Effect of femtosmile for high myopes on corneal biomechanics and tonometry using the Corneal Visualization Scheimpflug Technology

Abstract

Background The Corneal Visualization Scheimpflug Technology (Corvis ST) is a noncontact tonometer that enables quantitative assessment of dynamic corneal deformation. This study aimed to evaluate the biomechanical effects of Femtosecond Small-Incision Lenticule Extraction in myopic eyes using Corvis ST and to determine its impact on intraocular pressure (IOP) measurements by Goldmann Applanation Tonometry. Patients and methods This prospective randomized study included 60 eyes of 60 patients (≥18 years) with stable myopia up to −8.00 D and astigmatism less than −4.00 D. Pre- and postoperative measurements (1, 6, and 12 months) were performed using Corvis ST and Goldmann Applanation Tonometry. Results Significant changes were noted in corneal biomechanical parameters 1 month postoperatively ( P <0.05), including deformation amplitude and stiffness parameter, indicating early biomechanical alterations. No significant differences were observed between 6- and 12-month visits, suggesting biomechanical stabilization. At 1 month, biomechanically corrected IOP (bIOP) was significantly higher than Goldmann IOP ( P <0.05) and remained stable thereafter. Conclusion Femtosecond small-incision lenticule extraction causes early corneal biomechanical changes that stabilize after 1 month, reflecting rapid biomechanical recovery. Corvis ST offers a reliable method for assessing these changes and postoperative IOP measurements.