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  • Botox for Blepharospasm: Role of Injection Site

    By Lynda Seminara
    Selected by Richard K. Parrish II, MD
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    Journal Highlights

    American Journal of Ophthalmology, December 2021

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    Although the cause of benign essential blepharospasm is unknown and there is no cure, some symptoms may be alleviated with periocular injection of botulinum toxin type A (BTX-A). Previous studies have found that the efficacy of BTX-A varies according to whether it is delivered by preseptal or pretarsal injection. Sanguandikul et al. set out to evaluate the rate of compli­cations by injection site. They found that although lagophthalmos was more common after pretarsal injection, there was little difference in the degree of lagophthalmos between the preseptal or pretarsal groups.

    For this double-masked comparison study, the authors recruited 24 adults (mean age, 63.6 years) with blephar­ospasm from a hospital in Bangkok, Thailand. Each patient received a preseptal injection of BTX-A into one eye (chosen randomly) and a pretarsal injection into the fellow eye. At baseline and one and three months postinjec­tion, the patients were interviewed and examined to assess tearing, lagophthalmos, ptosis, diplopia, margin-to-reflex distance, ocular motility, and presence of ectropion and entropion.

    In addition, tear film breakup time was determined, Schirmer testing was performed, and the ocular surface was stained (Oxford scheme). The Jankovic rating scale was used to grade the fre­quency and severity of blepharospasm. The main outcome measurement was the incidence of complications follow­ing the injections.

    Before injection, no patient in either group exhibited lagophthalmos, ectro­pion, entropion, or impaired ocular motility. One month after BTX-A injection, one patient was lost to fol­low-up. For the remaining 23 patients, the rate of self-reported lagophthalmos was higher in pretarsal eyes (n = 12; 52.17%) than in preseptal eyes (n = 7; 30.43%) (p = .024). At this time, the estimated degree of lagophthalmos also was significantly higher for the pretarsal group (0.59 mm vs. 0.26 mm; Bonferroni-corrected p = .001). There were no significant differences between the groups in complications related to blepharospasm.

    The original article can be found here.