Development of a Scheimpflug imaging equipped OCT system to measure gradient refractive index of the lens in the human eye in vivo

项目概要/摘要 人眼的晶状体透镜在一生中不断生长，其大小、形状 内部结构。透镜寿命的增长在透镜内部产生了一种特殊的结构： 梯度分布从透镜表面到透镜中心，梯度分布的特征在于其 纤维细胞浓度、水含量和细胞水平的蛋白质浓度。与此同时， 在透镜内部还建立了一种机制，以保持透镜的梯度结构和健康。在 在功能水平上，梯度蜂窝结构产生透镜的梯度折射率（GRIN）。该透镜 GRIN引起负球面像差，并通过补偿正球面像差来改善眼睛的光学质量 在放松和调节的眼睛中来自角膜的球面像差。更好地理解 透镜GRIN对于屈光和白内障手术领域的眼科护理专业人员非常重要， 他们的手术设计和视觉科学家探索细胞机制的发展 老花眼和白内障。然而，在活体中接近人眼中的透镜GRIN一直是一个挑战 视觉研究者们已经研究了超过世纪。 最近，主要研究者（PI）发现了一种新的原理来处理这一困难的任务， 将Scheimpflug成像（SI）与眼前节光学相干断层扫描（AS-OCT）相结合。这 本计画旨在发展一种新的光线追踪式半导体光学相干断层扫描系统，以量测透镜的梯度折射率 通过应用PI最近取得的突破，包括：（1）发现了 射线跟踪SI和AS-OCT结合在体测量径向透镜梯度折射率的原理 成像;（2）发现射线跟踪SI方法，以确定后透镜表面的点， 反射SI和AS-OCT系统的测量光。新系统的优点包括： (1)构建了一个配备有光线跟踪SI的AS-OCT系统，该系统提供了一种独特的仪器来成像 眼前节，并研究体内透镜的形态和光学特性;（2）对于 第一次在没有任何假设的情况下，在体内精确测量人眼的径向透镜GRIN， （3）首次准确评估人眼透镜厚度， 体内;（4）准确地导出体内人眼的后透镜表面的轮廓;以及（5）估计 老化眼或体内发生白内障的眼的折射率异常。成功 该项目目标的实现最终将使我们能够更好地了解 透镜GRIN及其在正常和有缺陷的眼睛中的潜在细胞机制， 采取有效的干预措施，控制老花眼和白内障的发展。它还将提供一个实质性的 在日常眼部护理中诊断透镜老化的方法学上取得突破， 和恢复勃起的手术。

Project Summary/Abstract The crystalline lens of the human eye grows throughout life with continuous change in its size, shape and internal structure. The lifetime growth of the lens generates a special structure inside the lens: the gradient distribution. From the lens surface to the lens center, the gradient distribution is characterized in its fiber cell concentration, water content and protein concentration at the cellular level. Meanwhile, a cellular mechanism is also established inside the lens to maintain the gradient structure and health of the lens. At the functional level, the gradient cellular structure produces a gradient refractive index (GRIN) of the lens. The lens GRIN causes negative spherical aberration and improves optical quality of the eye by compensating positive spherical aberration from the cornea in both relaxed and accommodated eyes. Better understanding of the lens GRIN is important for eye care professionals in the areas of refractive and cataract surgeries to optimize their surgery design and for vision scientists to explore the cellular mechanisms underlying the developments of presbyopia and cataract. However, accessing the lens GRIN in the human eye in vivo has been a challenge to vision researchers for more than a century. Recently, the Principal Investigator (PI) discovered a novel principle to approach this difficult task by combining Scheimpflug imaging (SI) with anterior segment optical coherence tomography (AS-OCT). This proposed project aims to develop a novel ray-tracing SI equipped AS-OCT system to measure the lens GRIN of the human eye in vivo by applying breakthroughs the PI has recently achieved including: (1) discovery of the principle of in vivo measurement of radial lens GRIN by using a combination of a ray-tracing SI and AS-OCT imaging; (2) discovery of the ray-tracing SI method to identify the point at the posterior lens surface from where the measured lights for both SI and AS-OCT systems were reflected. Advantages of the new system include: (1) constructing a ray-tracing SI equipped AS-OCT system which provides a unique instrument to image the anterior segment of the eye and to study the morphological and optical properties of the lens in vivo; (2) for the first time, accurately measuring radial lens GRIN of the human eye in vivo without any assumption about the optical property of the lens; (3) for the first time, accurately assessing radial lens thickness of the human eye in vivo; (4) accurately deriving profiles of the posterior lens surface of the human eye in vivo; and (5) estimating abnormalities of the refractive index in the aging eye or the eye with cataract development in vivo. Successful accomplishment of the goals of this project will eventually allow us to better understand the functional role of the lens GRIN and its underlying cellular mechanisms in normal and defective eyes and potentially to find effective interventions to control presbyopia and cataract development. It will also present a substantial breakthrough in the methodology for diagnosing lens aging in daily eye care and for revolutionizing refractive and accommodation-restoring surgeries in current clinical practice.