Wollensak Gregor, Iomdina Elena
Department of Ophthalmology, Eye Laser Institute, Martin-Luther-University, Halle, Germany.
J Cataract Refract Surg. 2009 Mar;35(3):540-6. doi: 10.1016/j.jcrs.2008.11.036.
To test the biomechanical efficiency of corneal crosslinking with riboflavin without epithelial debridement (C3-R).
Moscow Helmholtz Research Institute of Eye Diseases, Moscow, Russia.
The left eyes of rabbits were crosslinked using standard crosslinking including epithelial removal (Group 1), using benzalkonium chloride-containing proxymetacaine eyedrops without epithelial removal (Group 2), or using preservative-free oxybuprocaine eyedrops without epithelial removal (Group 3). All left eyes received riboflavin solution and were irradiated with an ultraviolet-A double diode for 30 minutes (irradiance 3 mW/cm(2)). The animals were killed 1 day after crosslinking. Biomechanical and histological analyses were performed.
Fourteen eyes were evaluated. There was a statistically significant increase in Young's modulus in Group 1 (102.45%) and in Group 2 (21.30%). In Group 3, no biomechanical changes were measured. Histology showed complete cell loss of keratocytes and endothelium in Group 1 and inhomogeneous keratocyte loss down to 200.0 microm in Group 2. No changes were observed in Group 3.
Corneal crosslinking without epithelial debridement reduced the biomechanical effect by approximately one fifth compared with standard crosslinking, probably because of restricted and inhomogeneous stromal distribution of riboflavin. The cytotoxic damage was restricted to 200.0 microm stromal depth, which is an advantage over the standard method. Therefore, C3-R is not recommended for the routine treatment of keratoconus but primarily for cases with a corneal thickness less than 400.0 microm in which standard crosslinking cannot be used without serious risk to the endothelium.
测试不进行上皮去除的核黄素角膜交联术(C3-R)的生物力学效率。
俄罗斯莫斯科赫尔姆霍茨眼疾病研究所。
对兔的左眼进行交联,其中一组采用包括上皮去除的标准交联术(第1组),一组使用含苯扎氯铵的丙美卡因滴眼液且不进行上皮去除(第2组),另一组使用无防腐剂的奥布卡因滴眼液且不进行上皮去除(第3组)。所有左眼均接受核黄素溶液,并使用紫外线-A双二极管照射30分钟(辐照度3 mW/cm²)。交联术后1天处死动物,进行生物力学和组织学分析。
共评估了14只眼。第1组(102.45%)和第2组(21.30%)的杨氏模量有统计学意义的增加。第3组未检测到生物力学变化。组织学显示,第1组角膜细胞和内皮细胞完全丧失,第2组角膜细胞丧失不均匀,深度达200.0微米。第3组未观察到变化。
与标准交联术相比,不进行上皮去除的角膜交联术使生物力学效应降低了约五分之一,这可能是由于核黄素在基质中的分布受限且不均匀。细胞毒性损伤局限于基质深度200.0微米,这是优于标准方法的一点。因此,不建议将C3-R用于圆锥角膜的常规治疗,而主要用于角膜厚度小于400.0微米的病例,在这些病例中,使用标准交联术会对内皮造成严重风险。