Wollensak Gregor, Spoerl Eberhard, Seiler Theo
Department of Ophthalmology, Technical University of Dresden, Dresden, Germany.
J Cataract Refract Surg. 2003 Sep;29(9):1780-5. doi: 10.1016/s0886-3350(03)00407-3.
To evaluate the biomechanical effect of combined riboflavin-ultraviolet A (UVA) treatment on porcine and human corneas.
Department of Ophthalmology, Technical University of Dresden, Dresden, Germany.
Corneal strips from 5 human enucleated eyes and 20 porcine cadaver corneas were treated with the photosensitizer riboflavin and irradiated with 2 double UVA diodes (370 nm, irradiance = 3 mW/cm2) for 30 minutes. After cross-linking, static stress-strain measurements of the treated and untreated corneas were performed using a microcomputer-controlled biomaterial tester with a prestress of 5 x 10(3) Pa.
There was a significant increase in corneal rigidity after cross-linking, indicated by a rise in stress in treated porcine corneas (by 71.9%) and human corneas (by 328.9%) and in Young's modulus by the factor 1.8 in porcine corneas and 4.5 in human corneas. The mean central corneal thickness was 850 microm +/- 70 (SD) in porcine corneas and 550 +/- 40 microm in human corneas.
Riboflavin-UVA-induced collagen cross-linking led to an increase in mechanical rigidity in porcine corneas and an even greater increase in human corneas. As collagen cross-linking is maximal in the anterior 300 microm of the cornea, the greater stiffening effect in human corneas can be explained by the relatively larger portion of the cornea being cross-linked in the overall thinner human cornea.
评估核黄素 - 紫外线A（UVA）联合治疗对猪角膜和人角膜的生物力学效应。
德国德累斯顿工业大学眼科。
对5只人摘除眼球的角膜条和20只猪尸体角膜用光敏剂核黄素进行处理，并用2个双UVA二极管（370纳米，辐照度 = 3毫瓦/平方厘米）照射30分钟。交联后，使用微机控制的生物材料测试仪，在5×10³帕的预应力下，对处理过和未处理过的角膜进行静态应力 - 应变测量。
交联后角膜硬度显著增加，处理过的猪角膜应力增加（71.9%），人角膜应力增加（328.9%），猪角膜的杨氏模量增加1.8倍，人角膜增加4.5倍。猪角膜平均中央角膜厚度为850微米±70（标准差），人角膜为550±40微米。
核黄素 - UVA诱导的胶原交联导致猪角膜机械硬度增加，人角膜增加更为明显。由于胶原交联在角膜前300微米处最大，人角膜中更大的硬化效应可以通过在整体较薄的人角膜中交联的角膜部分相对较大来解释。
