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Background: Cataract surgery is mainly performed under topical anesthesia achieved either by tetracaine solution (0.5%–1.0%) or gel (0.5%), or by 2% lidocaine gel. This paper reviews the current knowledge about these two drugs, with special emphasis on a published prospective comparison between them.
Methods: The main pharmacological aspects of topical anesthetic agents are summarized, explaining the difference between the ester (tetracaine) and the amide (lidocaine) compounds. Tetracaine is available as single-use eye drops, or as a multidose gel containing benzalkonium chloride, a preservative not contained in the multidose lidocaine gel. A literature search was performed, using “tetracaine”, “tetracaine gel”, “lidocaine”, “lidocaine gel”, “lidocaine jelly”, and “cataract surgery” as keywords, and compiling cross-references. A total of 25 studies were identified and included in this review. Of them, seven were uncontrolled studies describing different experiences with the drugs of interest, and 18 were controlled studies. Six studies directly compared tetracaine eye drops or gel with lidocaine gel before cataract surgery.
Results: Both tetracaine solution and gel and lidocaine gel proved to be effective in providing analgesia before cataract surgery. Both drugs were comparable with needle injection anesthesia when intracameral lidocaine was added to topical treatment. Direct comparisons indicate better activity for tetracaine when used at the 1% concentration in single-dose units, or in the gel form at a 0.5% concentration. Patients showed a slight preference for the agent that caused the least discomfort when administered (lidocaine), while the surgical complication rate and the surgeon satisfaction were the same with either drug.
Conclusion: Tetracaine solution and lidocaine gel were equally effective in providing topical anesthesia for cataract surgery in the published studies. Tetracaine was found to be better than lidocaine only if augmented by either increasing the concentration to 1% (solution) or by increasing the penetration by adding benzalkonium chloride (gel).