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To assess the regional changes in corneal shape after femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) in patients with different myopia extents. Eye Hospital, Wenzhou Medical University, Wenzhou, China. Retrospective case series. A retrospective study of myopic eyes treated with FS-LASIK was conducted to assess the shape changes within different corneal regions after surgery. Corneal curvature was measured in the central region (0 mm to 3.0 mm diameter), pericentral region (3.0 mm to 6.0 mm diameter) and peripheral region (6.0 mm to 9.0 mm diameter) preoperatively and from 1 week to 6 months postoperatively. The study comprised 608 myopic eyes. During the 6-month follow-up, the anterior cornea became steeper in the central and pericentral regions, but flatter in the peripheral region (P <.01), representing a partial, gradual, yet significant reversal of the immediate change in corneal shape after laser ablation. In contrast, the posterior surface experienced significantly less change than the anterior surface, with the cornea becoming slightly flatter (P <.01) in the central region at 1 week postoperatively, and steeper elsewhere (P <.05), and then remaining stable during the rest of the follow-up. On the other hand, the anterior astigmatism had significant decreases in the central region (P <.01) and slight increases in the peripheral region (P <.01) 1 week postoperatively, and that remained stable over the follow-up period. In contrast, there were little or non-significant changes in the posterior astigmatism throughout the follow-up (P >.05). Postoperative corneal shape changes were different in different regions. There were shape changes in individual corneal regions during the 6-month follow-up period that represented reverse trends; however, the changes were much smaller than the short-term changes observed 1 week after surgery. [ABSTRACT FROM AUTHOR]

Purpose: To test the performance of 4 tonometers in estimating intraocular pressure (IOP) after 3 forms of refractive surgery. Setting: Eye Hospital, Wenzhou Medical University, China. Design: Prospective case series. Methods: Patients matched for preoperative age, corneal thickness, and myopic correction enrolled for femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), small-incision lenticule extraction (SMILE), or transepithelial photorefractive keratectomy (tPRK) were included in the study. For each patient, 4 measurements of IOP were obtained preoperatively and 3 months postoperatively, using the Goldmann applanation tonometer (GAT-IOP), the Dynamic Contour Tonometer (DCT-IOP), corneal-compensated IOP (IOPcc) from the Ocular Response Analyzer, and biomechanically corrected IOP (bIOP) from the Corvis ST. Overall corneal stiffness was also estimated based on the stiffness parameter (SP-A1) provided by the Corvis ST. Results: The study included 144 eyes of 144 patients. Among the 3 procedures, the smallest variances between preoperative and postoperative IOP estimates and SP-A1 values were observed with the tPRK, followed by SMILE and FS-LASIK. In the tPRK group, no significant differences were observed in both bIOP (-0.18 +/- 1.63 mm Hg) and DCT-IOP (-.64 +/- 2.34 mm Hg), whereas they were larger and significant in GAT-IOP (-1.78 +/- 2.29 mm Hg) and IOPcc (-2.77 +/- 1.84 mm Hg). In FS-LASIK and SMILE groups, although there were similar significant reductions in IOP postoperatively, these reductions were still lower in bIOP and DCT-IOP than those in GAT-IOP and IOPcc. Conclusions: The bIOP and DCT-IOP were the least affected IOP estimates between the 3 refractive surgery procedures considered. It was evident that tPRK produced significantly smaller reductions in IOP readings than did FS-LASIK and SMILE. [ABSTRACT FROM AUTHOR]