Augentagesklinik Spreebogen Berlin, Berlin, Germany.
Klinik für Augenheilkunde, Kepler Universitätsklinikum, Linz, Austria.
Curr Eye Res. 2023 Aug;48(8):719-723. doi: 10.1080/02713683.2023.2205612. Epub 2023 May 5.
To evaluate corneal stiffening of porcine corneas induced by corneal crosslinking (CXL) with constant irradiance as a function of total fluence.
Ninety corneas from freshly enucleated porcine eyes were divided into five groups of 18 eyes. Groups 1-4 underwent epi-off CXL using a dextran-based riboflavin solution and an irradiance of 18 mW/cm, group 5 served as the control group. Groups 1 to 4 were treated with a total fluence of 20, 15, 10.8, and 5.4 J/cm, respectively. Thereafter, biomechanical measurements were performed on 5 mm wide and 6 mm long strips using an uniaxial material tester. Pachymetry measurements were performed on each cornea.
At 10% strain, the stress was 76, 56, 52, and 31% higher in groups 1-4, respectively compared to the control group. The Young's modulus was 2.85 MPa for group 1, 2.53 MPa for group 2, 2.46 MPa for group 3, 2.12 MPa for group 4, and 1.62 MPa for the control group. The difference between groups 1 to 4 and the control group 5 were statistically significant ( = <0.001; = <0.001; = <0.001; = 0.021). In addition, group 1 showed significantly more stiffening than group 4 ( = <0.001), no other significant differences were found. Pachymetry measurements revealed no statistically significant differences among the five groups.
Additional mechanical stiffening can be achieved by increasing the fluence of the CXL. There was no threshold detected up to 20 J/cm. A higher fluence could compensate the weaker effect of accelerated or epi-on CXL procedures.
评估恒定辐照度下猪眼角膜交联（CXL）诱导的角膜硬度变化与总累积剂量的关系。
从新鲜摘取的猪眼摘取 90 只眼角膜，分为 5 组，每组 18 只眼角膜。1-4 组采用基于葡聚糖的核黄素溶液进行 epi-off CXL，辐照度为 18 mW/cm，第 5 组为对照组。1-4 组分别接受 20、15、10.8 和 5.4 J/cm 的总累积剂量。然后，使用单轴材料试验机对 5mm 宽、6mm 长的条带进行生物力学测量。对每只眼角膜进行角膜厚度测量。
在 10%应变下，与对照组相比，1-4 组的应力分别增加了 76%、56%、52%和 31%。1 组的杨氏模量为 2.85 MPa，2 组为 2.53 MPa，3 组为 2.46 MPa，4 组为 2.12 MPa，对照组为 1.62 MPa。1-4 组与对照组 5 之间的差异具有统计学意义（ = <0.001； = <0.001； = <0.001； = 0.021）。此外，1 组的硬度增加明显大于 4 组（ = <0.001），但其他组间无明显差异。角膜厚度测量结果显示 5 组间无统计学差异。
增加 CXL 的累积剂量可以获得额外的机械硬度增强。在 20 J/cm 以内未检测到阈值。更高的累积剂量可以补偿加速或 epi-on CXL 程序的较弱效果。
