Efficacy of varying concentrations of hyaluronidase in peribulbar anaesthesia

We have compared the efficacy of adding varying concentrations of hyaluroni dase to a standard mixture of 2% lidocaine and 1% ropivacaine to provide pe ribulbar anaesthesia for cataract surgery. We used (i) the time to adequate anaesthesia for surgery and (ii) ocular and eyelid movement scores at 8 mi n after block as clinical endpoints. Ninety patients were randomly allocate d to receive 7-10 mi of equal volumes of 2% lidocaine and I% ropivacaine wi thout hyaluronidase or with hyaluronidase 15 IU ml(-1) or 150 IU ml(-1). Me dian time at which the block was adequate for surgery was 6 min in all grou ps (interquartile range 4-12 min). Median eyelid movement scores were simil ar in all groups, but the ocular movement scores at 8 min were significantl y lower in the group which received hyaluronidase 150 IU ml(-1) than in the group not given hyaluronidase (P <0.03). There were no differences between groups in the incidence of minor complications. A high concentration of hy aluronidase resulted in a statistically significantly lower ocular movement score at 8 min; the clinical relevance of this finding is uncertain.