Pilot Sudy on Normal and Diseased Corneas with the NASA-

位于眼睛前面的透明角膜不仅起到了折射介质的作用，将光线聚焦到视网膜上，帮助我们看到东西，而且还充当了眼睛前面的主要屏障和墙。严重的角膜疾病会导致混浊和失明。眼角膜疾病和损伤是当今美国人去眼科诊所就诊的主要原因。这些疾病也是最令人痛苦的眼疾之一。角膜研究的两个重要领域是：1)探索和了解角膜透明的分子基础；2)分析角膜伤口愈合和炎症的分子性质。 我们已经开发了一种新的临床设备来了解晶状体中发生的分子变化，NASA-NEI动态光散射(DLS)设备。实验室研究表明，它在检测白内障最早发生的变化方面具有潜力。对晶状体的临床研究也显示了良好的重测重复性、对微小变化的敏感度以及非侵入性体内DLS临床系统的安全性。我们在动物身上进行了实验室研究，以确定DLS设备是否也适用于研究角膜。我们发现，在正常状态下，它在检测角膜不同层/室的分子差异方面也确实有用。此外，我们发现，在角膜损伤后，如激光光折变手术、化学损伤和擦伤后，DLS可以检测到使用裂隙灯生物显微镜等光学设备无法明显或检测到的变化。因此，DLS还有望成为一种非侵入性的在体设备，用于研究正常状态和疾病状态(如损伤或手术后或遗传性疾病)的角膜，在这项旨在了解角膜透明度的分子基础的研究中，我们将研究年轻人和老年人(志愿者)的正常角膜以及混浊、不透明的角膜，并确定该设备用于角膜使用的安全性和重复性。在初步测试中，目前用于研究白内障的DLS设备被确定不适合角膜。这是因为角膜和晶状体之间的厚度不同(人类角膜的厚度为0.5 mm，而人类晶状体的厚度为3-4 mm)，因此氦-霓虹灯光束的入射角度与APD光探测器的角度不正确。因此，需要制造一种新的NASA-NEI角膜DLS设备，该设备即将完成。

The transparent cornea, located in the front of the eye, acts not only as a refracting medium to focus light on the retina and help us see, but also serves as the main barrier and wall in the front of the eye. Serious disease of the cornea leads to opacification and blindness. Corneal diseases and injuries are the leading reason for visits to eye care clinics in the U.S. today. These diseases are also some of the most painful eye disorders. Two important areas for research on the cornea are: 1) to explore and understand the molecular basis of corneal transparency, and 2) to analyse the molecular nature of corneal wound healing and inflammation. We have developed a new clinical device to understand molecular changes that occur in the lens, the NASA-NEI Dynamic Light Scatering (DLS) device. Laboratory studies have shown its potential in the detection of the earliest changes occuring in cataracts. Clinical studies on the lens have also shown good test-retest reproducibility, sensitivity to pick up small changes, and safety of the non-invasive, in vivo DLS clinical system. We conducted laboratory studies in animals to determine if the DLS device is also useful to study the cornea. We found that it is also indeed useful in detecting molecular differences in various layers/compartments of the cornea in the normal state. In addition, we found that after corneal injury such as after laser photorefractive surgery, chemical injury and scraping, the DLS could detect changes which are not apparent or detectable using optical devices such as the slit lamp biomicroscope. Hence, the DLS also holds promise as a non-invasive, in vivo device to study the cornea in the normal state as well as in diseased states (such as after injury or surgery or in inherited genetic diseases), and in studies to understand the molecular basis of corneal transparency In this pilot project, we will study the normal cornea in young and older persons (volunteers) as well as cloudy, opaque corneas, as well as determine the safety and reproducibility of the device for corneal use. In preliminary testing, it was determined that the current DLS device used to study cataracts is not properly suited for the cornea. This is because of the difference in thickness between the cornea and the lens (0.5 mm in the human cornea versus 3-4 mmm in the human lens), so that the angle of entry of the Helium Neon Light beam versus the angle of the APD light detector is not correct. Hence a new NASA-NEI DLS device for the cornea needed to be made and is nearing completion.