AIM: To assess the efficacy and adverse reactions of two concentrations of diluted botulism toxin A(BTX-A)for blepharospasm.

METHODS: Totally 220 patients(440 eyes)confirmedas blepharospasm in our department(from January 2013 to January 2015), were divided randomly into two groups: 110 in high concentration group and 110 in low concentration group. The two groups were given local injections with 25 U/mL or 40 U/mL concentration of botulism toxin type A to the upper and lower eyelids orbicular muscle, corrugator, reducing eyebrow muscle and procerus respectively. We observed dosage of two groups, the treatment effect, the duration of the effect and the incidence of adverse reactions.

RESULTS: The high concentration group was given the BTX-A with 48.33±4.02U,the low concentration group was given the BTX-A with 28.51±3.42U,the differences were statistically significant(P<0.05). The differences of post-operative evaluation of curative effect, onset time and duration of the effect between the groups were not statistically significant(P >0.05). Sixteen cases had ptosis in different levels in the high concentration group, and 2 in the low concentration group, the differences were statistically significant(P<0.01). There were no serious complications such as intoxication, drug allergy in both groups. Ptosis relieved after using naphcon-A and disappeared in 2-3 wk.

CONCLUSION: The efficacy of local injection with two concentrations of diluted botulinum toxin A for blepharospasm was positive. Considering the high incidence of ptosis in high concentration group, we recommended the 25U/mL botulism toxin A for blepharospasm.