Chen Hao, Wang Ziqian, Li Kunke, Wang Yiran, Li Xin, Du Lan, Lin Meimin, Savini Giacomo, Wang Qinmei, Yu Ayong, Chen Sisi
School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.
Shenzhen Eye Hospital, Shenzhen Key Ophthalmic Laboratory, Jinan University, Shenzhen, China.
Front Med (Lausanne). 2022 May 19;9:907334. doi: 10.3389/fmed.2022.907334. eCollection 2022.
To compare the predicted ablation depth (AD) with the postoperatively measured corneal ablation depth (postop-AD) at central, paracentral, and midperipheral locations using two rotating Scheimpflug analyzers and a Fourier-domain optical coherence tomographer in eyes that underwent femtosecond laser-assisted LASIK (FS-LASIK).
The values of corneal thickness were measured preoperatively and postoperatively at one and three months. The difference between preoperative and postoperative was defined as postop-AD. Measurements were performed at the corneal vertex and mid-peripheral area. The mid-peripheral corneal thickness was measured at the superior, inferior, nasal, and temporal locations at a distance of 1.0 or 2.5 mm from the corneal vertex. The predicted AD was calculated by ORK-CAM software (Schwind eye tech-solutions GmbH, Kleinostheim, Germany), and the difference between the predicted AD and postop-AD was defined as Δ-AD. Paired test analysis was employed to evaluate the differences, agreement was assessed by the Bland-Altman method.
Forty-two eyes of 42 patients were investigated. At one month, the predicted AD in the central and paracentral areas was underestimated by the Pentacam HR (Oculus, Wetzlar, Germany), Sirius (Costruzione Strumenti Oftalmici, Florence, Italy) and RTVue OCT (Optovue Inc., Freemont, CA, United States), whereas Δ-AD was negative as established by all devices and predominantly statistically significant. The Δ-AD values approximated zero at three months. The mean difference of Δ-AD at three months at the corneal vertex was 0.67 ± 9.39 mm, -7.92 ± 9.05 mm and -1.36 ± 8.31 mm, respectively. The mid-peripheral measurements had positive values at one month and even more highly positive at three months (with statistically significant differences in most of the cases). The agreement between the predicted and postop-AD was moderate with all devices, but slightly better with RTVue.
The predicted AD seems to be underestimated in the central and paracentral corneal area and overestimated in the mid-periphery.
The study could help to partly explain and prevent the refractive errors after FS-LASIK.
在接受飞秒激光辅助准分子原位角膜磨镶术（FS-LASIK）的眼中，使用两台旋转式Scheimpflug分析仪和一台傅里叶域光学相干断层扫描仪，比较中央、旁中央和中周边区域的预测消融深度（AD）与术后测量的角膜消融深度（术后AD）。
在术前以及术后1个月和3个月测量角膜厚度值。术前与术后的差值定义为术后AD。测量在角膜顶点和中周边区域进行。中周边角膜厚度在距角膜顶点1.0或2.5mm处的上方、下方、鼻侧和颞侧位置测量。预测AD由ORK-CAM软件（德国克莱诺施泰姆的Schwind眼科技术解决方案有限公司）计算得出，预测AD与术后AD的差值定义为Δ-AD。采用配对检验分析评估差异，通过Bland-Altman方法评估一致性。
对42例患者的42只眼进行了研究。在术后1个月时，德国韦茨拉尔的Oculus公司的Pentacam HR、意大利佛罗伦萨的Costruzione Strumenti Oftalmici公司的Sirius以及美国加利福尼亚州弗里蒙特的Optovue公司的RTVue OCT均低估了中央和旁中央区域的预测AD，而所有设备得出的Δ-AD均为负值，且大多具有统计学意义。在术后3个月时，Δ-AD值接近零。术后3个月时，角膜顶点处的Δ-AD平均差值分别为0.67±9.39mm、-7.92±9.05mm和-1.36±8.31mm。中周边测量值在术后1个月为正值，在术后3个月时正值更高（大多数情况下具有统计学显著差异）。所有设备预测AD与术后AD之间的一致性为中等，但RTVue的一致性略好。
预测AD在中央和旁中央角膜区域似乎被低估，而在中周边区域被高估。
该研究有助于部分解释和预防FS-LASIK术后的屈光不正。
