Optical Coherence Tomography-Aided Differential Diagnosis and Treatment of Irregular Corneas

项目摘要 为了看得更清楚，角膜必须保持近乎完美的清晰度和形状。几种疾病过程可以扭曲 角膜形状和视力下降。这些包括扩张/圆锥角膜（基质变薄和肿胀）、原发性 上皮变形（隐形眼镜相关翘曲、干眼、上皮基底膜营养不良），以及 基质变化（瘢痕、基质营养不良、手术）。其中一些条件可能与标准 前地形，但需要非常不同的治疗。因此，该项目的目标是使用光学 相干断层扫描（OCT）是一种具有微米级分辨率的三维成像技术， 区分不同类型的角膜形状不规则。OCT的独特能力是测量 上皮厚度和后部地形将用于开发新的分期和监测指标， 扩张和原发性上皮变形。我们还将改进角膜基质不规则的治疗 通过结合OCT规划和地形引导准分子激光消融，这只是最近才成为 我们的总体目标是提高早期发现，鉴别诊断，分期， 通过使用先进的光学成像和激光技术监测和治疗不规则角膜， 实现以下具体目标： (1)开发一个基于OCT的系统来分类和评估角膜形状不规则。标准角膜 地形图仅测量前角膜表面，并且其本身不能区分不同的角膜表面。 不规则的原因。在一项横断面临床研究中，我们将开发OCT图的数学分析， 角膜前后地形图、上皮和角膜厚度测量，以提高早期检测， 不规则性的分类和分期，包括扩张、上皮变形和基质变化。 (2)开发OCT指标，以更灵敏地检测圆锥角膜进展。标准前路 地形参数如最大角膜曲率测量具有较差的再现性和较差的检测灵敏度 早期疾病。我们的初步结果表明，OCT上皮和后部地形测量是 对早期圆锥角膜更敏感，重复性更好。这样可以更及时地识别 需要胶原蛋白交联来稳定角膜的患者。将检测进展的早期检测 在亚临床圆锥角膜患者的纵向研究中。 (3)开发OCT和地形图引导的激光治疗性角膜切削术（PTK）治疗不规则角膜。我们 已经证明，OCT计划的经上皮PTK可以显著改善患有以下疾病患者的视力： 疤痕或不规则角膜。我们建议进一步改善手术效果，使用新的可用 地形图引导准分子激光，已被批准用于激光辅助原位角膜磨镶术（LASIK）， 正常眼睛，但尚未在PTK中进行测试。我们计划进行OCT和地形图的临床试验 引导PTK用于角膜瘢痕、基质营养不良和其他不规则的患者。

PROJECT SUMMARY To see well, the cornea must maintain near perfect clarity and shape. Several disease processes can distort corneal shape and degrade vision. These include ectasia/keratoconus (stromal thinning and bulging), primary epithelial deformation (contact lens-related warpage, dry eye, epithelial basement membrane dystrophy), and stromal changes (scar, stromal dystrophy, surgery). Some of these conditions can appear similar on standard anterior topography and yet require very different treatments. Therefore a goal of this project is to use optical coherence tomography (OCT), a 3-dimensional imaging technology with micrometer-level resolution, to differentiate between different types of corneal shape irregularities. The unique ability of OCT to measure epithelial thickness and posterior topography will be used to develop new metrics for staging and monitoring of ectasia and primary epithelial deformation. We will also improve the treatment of corneal stromal irregularities by combining OCT planning and topography-guided excimer laser ablation, which has only recently become available in the U.S. Our overall goal is to improve the early detection, differential diagnosis, staging, monitoring, and treatment of irregular corneas by using advanced optical imaging and laser technologies to achieve the following Specific Aims: (1) Develop an OCT-based system to classify and evaluate corneal shape irregularities. Standard corneal topography only measures the anterior corneal surface and cannot by itself differentiate between different causes of irregularities. In a cross-sectional clinical study, we will develop mathematical analyses of OCT maps of corneal anterior and posterior topography, epithelium, and pachymetry to improve the early detection, classification, and staging of irregularities including ectasia, epithelial deformations, and stromal changes. (2) Develop OCT metrics for more sensitive detection of keratoconus progression. Standard anterior topographic parameters such as maximum keratometry have poor reproducibility and poor detection sensitivity in early disease. Our preliminary results show that OCT epithelial and posterior topographic measurements are more sensitive to early keratoconus and have better repeatability. This could enable more timely identification of patients who need collagen crosslinking to stabilize the cornea. Early detection of progression will be tested in a longitudinal study of patients with subclinical keratoconus. (3) Develop OCT-and-topography guided phototherapeutic keratectomy (PTK) for irregular corneas. We have demonstrated that transepithelial PTK with OCT planning can significantly improve vision for patients with scarred or irregular corneas. We propose to further improve operative results using the newly available topography-guided excimer laser, which has been approved for laser-assisted in situ keratomileusis (LASIK) in normal eyes but has not yet been tested in PTK. We plan to conduct a clinical trial of OCT-and-topography guided PTK for patients with corneal scars, stromal dystrophies, and other irregularities.