Seven Ibrahim, Sinha Roy Abhijit, Dupps William J
From Cole Eye Institute (Seven, Sinha Roy, Dupps), Ocular Biomechanics and Imaging Laboratory, and the Department of Biomedical Engineering (Seven, Dupps), Lerner Research Institute, Cleveland Clinic, and the Department of Chemical and Biomedical Engineering (Seven), Cleveland State University, Cleveland, Ohio, USA; Narayana Netralaya (Sinha Roy), Bangalore, India.
From Cole Eye Institute (Seven, Sinha Roy, Dupps), Ocular Biomechanics and Imaging Laboratory, and the Department of Biomedical Engineering (Seven, Dupps), Lerner Research Institute, Cleveland Clinic, and the Department of Chemical and Biomedical Engineering (Seven), Cleveland State University, Cleveland, Ohio, USA; Narayana Netralaya (Sinha Roy), Bangalore, India.
J Cataract Refract Surg. 2014 Jun;40(6):943-53. doi: 10.1016/j.jcrs.2014.03.019. Epub 2014 Apr 24.
To test the hypothesis that spatially selective corneal stromal stiffening can alter corneal astigmatism and assess the effects of treatment orientation, pattern, and material model complexity in computational models using patient-specific geometries.
Cornea and Refractive Surgery Service, Academic Eye Institute, Cleveland, Ohio, USA.
Computational modeling study.
Three-dimensional corneal geometries from 10 patients with corneal astigmatism were exported from a clinical tomography system (Pentacam). Corneoscleral finite element models of each eye were generated. Four candidate treatment patterns were simulated, and the effects of treatment orientation and magnitude of stiffening on anterior curvature and aberrations were studied. The effect of material model complexity on simulated outcomes was also assessed.
Pretreatment anterior corneal astigmatism ranged from 1.22 to 3.92 diopters (D) in a series that included regular and irregular astigmatic patterns. All simulated treatment patterns oriented on the flat axis resulted in mean reductions in corneal astigmatism and depended on the pattern geometry. The linear bow-tie pattern produced a greater mean reduction in astigmatism (1.08 D ± 0.13 [SD]; range 0.74 to 1.23 D) than other patterns tested under an assumed 2-times increase in corneal stiffness, and it had a nonlinear relationship to the degree of stiffening. The mean astigmatic effect did not change significantly with a fiber- or depth-dependent model, but it did affect the coupling ratio.
In silico simulations based on patient-specific geometries suggest that clinically significant reductions in astigmatism are possible with patterned collagen crosslinking. Effect magnitude was dependent on patient-specific geometry, effective stiffening pattern, and treatment orientation.
Proprietary or commercial disclosures are listed after the references.
验证空间选择性角膜基质硬化可改变角膜散光这一假设，并在使用患者特异性几何结构的计算模型中评估治疗方向、模式和材料模型复杂性的影响。
美国俄亥俄州克利夫兰市学术眼科研究所角膜与屈光手术服务部。
计算建模研究。
从临床断层扫描系统（Pentacam）导出10例角膜散光患者的三维角膜几何结构。生成每只眼睛的角膜巩膜有限元模型。模拟四种候选治疗模式，研究治疗方向和硬化程度对前表面曲率和像差的影响。还评估了材料模型复杂性对模拟结果的影响。
在包括规则和不规则散光模式的一组病例中，治疗前角膜前表面散光范围为1.22至3.92屈光度（D）。所有模拟的以平轴为方向的治疗模式均导致角膜散光平均降低，且取决于模式几何形状。在假定角膜硬度增加2倍的情况下，线性领结模式产生的散光平均降低幅度（1.08 D±0.13[标准差]；范围0.74至1.23 D）大于其他测试模式，并且它与硬化程度呈非线性关系。纤维或深度依赖性模型的平均散光效应没有显著变化，但确实影响耦合率。
基于患者特异性几何结构的计算机模拟表明，通过模式化胶原交联可实现临床上显著降低散光。效果大小取决于患者特异性几何结构、有效硬化模式和治疗方向。
专有或商业披露在参考文献之后列出。
