Noninvasive assessment of the cornea by diffusion OCT

圆锥角膜是一种角膜退行性疾病，是导致视力下降的主要原因。 在美国的生活质量，往往导致角膜移植。屈光手术后的扩张是一种 尽管目前进行了筛查，但在明显低风险的患者中可能发生威胁视力的并发症 技术.角膜的生物力学特性在这些疾病中起着核心作用，但诊断 仍然植根于形状测量，因为医生缺乏生物力学变化的直接测量。而 有几种方法已经显示出解决这一差距的早期希望，大多数需要接触或扰动 不能在空间上分辨生物力学特性，或者涉及昂贵的光学系统。 为了解决对角膜的直接生物力学测量的需求以及其他生物力学测量的局限性， 方法，我们引入相位去相关OCT（phd-OCT）。Phd-OCT利用光学相干性 断层扫描（OCT），以量化随机纳米级的流动性，这是有关的强度和凝聚力的 角膜初步结果有力地支持了该方法的原理、可行性和潜在优势。 我们的目标是：（1）改进我们的方法，以优化检测灵敏度和速度，以及（2） 确定该技术是否在临床上有用。我们将通过以下目标实现这些目标： 1.开发并验证用于角膜成像的迁移率敏感型phd-OCT。谱域OCT将 用于眼前节相位去相关成像，并优化分析算法。的 将使用体模和扭转流变仪对系统进行验证。 2.研究生理因素（眼内压（IOP）、水合作用和 温度）。在猪和人供体球中的析因设计实验将建立以下灵敏度： phd-OCT测量值与潜在混杂因素之间的关系。 3.开发和验证数据采集和处理方法，以实现临床测试。GPU 处理和机器学习将被配置为最小化处理时间。扫描模式将是 优化以最小化扫描时间并返回临床有用的数据。 4.评估临床流动敏感OCT成像的可行性和初步诊断性能 的角膜。首次人体研究将描述重复性，并测试phd-OCT 在LASIK角膜瓣的区域中移动性测量值增加，而在CXL中移动性测量值减少。 预期结果：拟定的研究将建立一种新的非接触式角膜成像方法 生物力学特性，具有解决当前和新兴方法的许多缺点的潜力。 成功可能导致早期发现扩张风险，并允许更适当的时机和定制 角膜治疗。未来将数据集成到计算模型中有可能极大地影响 通过推动从经验规划和风险分析向患者特定策略的转变，

Keratoconus is a degenerative disease of the cornea that is a major cause of reduced vision-related quality of life in the United States, often leading to corneal transplantation. Ectasia after refractive surgery is a vision-threatening complication that can occur in apparently low-risk patients despite current screening technology. The biomechanical properties of the cornea play a central role in these diseases, but diagnostics are still rooted in shape measures because doctors lack direct measures of biomechanical change. While several methods have shown early promise for addressing this gap, most require contact with or perturbation of the cornea, cannot spatially resolve biomechanical properties, or involve expensive optical systems. To address the need for direct biomechanical measurement of the cornea and the limitations of other approaches, we introduce phase-decorrelation OCT (phd-OCT). Phd-OCT makes use optical coherence tomography (OCT) to quantify random nanoscale mobility that is related to the strength and cohesion of the cornea. Preliminary results strongly support the rationale, feasibility and potential advantages of the approach. Our objectives are: (1) to refine our method to optimize detection sensitivity and speed, and (2) to determine if the technique is clinically useful. We will achieve these objectives through the following aims: 1. To develop and validate mobility-sensitive phd-OCT for corneal imaging. Spectral-domain OCT will be used for anterior segment phase-decorrelation imaging and the analysis algorithm will be optimized. The system will be validated using phantoms and torsional rheometry. 2. To investigate the potential influence of physiological factors (intraocular pressure (IOP), hydration, and temperature). Factorial design experiments in porcine and human donor globes will establish the sensitivity of phd-OCT measurements to potential confounders. 3. To develop and validate data acquisition and processing methods to enable clinical testing. GPU processing and machine learning will be configured to minimize processing time. Scan patterns will be optimized to minimize scan time and return clinically useful data. 4. To assess feasibility and preliminary diagnostic performance of clinical mobility-sensitive OCT imaging of the cornea. A first-in-human study will characterize repeatability and test the hypotheses that phd-OCT mobility measurements are increased in the region of a LASIK flap and decreased in CXL. Expected Outcomes: The proposed studies will establish a new, non-contact method for imaging corneal biomechanical properties with the potential to address many shortcomings of current and emerging methods. Success could lead to earlier detection of of ectasia risk and allow more appropriate timing and customization of corneal treatments. Future integration of data into computational models has the potential to greatly impact the field by driving a shift from empirical planning and risk analysis to patient-specific strategies.