Torres-Netto Emilio A, Kling Sabine, Hafezi Nikki, Vinciguerra Paolo, Randleman J Bradley, Hafezi Farhad
J Refract Surg. 2018 Nov 1;34(11):768-774. doi: 10.3928/1081597X-20180830-01.
To evaluate the impact of varying treatment time on the efficacy of iontophoresis-assisted transepithelial corneal cross-linking (I-CXL) in ex vivo porcine corneas.
One hundred twelve porcine corneas with intact epithelium were divided into 7 groups and analyzed. Groups 1, 2, and 3 received standard epitheliumoff CXL (S-CXL) with hypo-osmolaric 0.1% riboflavin and 30 minutes of ultraviolet-A (UV-A) irradiation at 3 mW/cm, 10 minutes at 9 mW/cm, or were not irradiated (controls). Groups 4, 5, 6, and 7 received I-CXL for either 60 minutes at 1.5 mW/cm, 30 minutes at 3 mW/cm, 10 minutes at 9 mW/cm, or were not irradiated (controls). Elastic modulus and stress after relaxation of 5-mm wide corneal strips were analyzed.
In the S-CXL groups, significant differences (P ≤ .05) in stress-strain extensometry were found between controls and 3 mW/cm for 30 minutes (group 1) and between controls and 9 mW/cm for 10 minutes (group 2). In the I-CXL groups, only the 1.5 mW/cm for 60 minutes setting (group 4) showed a significant stiffening effect. All epithelium-off groups provided a stiffening effect significantly stronger than I-CXL: with a stiffening effect of 149% and 112%, groups 1 and 4 were the groups with greater elastic modulus between the S-CXL and I-CXL groups, respectively.
The biomechanical effect of I-CXL increased significantly when using a low irradiance/long irradiation setting. Oxygen diffusion thus represents a limiting factor even when riboflavin penetration is improved via iontophoresis. Still less effective than S-CXL, this modification may help establish transepithelial CXL as a treatment option in selected cases. [J Refract Surg. 2018;34(11):768-774.].
评估不同治疗时间对离体猪角膜中离子电渗辅助跨上皮角膜交联术（I-CXL）疗效的影响。
将112只上皮完整的猪角膜分为7组并进行分析。第1、2和3组接受标准的去上皮角膜交联术（S-CXL），使用低渗0.1%核黄素，分别在3 mW/cm下进行30分钟的紫外线A（UV-A）照射、在9 mW/cm下进行10分钟的照射，或不进行照射（对照组）。第4、5、6和7组分别在1.5 mW/cm下接受60分钟、在3 mW/cm下接受30分钟、在9 mW/cm下接受10分钟的I-CXL，或不进行照射（对照组）。分析5毫米宽角膜条放松后的弹性模量和应力。
在S-CXL组中，对照组与3 mW/cm照射30分钟的组（第1组）以及对照组与9 mW/cm照射10分钟的组（第2组）之间，应力应变引伸计存在显著差异（P≤0.05）。在I-CXL组中，只有1.5 mW/cm照射60分钟的设置（第4组）显示出显著的硬化效果。所有去上皮组提供的硬化效果明显强于I-CXL：第1组和第4组分别是S-CXL组和I-CXL组中弹性模量增加更大的组，硬化效果分别为149%和112%。
当使用低辐照度/长时间照射设置时，I-CXL的生物力学效应显著增加。因此，即使通过离子电渗改善了核黄素的渗透，氧扩散仍是一个限制因素。这种改良虽然仍不如S-CXL有效，但可能有助于在某些特定情况下将跨上皮角膜交联术确立为一种治疗选择。[《屈光手术杂志》。2018；34(11):768 - 774。]
