Efficacy at early stage after FS-LASIK with accelerated corneal collagen cross-linking

AIM:To evaluate the safety and efficacy at early stage after femtosecond laser-assisted excimer laser <i>in situ</i> keratomileusis(FS-LASIK)combined with collagen cross-linking. <p>METHODS: Totally 30 myopia patients(60 eyes)received FS-LASIK combined with collagen cross-linking from July 2016 to August 2017 in our hospital were tested the uncorrected visual acuity(UCVA), Ks, Kf, surface regular index(SRI), surface asymmetry index(SAI)by corneal topography(TMS)preoperatively, 1, 3mo after operation. The corneal compensated intraocular pressure(IOPcc), Goldmann correlated IOP value(IOPg), corneal resistance factor(CRF), corneal hysteresis(CH)tested by ocular response analyzer(ORA)were also observed. Ziemer Galilei Dual Scheimpflug Analyzer detected the anterior diopter and the corneal thickness. Endothelial cell density were examined.<p>RESULTS:The postoperative UCVA remained beyond 0.8 including 26 eyes(43%)of 1d, 55 eyes(92%)of 1mo, 50 eyes(83%)of 3mo. IOPcc, IOPg, CRF, CH at postoperative 1mo significantly decreased comparing with preoperative(<i>P</i><0.01). IOPcc, IOPg, CRF, CH at postoperative 3mo did not change significantly comparing with 1mo(<i>P</i>>0.05). The corneal topographic map parameters of Ks and Kf significantly decreased at postoperative 1mo(<i>P</i><0.01), while SRI and SAI increased significantly(<i>P</i><0.01)on comparison of 1mo and preoperative. Ks of postoperative 3mo was significantly higher than that of 1mo(<i>P</i><0.05), while Kf did not change significantly(<i>P</i>>0.05). There was a significant decrease in SRI and SAI between 3mo and 1mo after operation(<i>P</i><0.05). In Galileo analysis on comparison of 3mo and 1mo, Sim Ks, Sim Kf had 0.94D, 0.95D growth and the front and back surface value of Kf increased more at 3mo postoperative(<i>P</i><0.01), while Ks was no significant difference(<i>P</i>>0.05). There was no statistically significant difference in corneal thickness between the central point and the thinnest point(<i>P</i>>0.05). There was no significant endothelial cell loss throughout follow up(3059.95±247.87/mm² <i>vs</i> 3052.87±267.71/mm²; <i>t</i>=0.279, <i>P</i>>0.05). <p>CONCLUSION: Refractive corneal surgery combined with collagen cross linking for high degree, thin cornea, uneven thickness of the cornea, topographic anomalies except for the patients with keratoconus, play a role in stabilizing corneal shape and increasing corneal biomechanics early