Comparison of lidocaine 2% gel versus retrobulbar anaesthesia for implantation of Ahmed glaucoma drainage.
PURPOSE: To compare patient comfort and the efficacy of lidocaine 2% gel versus retrobulbar anaesthesia for Ahmed glaucoma implant surgery. PATIENTS AND METHODS: This prospective study included 32 eyes of 32 patients scheduled to undergo implantation of an Ahmed glaucoma drainage device for refractory glaucoma in one institution, randomized to receive either topical lidocaine 2% gel or retrobulbar anaesthesia. Sixteen eyes were randomized to each group. Patient assessment of pain was recorded during delivery of anaesthesia, during surgery and after surgery, using a visual analogue pain scale. The need for additional anaesthesia during tissue manipulation was recorded. Surgeon assessments of operative conditions, patient co-operation and intraoperative complications were also recorded. RESULTS: The patients in the retrobulbar group reported significantly more discomfort during administration of the anaesthetic agent than the patients in the topical anaesthesia group (p = 0.000). There was no significant difference in patient-reported pain scores intraoperatively (p = 0.317) or postoperatively (p = 0.875). Surgeon assessment showed similar levels of patient co-operation in both groups (p = 0.615). The overall operating conditions were overwhelmingly positive in each group (p = 0.186). The mean duration of surgery was significantly longer in the topical group compared with the retrobulbar group (p = 0.049). CONCLUSIONS: Lidocaine 2% gel is a safe alternative to retrobulbar anaesthesia for Ahmed drainage implant surgery and avoids the significantly greater pain associated with the administration of retrobulbar anaesthesia. It provides a reasonably safe and comfortable surgical environment and is well tolerated by patients.