生物力学增强：低剂量辐照角膜交联术与标准德累斯顿方案的比较。

Biomechanical stiffening: Slow low-irradiance corneal crosslinking versus the standard Dresden protocol.

机构信息

From the Laboratory for Ocular Cell Biology (Kling, Hafezi), Center for Applied Biotechnology and Molecular Medicine, University of Zurich, and ELZA Institute AG (Hafezi), Zurich, and the Faculty of Medicine (Hafezi), University of Geneva, Geneva, Switzerland; Roski Eye Institute (Hafezi), University of Southern California, Los Angeles, California, USA.

出版信息

J Cataract Refract Surg. 2017 Jul;43(7):975-979. doi: 10.1016/j.jcrs.2017.04.041.

DOI:10.1016/j.jcrs.2017.04.041

PMID:28823446

Abstract

PURPOSE

To assess whether full biomechanical stiffening can be achieved with corneal crosslinking (CXL) when applying a reduced ultraviolet (UV) fluence during the standard irradiation time.

SETTING

Laboratory of Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland.

DESIGN

Experimental study.

METHODS

Thirty-four freshly enucleated porcine corneas were deepithelialized and soaked with hypoosmolar riboflavin 0.1% solution for 30 minutes. Slow low-irradiance CXL (30 minutes at 1.5 mW/cm, fluence 2.7 J/cm) was compared with standard CXL (30 minutes at 3 mW/cm, fluence 5.4 J/cm). The controls were soaked with riboflavin but not exposed to UV light. Elastic (stress-strain) and viscoelastic (stress-relaxation) 2-dimensional testing was performed with a commercial stress-strain extensometer to quantify the biomechanical stiffening.

RESULTS

Corneas crosslinked with low and standard UV irradiances had a significantly higher mean elastic modulus (65.9 MPa ± 15.7 [SD] and 67.1 ± 15.6 MPa, respectively) than controls (52.4 ± 12.3 MPa) (P < .001). Also, the remaining stress after 120 seconds of stress-relaxation was significantly higher after CXL with low and standard UV irradiances (159 ± 21 kPa and 158 ± 25 kPa, respectively) compared with controls (135 ± 20 kPa) (P ≤ .013). No difference was observed in low and standard irradiances between CXL conditions (P = .64).

CONCLUSIONS

The UV fluence for CXL might be reduced while maintaining the biomechanical efficacy by using a lower UV irradiance and the same irradiation duration. This might open avenues in the treatment of extremely thin corneas.

摘要

目的

评估在标准照射时间内降低紫外线（UV）剂量时，角膜交联（CXL）是否可以实现完全的生物力学僵硬。

设置

苏黎世大学应用生物技术和分子医学中心眼科细胞生物学实验室，瑞士苏黎世。

设计

实验研究。

方法

34 只新鲜眼球被去上皮化，用低渗核黄素 0.1%溶液浸泡 30 分钟。缓慢低辐照度 CXL（1.5 mW/cm，30 分钟，剂量 2.7 J/cm）与标准 CXL（3 mW/cm，30 分钟，剂量 5.4 J/cm）进行比较。对照组用核黄素浸泡但不暴露于 UV 光下。使用商业的应力应变伸长计进行二维弹性（应力-应变）和粘弹性（应力松弛）测试，以量化生物力学僵硬。

结果

用低和标准 UV 辐照度交联的角膜的平均弹性模量（分别为 65.9 MPa ± 15.7 [SD]和 67.1 ± 15.6 MPa）明显高于对照组（52.4 ± 12.3 MPa）（P <.001）。此外，在 120 秒的应力松弛后，低和标准 UV 辐照 CXL 后的剩余应力（分别为 159 ± 21 kPa 和 158 ± 25 kPa）明显高于对照组（135 ± 20 kPa）（P ≤.013）。在低和标准辐照之间，CXL 条件之间没有观察到差异（P =.64）。