By means of a recently developed electronical optical esthesiometer the efficacy of five different topical anaesthetics was compared. The influence of vehicle and concentration was also investigated. From the results it can be concluded that the drugs currently available are of suitable local anaesthetic effect with little influence of the vehicle or preservative agent used.

By means of a new electronic-optical instrument corneal sensitivity after application of topical anaesthesia was examined. In a prospective study different preparations were compared, also the influence of concentration dosage and milieu were studied.