Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Eye Research Center, Binaafarin Clinic, Tehran, Iran.
Eur J Ophthalmol. 2021 Jul;31(4):1577-1583. doi: 10.1177/1120672120944798. Epub 2020 Jul 25.
A 6-month evaluation of the topographic and biomechanical changes induced by corneal collagen cross-linking (CXL) in keratoconic eyes using Pentacam and Corvis ST.
Longitudinal prospective case series.
In this study, 67 eyes of 67 patients with progressive keratoconus (KCN) treated with "Epithelium-off" CXL were evaluated. Patients with stages 1 or 2 of KCN and a corneal thickness of at least 400 μm at the thinnest point were included. Standard ophthalmologic examinations were carried out for all patients. The topographic and biomechanical measurements of the cornea were obtained by Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) preoperatively and 6-month postoperatively.
The mean age of the participants was 21.68 ± 4.23 years. There was significant difference in mean spherical equivalent (SE) before and 6 months after CXL. Uncorrected and best corrected visual acuity improved postoperatively, although not statistically significant. The mean and maximum keratometry showed a significant decrease 6 months after CXL (0.93 ± 0.38 D and 1.43 ± 0.62 D, respectively < 0.001). Among Corvis ST parameters, first applanation length and velocity (AL1 and AV1) showed statistically significant changes. The radius at highest concavity changed significantly (0.13 ± 0.37 mm mean increase after CXL; < 0.001). A significant increase was observed in stiffness parameter A1 (SP-A1; < 0.001) and significant decreases were noted in integrated radius (IR) and deformation amplitude ratio (DAR; < 0.001).
Analyzing biomechanical changes after corneal cross-linking can provide basis for efficient KCN treatment. Corvis ST parameters demonstrated changes in corneal biomechanical characteristics indicative of stiffing after CXL.
使用 Pentacam 和 Corvis ST 评估角膜胶原交联 (CXL) 治疗后角膜地形图和生物力学在圆锥角膜眼中的 6 个月变化。
纵向前瞻性病例系列。
本研究纳入了 67 例进展性圆锥角膜（KCN）患者的 67 只眼，这些患者接受了“上皮下”CXL 治疗。纳入标准为 KCN 1 或 2 期，且最薄点角膜厚度至少为 400μm。所有患者均进行了标准眼科检查。在术前和术后 6 个月，使用 Pentacam（德国 Oculus Optikgeräte GmbH）和 Corvis ST（德国 Oculus Optikgeräte GmbH）获取角膜的地形图和生物力学测量值。
参与者的平均年龄为 21.68±4.23 岁。CXL 前后平均等效球镜（SE）差异有统计学意义。术后未矫正和最佳矫正视力均有所提高，但无统计学意义。6 个月后平均和最大角膜曲率值明显下降（分别为 0.93±0.38 D 和 1.43±0.62 D，均<0.001）。Corvis ST 参数中，首次压平长度和速度（AL1 和 AV1）有统计学意义的变化。最高凹陷处半径明显改变（CXL 后平均增加 0.13±0.37mm；<0.001）。弹性参数 A1（SP-A1）显著增加（<0.001），整合半径（IR）和变形幅度比（DAR）显著降低（均<0.001）。
分析角膜交联后生物力学变化可为高效治疗圆锥角膜提供依据。Corvis ST 参数显示角膜生物力学特性发生变化，提示交联后角膜变硬。
