Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
Sci Rep. 2024 Sep 5;14(1):20667. doi: 10.1038/s41598-024-71276-8.
Myopia is a common ocular condition characterized by biomechanical weakening revealed by increasing creep rate, cyclic softening scleral thinning, change of collagen fibril crimping, and excessive elongation of the posterior sclera resulting in blurred vision. Animal studies support scleral crosslinking as a potential treatment for myopia control by strengthening the weakened sclera and slowing scleral expansion. While multiple studies investigated aspects of the biomechanical weakening and strengthening effects in myopia and after scleral crosslinking, a comprehensive analysis of the underlying mechanical changes including the effect of vehicle injections is still missing. The purpose of this study was to provide a comprehensive analysis of biomechanical changes by scleral inflation testing in experimental myopia, after retrobulbar vehicle injections and scleral crosslinking using genipin in tree shrews. Our results suggest that biomechanical weakening in myopia involves an increased creep rate and higher strain levels at which collagen fibers uncrimp. Both weakening effects were reduced after scleral crosslinking using genipin at doses that were effective in slowing myopia progression. Vehicle injections increased mechanical hysteresis and had a small but significant effect on slowing myopia progression. Also, our results support scleral crosslinking as a potential treatment modality that can prevent or counteract scleral weakening effects in myopia. Furthermore, vehicle solutions may cause independent biomechanical effects, which should be considered when developing and evaluating scleral crosslinking procedures.
近视是一种常见的眼部疾病，其特征是生物力学减弱，表现为蠕变率增加、巩膜周期性软化、胶原纤维卷曲改变以及后巩膜过度伸长，导致视力模糊。动物研究支持巩膜交联作为一种潜在的近视控制治疗方法，通过增强薄弱的巩膜和减缓巩膜扩张来实现。虽然多项研究调查了近视和巩膜交联后生物力学减弱和增强的各个方面，但对于潜在的机械变化，包括载体注射的影响，仍缺乏全面分析。本研究的目的是通过对实验性近视、球后载体注射和树鼩中使用京尼平进行巩膜交联后的巩膜膨胀试验，提供生物力学变化的综合分析。我们的结果表明，近视中的生物力学减弱涉及蠕变率增加和胶原纤维解卷曲时的应变水平升高。两种减弱效应在使用京尼平进行巩膜交联后均降低，而京尼平的剂量对于减缓近视进展是有效的。载体注射增加了力学滞后，并且对减缓近视进展有微小但显著的影响。此外，我们的结果支持巩膜交联作为一种潜在的治疗方法，可以预防或对抗近视中的巩膜减弱效应。此外，载体溶液可能会引起独立的生物力学效应，在开发和评估巩膜交联程序时应考虑这些效应。
