Tear production and drainage after botulinum toxin A injection in patients with essential blepharospasm

To evaluate the clinical manifestations of tear production, distribution and drainage in the essential blepharospasm patients, and to analyse the changes after botulinum toxin A injection in these patients.

This prospective study was performed in 23 patients with essential blepharospasm treated with Botulinum neurotoxin A (BoNT-A; Dysport, Ipsen Biopharm, UK) from November 2010 to February 2011. Ocular examinations, including frequency and severity of blepharospasm, tear break up time (BUT), Schirmer's test, lower lid tear meniscus height (TMH) measured by optical coherence tomography (OCT, rtvue software version 3.5; Optovue Inc., Fremont, CA, USA), and dacryoscintigraphy using 99m technetium pertechnetate, were performed before and 2 weeks after BoNT-A injection. We asked all patients about changes in the dry eye symptom score, before and after treatment. Results were analysed with independent t-test using spss software version 12.0 for Windows XP, (SPSS Inc., Chicago, IL, USA).

Botulinum neurotoxin A treatment relieved blepharospasm in all patients. Mean injection dose was 38 ± 5.6 units. After injection, mean tear BUT was significantly increased from 4.7 ± 4.9 to 6.6 ± 1.6 seconds (p = 0.001) Lower TMH increased in all three points and most notably at the lateral point (p = 0.05). On dacryoscintigraphy, tear drainage velocity was not affected by BoNT-A treatment. But Tc-99m 50% clearance time in interpalpebral fissure significantly increased from 1564 to 2220 seconds on the time activity curve (p = 0.027). Subjective dry eye symptoms also improved in 16 patients (70%) after injection.

Tear film stability and TMH increased, but tear drainage velocity was not affected by BoNT-A treatment. Overall Tc-99m 50% clearance time in interpalpebral fissure significantly increased, and tear storage from mild lateral lower eyelid laxity increased after BoNT-A injection. Botulinum neurotoxin A injection was also effective for combined dry eye symptom in the essential blepharospasm patients.