Complications of Preseptal Versus Pretarsal Botulinum Toxin Injection in Benign Essential Blepharospasm: A Randomized Controlled Trial.

PURPOSE: The purpose of this study was to compare ocular complications and efficacy of preseptal (PST) versus those of pretarsal (PTS) botulinum toxin type A (BoNT-A) therapy in cases of benign essential blepharospasm (BEB).

DESIGN

Randomized clinical trial.

METHODS

Setting

university hospital.

PATIENTS: 24 participants with BEB were enrolled from August 2019 to June 2020. All patients and the outcome evaluator were masked to the injection allocation.

INTERVENTIONS: for each participant, 1 eye was randomized to receive PST BoNT-A injection, and the fellow eye received PTS BoNT-A injection of the same amount from a single investigator. At baseline, 1, and 3 months after the injection, we collected the symptoms of tearing, lagophthalmos, ptosis, and diplopia and measured margin-to-reflex distance (MRD) 1 and 2 (mm), degree of lagophthalmos (mm), presence of ectropion, entropion, limitation of ocular motility, tear film breakup time (second), Schirmer's test (mm) , ocular surface staining scores (Oxford's scheme), and Jankovic rating scale of both eyes separately. Main outcome measurements were complications of the injection.

RESULTS

There were statistically significant higher rates of self-reported lagophthalmos in PTS (n = 12; 52.17%) than in PST (n = 7; 30.43%) BoNT-A injections (P = .024) and significantly higher estimated measurements of lagophthalmos in PTS (0.59 mm; 95% confidence interval [CI]: 0.44-0.72) than in PST (0.26 mm; 95% CI: 0.12-0.40) injection at 1 month using an interaction model (Bonferroni-corrected P = .001). No significant differences in the efficacy and other complication outcomes between the injection locations were observed.

CONCLUSIONS

PTS BoNT-A injection had a higher rate of lagophthalmos than PST BoNT-A injection for BEB.