RÉSUMÉ
A randomized double-masked single drop instillation clinical trial was conducted on 60 healthy volunteers divided into 3 equal groups to compare the efficacies of centbucridine and lignocaine. One eye of each volunteer was instilled with a single drop of either 0.5% centbucridine hydrochloride, 1% centbucridine hydrochloride or 4% lignocaine hydrochloride, with the other eye as an unanaesthetized control-side effects, if any, were also recorded. The onset of anaesthesia assessed both objectively and subjectively, was quickest with lignocaine 4% (P < 0.001) followed by centbucridine 0.5% and 1%. However, the period of peak activity as well as the total duration of surface anaesthesia, and also the depth of analgesia, were significantly highest with 1% centbucridine, followed by 0.5% centbucridine and 4% lignocaine respectively. Minor side effects like burning sensations were longest with 1% centbucridine--no significant adverse effects, local or systemic, were observed. Prolonged surface anaesthetic and analgesic actions of centbucridine 1% may be advantages for longer duration ophthalmic microsurgeries.