Randomised prospective masked study comparing patient comfort following the instillation of topical proxymetacaine and amethocaine.

AIMS To evaluate the claim that topical proxymetacaine produces little or no discomfort on instillation by comparing it against topical amethocaine. METHODS This randomised, masked, double blind, prospective study involved 53 consecutive patients. Each patient received one drop of amethocaine 0.5% in one eye and one drop of proxymetacaine 0.5% in the other. The duration of the stinging sensation and degree of discomfort (using descriptive and a linear analogue method) for each topical anaesthetic was assessed. RESULTS The mean duration of stinging was 3.2 seconds for proxymetacaine and 22.1 seconds for amethocaine the difference being statistical significant (p < 0.001). The mean descriptive discomfort score was 2.6 for proxymetacaine and 14.2 for amethocaine (p = 0.01). The mean linear analogue score was 5.8 for proxymetacaine and 35.6 for amethocaine (p < 0.001). Proxymetacaine had a successful tonometry rate of 93% and amethocaine 98%. CONCLUSION This clinical study confirms that proxymetacaine is more comfortable on instillation than amethocaine. Minimising unnecessary patient discomfort is not only ideal, but encourages cooperation in apprehensive patients especially in children.