Fernández Joaquín, Rodríguez-Vallejo Manuel, Martínez Javier, Tauste Ana, Piñero David P
J Refract Surg. 2016 Dec 1;32(12):821-828. doi: 10.3928/1081597X-20160816-02.
To evaluate the corneal biomechanical changes due to small incision lenticule extraction (SMILE) measured by Scheimpflug-based dynamic tonometry and to assess the impact of the corneal thickness.
Sixty-eight patients measured with the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) preoperatively and 1 month after SMILE were included in this retrospective observational study. Patients were divided into three groups depending on the preoperative spherical equivalent: low from -1.00 to -3.00 diopters (D), medium from -3.25 to -5.00 D, and high from -5.25 to -7.25 D. Changes in Corvis ST parameters due to the surgery were analyzed and new indexes for correcting the impact of corneal thickness were proposed.
First and second applanation times changed after SMILE (P < .0001) but no differences were found in the comparison between these relative changes (P = .31). First applanation time was correlated with central corneal thickness (r = 0.368, P = .002) but not second applanation time (r = -0.149, P = .23). The change in first applanation time due to SMILE was different among myopic groups (P = .007) but equal when a new index that considers the removed central corneal thickness was used for comparison (P = .31). Deformation amplitude was also increased after SMILE (P < .0001), but after subtracting the removed corneal thickness from the postoperative deformation amplitude the result was equal to the preoperative deformation amplitude (P = .26).
SMILE produces significant changes in the Corvis ST parameters of time and deformation amplitude, but these changes are mainly explained by the confounding variable of corneal thickness. [J Refract Surg. 2016;32(12):821-828.].
通过基于Scheimpflug原理的动态眼压测量法评估小切口透镜切除术（SMILE）引起的角膜生物力学变化，并评估角膜厚度的影响。
本回顾性观察研究纳入了68例术前及SMILE术后1个月使用Corvis ST（德国韦茨拉尔市Oculus Optikgeräte GmbH公司）测量的患者。根据术前等效球镜度数将患者分为三组：低度数组为-1.00至-3.00屈光度（D），中度组为-3.25至-5.00 D，高度组为-5.25至-7.25 D。分析手术引起的Corvis ST参数变化，并提出校正角膜厚度影响的新指标。
SMILE术后首次和第二次压平时间发生变化（P <.0001），但这些相对变化之间的比较未发现差异（P =.31）。首次压平时间与中央角膜厚度相关（r = 0.368，P =.002），但与第二次压平时间无关（r = -0.149，P =.23）。SMILE引起的首次压平时间变化在近视组之间存在差异（P =.007），但当使用考虑切除的中央角膜厚度的新指标进行比较时则相等（P =.31）。SMILE术后变形幅度也增加（P <.0001），但从术后变形幅度中减去切除的角膜厚度后，结果与术前变形幅度相等（P =.26）。
SMILE会使Corvis ST的时间和变形幅度参数发生显著变化，但这些变化主要由角膜厚度的混杂变量解释。[《屈光手术杂志》。2016；32（12）：821 - 828。]
