Transl Vis Sci Technol. 2024 Nov 4;13(11):29. doi: 10.1167/tvst.13.11.29.
ABSTRACT
PURPOSE: The purpose of this study was to compare the actual corneal consumption and subsequent corneal biomechanical changes after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) in eyes with high myopic astigmatism.
METHODS: In this prospective, randomized study on high myopic astigmatic eyes, 74 patients with similar refractive error received SMILE in one eye and FS-LASIK in the contralateral eye were enrolled. The central stromal reduction was calculated by preoperative and postoperative central stromal thickness (CST) measurements by the RTVue optical coherence tomography (OCT). Changes in corneal volume (CV) were evaluated by Pentacam HR. The corneal biomechanical parameters were measured with Corvis ST II.
RESULTS: At the 6-month postoperative visit, the mean actual central stromal reduction achieved with SMILE was significantly less than that achieved with FS-LASIK (108.23 ± 16.52 µm vs. 122.66 ± 27.33 µm, P < 0.001). The residual central corneal thickness (CCT), CV 3 mm, CV 5 mm, and stiffness parameter at first applanation (SP-A1) after SMILE were all greater than those of FS-LASIK (all P < 0.05). Moreover, the residual CCT, CV 3 mm, and CV 5 mm were positively correlated with Ambrósio relational thickness through the horizontal meridian (ARTh) and SP-A1, while negatively correlated with the integrated radius (IR) and deformation amplitude (DA) ratio 2.0 mm in both the SMILE and FS-LASIK groups (all P < 0.05).
CONCLUSIONS: In patients with high myopia astigmatism, SMILE required fewer corneal stromal tissues and thus better corneal biomechanics than FS-LASIK when correcting a similar spherical equivalent refraction. Moreover, SP-A1 may be a more sensitive indicator for evaluating corneal biomechanical changes after refractive surgeries.
TRANSLATIONAL RELEVANCE: Fewer corneal stromal consumption with SMILE surgery may contribute to better corneal biomechanics in high myopic astigmatic eyes in comparison to FS-LASIK, which could provide reliable evidence for the appropriate choice of refractive surgery for patients with high myopic astigmatism.
PMID:39576656 | DOI:10.1167/tvst.13.11.29