Lidocaine 2% gel versus lidocaine 4% unpreserved drops for topical anesthesia in cataract surgery: A randomized controlled trial

Abstract

Objective To compare intracameral levels and clinical efficacy of lidocaine 2% gel with lidocaine 4% unpreserved drops. Design Double-blind, randomized, one-surgeon, controlled trial. Participants One hundred seven consecutive cataract cases eligible for topical anesthesia. Intervention Patients were randomly assigned to receive 20 mg of lidocaine either as lidocaine 2% gel (1 ml) or as lidocaine 4% unpreserved eyedrops (0.5 ml) before clear corneal phacoemulsification. Main outcome measures Aqueous samples were taken to measure lidocaine intraocular levels. Intraoperative pain was quantified a few minutes after surgery using a 0 to 10 visual analog scale. Secondary outcome measures Patients were asked to grade the degree to which they were bothered by tissue manipulation. The surgeon graded patients’ cooperation. The anesthesiologist recorded any increase in pulse or blood pressure and the need for supplemental topical anesthesia or intravenous sedation. Duration of surgery and intraoperative complications were also recorded. Results In the gel group intracameral lidocaine levels were significantly higher ( P < 0.001) and patient-reported intraoperative pain scores were significantly lower ( P = 0.026). Patients in the gel group were bothered by tissue manipulation to a lesser extent ( P = 0.028), and their cooperation was better ( P = 0.002). Increases in blood pressure were more frequent in the eyedrops group. Supplemental anesthesia was required in two cases (3.70%) in the gel group versus eight cases in the eyedrops group (15.09%). No correlation between intracameral lidocaine levels and intraoperative pain scores was found ( r = −0.026, P = 0.789). Conclusions If administered by means of gel, the same amount of lidocaine gives significantly higher intracameral levels of lidocaine, better analgesia, better patient cooperation, and less need for intraoperative supplemental anesthesia. Lower pain scores do not correlate with intracameral lidocaine levels.