Motwani M, et al. - In this retrospective study, the author analyzes a biomechanical corneal change related to corneal flap creation in certain patients leading to an irregular ablation pattern and an inaccurate refractive outcome. Using the LYRA Protocol, consecutive eyes treated with primary LASIK Contoura were included. The WaveLight EX500 excimer laser was used for all LASIK procedures. There are six representative cases showing biomechanical change, outcomes, and treatment. All patients showed an elliptical, irregular ablation pattern on post-operative topography, lateralized the thinnest point of the cornea relative to the corneal apex on Pentacam pachymetry maps, and irregular corneal epithelial thickening at the periphery of the elliptical ablation. A biomechanical shift can occur during flap creation in certain types of corneas during LASIK flap creation and subsequent treatment with topographic-guided ablation leading to an irregular ablation and suboptimal refractive results.