Impact of botulinum toxin-A on corneal curvature assessed with Scheimpflug and Placido systems

Abstract

To evaluate the effect of eyelid spasm treatment with botulinum toxin-A (BTX-A) on corneal curvature assessed with Scheimpflug (Pentacam) and Placido (Atlas) systems. Federal University of São Paulo, São Paulo, Brazil. Prospective interventional case series. Patients with hemifacial spasm were evaluated. Steep keratometry (K) and corneal astigmatism (magnitudes and treatment-induced astigmatism) obtained with the Placido and Scheimpflug systems were evaluated before BTX-A application and after 15days and 2, 3, and 4months. The study evaluated 48 eyes (24 affected and 24 normal contralateral eyes) of 24patients. The mean steep K and astigmatism values obtained with the Placido system on the affected side beforetreatment were 46.91 diopters (D)±3.57 (SD) and 2.63±2.46 D, respectively. A significant decrease in steep K (45.14±1.20 D) and astigmatism (1.01±0.58 D) was observed 2months (P=.003 and P=.0004, respectively) and 3months (45.64±1.77 D and 1.36±1.31 D, respectively) (P=.03 and P=.01, respectively) after treatment. The Scheimpflug system did not show significant changes in steep K measurements during the 4-month period. The mean astigmatism in the affected eye before treatment was 1.27±0.88 D. A significant reduction was observed at 15days (1.16±1.16 D) and at 4months (0.91±0.59 D) (P=.02 and P=.03, respectively). The Placido system was more sensitive in detecting a temporary reduction in corneal curvature after eyelid-spasm treatment. None of the authors has a financial or proprietary interest in any material ormethod mentioned.