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

Abstract

ABSTRACT.Purpose: 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. Methods: 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). Results: 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. Conclusion: 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.

Botulinum toxin and blink rate in patients with blepharospasm and increased blinking

“…This mechanism may therefore promote the overactivation of the spontaneous blink generator. In line with our hypothesis, it has been recently demonstrated that BoNT injected into the OO muscles—by reducing clearance time in the interpalpebral fissures—increases tear film stability and tear storage in the lower eyelid 42. In a previous study, BoNT also reduced the lacrimal pump exerted by the OO muscle 43.…”

Corneal and Tear Film Changes After Botulinum Toxin-A in Blepharospasm or Hemifacial Spasm

“…It is also well known that the effect of botulinum toxin is temporary and repeated applications are required. 1,[4][5][6]8,9 In this study, we found that blepharospasm and hemifacial spasm severity improved significantly from pretreatment to 3 weeks after the BTX-A injection. However, by the third month, spasm severity returned to pretreatment levels.…”

“…[7][8][9]19 Paradoxically, BTX-A has also been suggested for treating dry eye syndrome. [8][9][10]20,21 In these reports, BTX-A was injected into the periorbital area including the medial part of the orbicularis oculi muscle when treating existing dry eye syndrome. BTX-A injection also leads to reduced lacrimal drainage after treatment.…”

“…6 Many patients with blepharospasm also have dry eye disease, in varying degrees. 7 Park et al 8 reported that the production, distribution, and drainage of tears were affected in patients with blepharospasm. In addition, neurotoxin injection improved dry eye symptoms in patients with blepharospasm, and this treatment has been suggested for dry eyes.…”

“…In addition, neurotoxin injection improved dry eye symptoms in patients with blepharospasm, and this treatment has been suggested for dry eyes. [8][9][10] It is well known that eyelid pressure has a direct effect on the corneal shape and causes astigmatism. 11,12 Moon et al 13 reported corneal astigmatism changes in patients with blepharospasm or hemifacial spasm after the injection of botulinum toxin.…”