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

PURPOSE: 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.

SETTING: Federal University of São Paulo, São Paulo, Brazil.

DESIGN: Prospective interventional case series.

METHODS: 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 15 days and 2, 3, and 4 months.

RESULTS: The 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).

CONCLUSION: The Placido system was more sensitive in detecting a temporary reduction in corneal curvature after eyelid-spasm treatment.

FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.