Corneal biomechanical properties in myopic LASIK.

Purpose Describe and quantify the effect of myopic LASIK on corneal biomechanics considering the preoperative hysteresis Methods In 126 eyes with myopia and myopic astigmatism the Ocular Response Analyzer (ORA) was used to measure corneal hysteresis (CH), corneal resistance factor (CRF), Goldman‐correlated intraocular pressure (IOPg), and corneal‐compensated IOP (IOPcc) before and 3 months after LASIK. We divided the sample into three groups based on the values of CH (mmHg) preoperative: G1 (30 eyes) CH 7.5‐9.5, G2 (66 eyes) 9.5‐11.5, G3 (30 eyes) >11.5. Results After LASIK, there was a reduction in mean CH (ΔCH; G1:0.98 G2:1.51 G3: 1.81), CRF (ΔCRF; G1:2.35 G2:2.46 G3:2.83), IOPcc (ΔIOPcc; G1: 3.26 G2:1.74 G3: 1.75) and IOPg (ΔIOPg; G1: 5.01 G2:3.92 G3: 4.31) in three groups. However, there was no statistically significant difference between the groups in the percentage change of CH (G1: 13% G2: 14.6% G3: 15%) and CRF (G1: 25% G2: 23% G3: 24%). While the percentage decrease in IOPcc (G1: 18% G2: 10.5% G3: 11.5%) and IOPg (G1: 31% G2: 25% G3: 27%) was statistically different. Was find a significant correlation between ΔCH and ΔCRF with microns of ablation (r =‐ 0.406, r =‐ 0.616) and spherical equivalent (r = 0.405, r =‐ 0.599). Conclusion LASIK surgery decreases the corneal hysteresis and corneal resistance factor. The percentage decline of corneal hysteresis and corneal resistance factor after LASIK surgery was no different between the three groups based on the preoperative hysteresis. Although there is a correlation between variations of the CH and CRF, with microns of ablation and the refractive error corrected. [ABSTRACT FROM AUTHOR]