Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, RJ, Brazil; Federal University of the State of Rio de Janeiro (UNIRIO), Brazil.
J Biomech. 2019 Aug 27;93:209-212. doi: 10.1016/j.jbiomech.2019.06.011. Epub 2019 Jun 27.
The objective of this non-randomized trial was comparison of two-year changes in dynamic corneal response (DCR) between 18 mW/cm (5- min) and 9 mW/cm (10-min) cross-linking (CXL) protocols, using novel stiffness parameters and correlating them to clinical indices. The two groups were evaluated before and 2 years after the procedure using Corvis ST (Oculus Optikgeräte GmbH, Germany) and DCR parameters such as deformation amplitude ratio at 1 mm and 2 mm (DA ratio-1 mm and DA ratio-2 mm) and integrated radius and stiffness parameters at A1 (SP-A1). Two-year follow-up was completed for 16 of the 30 eyes in the 5-min group and 21 of the 25 eyes in the 10-min group; data from those who were lost to follow-up was not included in the analyses. Mean age at baseline was 21.7 ± 4.9 and 21.5 ± 5.2 years in the 5- and 10-min groups, respectively (P = 0.895). At 2 years after CXL, in the 5-min group, the reduction in integrated radius (-1.12 ± 1.27 mm, P = 0.003) was significant, and the increase in SP-A1 (7.11 ± 14.86 mmHg/mm, P = 0.075) was borderline, while in the 10-min group, the decrease in DA ratio-2 mm (-0.43 ± 0.58, P = 0.003) and integrated radius (-1.89 ± 1.72 mm, P < 0.001), and increase in SP-A1 (7.67 ± 10.92 mmHg/mm, P = 0.004) were significant. In both groups, the strongest and significant correlation was observed between DCR parameters and changes in radius of curvature. In conclusion, results indicated corneal strengthening with both protocols especially with the 9 mW/cm. Corvis ST indices can provide "in vivo" biomechanical evidence on the efficacy of CXL that may occur prior to clinical indices.
本非随机试验的目的是比较 18mW/cm（5 分钟）和 9mW/cm（10 分钟）交联（CXL）方案在两年内对动态角膜反应（DCR）的影响，使用新型硬度参数，并将其与临床指标相关联。两组患者在治疗前和治疗后 2 年分别使用 Corvis ST（德国 Oculus Optikgeräte GmbH）和 DCR 参数进行评估，如 1mm 和 2mm 处的变形幅度比（DA 比-1mm 和 DA 比-2mm）以及 A1 处的整合半径和硬度参数（SP-A1）。5 分钟组中有 16 只眼和 10 分钟组中有 21 只眼完成了两年的随访；失访者的数据未纳入分析。两组患者的平均年龄分别为 21.7±4.9 岁和 21.5±5.2 岁（P=0.895）。在 CXL 后 2 年，5 分钟组中整合半径减少（-1.12±1.27mm，P=0.003），SP-A1 增加（7.11±14.86mmHg/mm，P=0.075）接近显著，而在 10 分钟组中，DA 比-2mm 减少（-0.43±0.58，P=0.003）和整合半径减少（-1.89±1.72mm，P<0.001），以及 SP-A1 增加（7.67±10.92mmHg/mm，P=0.004）均显著。在两组中，DCR 参数与曲率半径变化之间的相关性最强且最显著。总之，结果表明两种方案均可增强角膜强度，尤其是 9mW/cm 方案。Corvis ST 指数可提供 CXL 疗效的“体内”生物力学证据，该证据可能先于临床指标出现。
