Tear osmolarity, dry eye syndrome, blepharospasm and botulinum neurotoxin

To assess the severity of dry eye disease in patients with blepharospasm (BEB) before (control) and after injection of botulinum neurotoxin A (BoNT/A). Cross-sectional study. Patients with clinically diagnosed BEB and no known history of dry eye syndrome prior to the onset of the disease, before (controls) or after injection with one of the three available types of BoNT/A: onabotulinumtoxinA (Botox®; Allergan, Irvine, CA, USA), abobotulinumtoxinA (Dysport®; Beaufour Ipsen Pharma SAS, Paris, France) or incobotulinumtoxinA (Xeomin®; Merz Pharma GmbH, Frankfurt, Germany) every 3 months. Tear osmolarity and Schirmer's I-test were measured at the first visit for non-treated BEB patients as controls and 3 months after BoNT/A injection. The study consisted of 101 BEB patients (86 females, 15 males) with a mean age of 67 years (range 30–86 years). Seventeen patients were untreated, 26 treated with onabotulinumtoxinA, 23 treated with abobotulinumtoxinA and 35 treated with incobotulinumtoxinA. Post-injection mean tear osmolarity was not significantly higher among patients treated with onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA (P=0.65, P=0.92, and P=0.15, respectively), compared to controls, remaining less than 308 mosm/mL. Mean Schirmer's I-test results remained under 5mm and did not vary between the four groups. The results clearly demonstrate that reduced tear secretion appears to be present in BEB patients even prior to treatment. This decreased lacrimal secretion was not correlated with hyperosmolarity. Clinicians should proactively treat dry eye syndrome in conjunction with management of the blepharospasm. Évaluer la sévérité de la sécheresse oculaire chez les patients atteints de blépharospasme, et si celle-ci s’aggrave lors de l’injection de toxine botulique. Étude transversale. Analyse des patients atteints de blépharospasme essentiel, sans antécédents, connus de syndrome sec oculaire, précédant l’apparition du blépharospasme, avant (patients témoins) et après traitement par injection de neurotoxine botulique A (BoNT/A), injection avec les trois types de BoNT/A disponibles : onabotulinumtoxinA (Botox® ; Allergan, Irvine, CA, USA), abobotulinumtoxinA (Dysport® ; Beaufour Ipsen Pharma SAS, Paris, France) ou incobotulinumtoxinA (Xeomin® ; Merz Pharma GmbH, Frankfurt, Allemagne) tous les 3 mois. L’osmolarité lacrymale et le test de Schirmer I ont été réalisés à la première consultation pour les patients atteints de blépharospasme, dits patie