Comparison of sub-Tenon's anaesthesia by different delivery techniques in cataract surgery

Purpose To compare the analgesic effects of three different delivery techni ques of sub-Tenon's anaesthesia in cataract surgery by assessing patients' response to the visceral stimulus. Methods A prospective, randomised study was conducted on 345 eyes of 845 pa tients undergoing phacoemulsification and posterior chamber intraocular len s implantation. They received anaesthetic infiltration into the sub-Tenon's space through a conjunctival incision (115 eyes), infiltration into the po sterior sub-Tenon's space (retrobulbar space) through a conjunctival incisi on (114 eyes), or injection into the intra-Tenon's space (subconjunctival s pace) without making a conjunctival incision (116 eyes). Pain scores were r ecorded when the anterior chamber was irrigated with an acetylcholine chlor ide solution to achieve miosis after lens implantation. Results There were no significant differences in pain scores among the thre e groups (chi-squared test of homogeneity p = 0.814). Approximately 10 -20% of patients reported slight to severe: pain at the time of acetylcholine a dministration. Conclusions The three anaesthetic delivery methods of sub-Tenon's anaesthes ia possess similar and reasonable analgesic effects in cataract surgery, bu t may not block visceral stimuli completely.