Quantitative Evaluation of Microdistortions in Bowman's Layer and Corneal Deformation after Small Incision Lenticule Extraction

PURPOSE: To quantitatively evaluate microdistortions in Bowman's layer and change in corneal stiffness after small incision lenticule extraction (SMILE). METHODS: This was a prospective, longitudinal, and interventional study. Thirty eyes of 30 patients were screened preoperatively and underwent SMILE for treatment of myopia with astigmatism. Visual acuity, refraction, optical coherence tomography (OCT; Bioptigen, Inc., Morrisville, NC) imaging of the layer and air-puff applanation (Corvis-ST, OCULUS Optikgeräte Gmbh, Germany) was performed before and after surgery (1 day, 1 week, and 1 month). The Bowman's Roughness Index (BRI) was defined as the enclosed area between the actual and an ideal smooth layer to quantify the microdistortions. A viscoelastic model was used to quantify the change in corneal stiffness using applanation. RESULTS: = 0.61). CONCLUSIONS: BRI correlated positively the magnitude of refractive error. However, decrease in corneal stiffness, assessed by air-puff applanation, may not be related to microdistortions after SMILE. TRANSLATIONAL RELEVANCE: An objective method of quantification of Bowman's layer microdistortions using OCT was developed to monitor corneal wound healing and improve lenticule extraction methods.