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

PurposeTo evaluate the effect of eyelid spasm treatment with botulinum toxin-A (BTX-A) on corneal curvature assessed with Scheimpflug (Pentacam) and Placido (Atlas) systems.SettingFederal University of São Paulo, São Paulo, Brazil.DesignProspective interventional case series.MethodsPatients 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 15 days and 2, 3, and 4 months.ResultsThe study evaluated 48 eyes (24 affected and 24 normal contralateral eyes) of 24 patients. The mean steep K and astigmatism values obtained with the Placido system on the affected side before treatment 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 2 months (P = .003 and P = .0004, respectively) and 3 months (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 15 days (1.16 ± 1.16 D) and at 4 months (0.91 ± 0.59 D) (P = .02 and P = .03, respectively).ConclusionThe Placido system was more sensitive in detecting a temporary reduction in corneal curvature after eyelid-spasm treatment.Financial DisclosureNone of the authors has a financial or proprietary interest in any material or method mentioned.