Efficacy of 1% versus 2% lidocaine in patients undergoing phacoemulsification under sub‐Tenon's anaesthesia

Abstract

Sub-Tenon's anaesthesia is a very safe and effective way of achieving anaesthesia and akinesia in patients undergoing cataract extraction. Various local anaesthetics and their combinations and additives are in use to achieve rapid and complete akinesia. The aim of this study was to compare the efficacy of 1% and 2% lidocaine in achieving akinesia in these patients. Fifty patients undergoing routine phacoemulsification using a clear corneal 2.8-mm incision were randomly assigned to receive 5 ml 1% lidocaine or 5 ml 2% lidoocaine, using a one-quadrant sub-Tenon's injection. A blinded observer subsequently assessed ocular akinesia at 30 s and 1, 3, 5 and 10 min, using a validated scoring system. Changes in the ocular motility scores were then compared with t-tests, chi-squared test or Mann-Whitney U test, using SPSS. There was no significant difference in the ocular motility scores at 30 s and 1 min in both groups. However by 3 min, patients in the 2% group demonstrated significantly better akinesia (Table 1). The difference was maintained at 5 and 10 min. Onset of akinesia was also faster in this group. We found that 2% lidocaine provides a better and faster onset of akinesia in patients undergoing phacoemulsification under sub-Tenon's anaesthesia.