Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China; NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, China; Shanghai Research Center of Ophthalmology and Optometry, Shanghai, 200031, China; Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, 200031, China.
College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, China.
Exp Eye Res. 2023 Feb;227:109363. doi: 10.1016/j.exer.2022.109363. Epub 2022 Dec 28.
Corneal cross-linking (CXL) has been proved efficiency for treating progressive keratoconus and other corneal ectasia diseases by stabilizing corneal geometry and biomechanics. However, the necessity of repeated CXL treatment in patients is unknown. This study aimed to investigate corneal biomechanical stiffness and change in corneal histopathological characteristics after repeated accelerated CXL (A-CXL) in cat eyes. A-CXL was performed with 0.1% riboflavin applied for 10 min, followed by ultraviolet A irradiation at 30 mW/cm for 3 min at 365 nm in 15 domestic cats. Corneas (n = 30) were divided into three groups: one-time accelerated corneal cross-linking (A-CXL1 group), repeated accelerated corneal cross-linking (A-CXL2 group), and an untreated control group. In A-CXL2 group, A-CXL was repeated at 1-month intervals. In vivo ocular examinations were performed pre- and postoperatively. Biomechanical analysis was performed using a biotester biaxial testing system. We used the Mooney-Rivlin strain-energy function to describe corneal material properties. No infection in any case after A-CXL was observed. Biomechanical tests showed that the stress-strain curves of the two A-CXL groups were significantly different from those of the control group (P < 0.01), whereas stress-strain curve of the A-CXL*2 group was similar to that of the A-CXL*1 group (P > 0.05). Delayed epithelial healing and haze were observed 1 month after surgery. Stromal demarcation line depth measured with anterior spectral-domain optical coherence tomography was 187.6 ± 20.4 and 197.1 ± 11.5 μm for the A-CXL1 and A-CXL*2 groups, respectively (P > 0.05). These results show that A-CXL can increase corneal biomechanics in cat eyes. The biomechanical enhancement of cat corneas treated with repeated A-CXL at 1-month intervals was similar to that of performing a one-time A-CXL. Repeated cross-linking procedures at short intervals may increase the risk of adverse reactions, and more caution should be taken in clinical applications.
角膜交联术（CXL）已被证明可通过稳定角膜几何形状和生物力学来有效治疗进行性圆锥角膜和其他角膜扩张疾病。然而，尚不清楚患者是否需要重复 CXL 治疗。本研究旨在探讨重复加速 CXL（A-CXL）后猫眼角膜生物力学硬度的变化和角膜组织病理学特征的变化。在 15 只家猫中，使用 0.1%核黄素处理 10 分钟，然后用 365nm 紫外线 A 照射 3 分钟，光强为 30mW/cm2，进行 A-CXL。角膜（n=30）分为三组：一次性加速角膜交联（A-CXL1 组）、重复加速角膜交联（A-CXL2 组）和未处理对照组。在 A-CXL2 组中，A-CXL 每 1 个月重复一次。术前和术后进行活体眼检查。使用生物测试仪双轴测试系统进行生物力学分析。我们使用 Mooney-Rivlin 应变能函数来描述角膜材料特性。A-CXL 后无感染发生。生物力学测试表明，两组 A-CXL 的应力-应变曲线与对照组有显著差异（P<0.01），而 A-CXL*2 组的应力-应变曲线与 A-CXL*1 组相似（P>0.05）。术后 1 个月观察到上皮愈合延迟和混浊。前节光谱域光学相干断层扫描测量的基质分界线深度分别为 A-CXL1 和 A-CXL*2 组的 187.6±20.4μm 和 197.1±11.5μm（P>0.05）。这些结果表明，A-CXL 可以增加猫眼角膜的生物力学。在 1 个月的间隔内重复进行 A-CXL 可增强猫眼角膜的生物力学，与单次 A-CXL 相似。在短时间间隔内进行多次交联可能会增加不良反应的风险，在临床应用中应更加谨慎。
