From the Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA.
From the Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA.
J Cataract Refract Surg. 2017 Nov;43(11):1458-1463. doi: 10.1016/j.jcrs.2017.07.037.
To quantify corneal mechanical changes induced by corneal crosslinking (CXL) procedures of different ultraviolet-A (UVA) intensity and exposure time using Brillouin microscopy.
University of Maryland, College Park, Maryland, USA.
Experimental study.
Porcine cornea samples were debrided of epithelia and soaked with riboflavin 0.1% solution. Samples were exposed to a standard 5.4 J/cm of UVA radiation with varying intensity and exposure time as follows: 3 mW/cm for 30.0 minutes, 9 mW/cm for 10.0 minutes, 34 mW/cm for 2.65 minutes, and 50 mW/cm for 1.80 minutes. Using Brillouin microscopy, the Brillouin modulus for each sample was computed as a function of radiation intensity/exposure time. For validation, the Young's modulus was found with the stress-strain test and compared at each irradiation condition.
The standard 3 mW/cm irradiance condition produced a significantly larger increase in corneal Brillouin modulus than the 9 mW/cm (P ≤ .05), 34 mW/cm (P ≤ .01), and 50 mW/cm (P ≤ .01) conditions. Depth analysis showed similar anterior sections of the standard and 9 mW/cm conditions but significantly less stiffening in the central and posterior of the 9 mW/cm condition. The stiffening of the standard protocol was significantly larger in all sections of the 34 mW/cm and 50 mW/cm conditions (P ≤ .01). The overall change in Brillouin-derived Brillouin modulus correlated with the increase in Young's modulus (R = 0.98).
At a constant UVA light dose, accelerating the irradiation process decreased CXL stiffening. Brillouin analysis showed that accelerated protocols were especially ineffective in the deeper portions of the cornea.
使用布里渊显微镜定量测量不同紫外线 A（UVA）强度和照射时间的角膜交联（CXL）程序引起的角膜力学变化。
美国马里兰大学帕克分校。
实验研究。
猪角膜标本去除上皮并浸泡在核黄素 0.1%溶液中。样品分别以以下不同强度和照射时间暴露于标准的 5.4 J/cm UVA 辐射：3 mW/cm 照射 30.0 分钟，9 mW/cm 照射 10.0 分钟，34 mW/cm 照射 2.65 分钟，50 mW/cm 照射 1.80 分钟。使用布里渊显微镜，根据辐射强度/照射时间计算每个样品的布里渊模量。为了验证，通过应力-应变测试找到杨氏模量，并在每个照射条件下进行比较。
标准的 3 mW/cm 辐照度条件下角膜布里渊模量的增加明显大于 9 mW/cm（P≤0.05）、34 mW/cm（P≤0.01）和 50 mW/cm（P≤0.01）条件。深度分析表明，标准和 9 mW/cm 条件的前节相似，但 9 mW/cm 条件的中央和后节硬度降低明显。在 34 mW/cm 和 50 mW/cm 条件的所有节段中，标准方案的硬度增加明显更大（P≤0.01）。由布里渊衍生的布里渊模量的整体变化与杨氏模量的增加相关（R=0.98）。
在恒定的 UVA 光剂量下，加速照射过程会降低 CXL 硬度。布里渊分析表明，加速方案在角膜的深层部位效果特别差。
