purpose: to compare low volume transconjunctival anterior peribulbar anesthesia with transcutaneous posterior peribulbar anesthesia in phacoemulsification. methods: patients scheduled for phacoemulsification were randomly divided into two groups: in first group 5ml of 2% lidocaine was injected transcutaneously in the posterior orbital space. in the second group, 2ml of 5% lidocaine was injected transconjunctivaly in the anterior orbital space. pain during injection, pain during surgery and akinesia at the beginning of surgery were compared in two groups. results: 383 patients were enrolled in the study, 179 were allocated in the first group and 204 patients were assigned to the second group. average pain level during injection was 1.42 ±1.1 in the first group and 0.7 ±0.3 in the second group (p= 0.0001). average pain level during surgery was 1.1 ±0.6 in the first group, and 1.5 ±1.3 in the second group (p= 0.0001). average akinesia at the beginning of surgery was 1.3 ±1.1 in the first group and 2.3 ±0.7 in the second group (p= 0.00001). serious complications such as perforation of the globe or orbital hemorrhage were not observed in either study group. intraoperative posterior capsular rupture happened in 2 cases in the first group versus 3 cases in the second group. conclusion: low volume transconjunctival anterior peribulbar anesthesia in comparison with transcutaneous posterior peribulbar anesthesia has less pain during injection but is associated with higher pain during surgery and lower akinesia at the beginning of surgery. this method can be used for patients with high myopia, because of the very low risk of globe perforation.