视网膜内核层微细血管的自适应光学成像研究

发布时间：2018-01-08 03:30

本文关键词：视网膜内核层微细血管的自适应光学成像研究　出处：《中国科学院研究生院(长春光学精密机械与物理研究所)》2016年博士论文　论文类型：学位论文

【摘要】：内分泌疾病,如糖尿病、高血压等在早期就会在10μm以下直径的视网膜微细血管上出现血管瘤、棉絮斑等症状,对视网膜微细血管的成像检查可以及时对内分泌病变做早期诊断。但是观测视网膜时必须放大瞳孔,引入强烈的人眼像差,使医学临床所用的检眼镜只能看清直径15?m以上的微细血管图像。只有结合自适应光学技术,通过实时探测并且校正人眼的像差,才能得到3μm的高分辨成像效果。但是,视网膜为10层半透明组织结构,10μm以下直径的微细血管位于数十微米厚的内核层中,而人眼结构参数各异,内核层微细血管的快速定位成为非常棘手的问题,另外,微细血管成像对比度低、自适应成像视场小也是亟需解决的问题。本论文针对人眼的光学特性,对自适应成像光路系统做了创新性设计。提出了以视觉细胞层作为基准位置,对内核层微细血管进行定位成像的方法;统计了不同人眼的微细血管层公共区域;利用模型眼对人眼进行仿真,得到了人眼有效焦距和人眼轴长之间的关系,能够准确计算出内核层像面位置,解决了人眼结构参数各异的问题。设计了微细血管定位成像实验:1)利用视标引导方式对视网膜进行横向定位,确定了视标位于眼前1D位置可保持人眼盯视标的准确性和稳定性;2)利用电控位移台改变成像相机位置和照明光源位置,对视网膜内核层的微细血管进行纵向定位;3)对视网膜微细血管成像光路进行了优化设计,包括照明光源的光路设计、系统时序的设计等,讨论了系统焦深对微细血管成像的影响。设计并搭建了视网膜自适应光学系统,对视网膜内核层中的微细血管进行成像,获得了直径小于10μm的微细血管图像,并且通过图像处理方法将微细血管图像的对比度提高到0.35。为解决自适应成像视场小、视网膜检测覆盖率低的问题,设计了多视场自适应光学视网膜成像系统;计算了液晶波前校正器的像素数并设计了多视场在液晶波前校正器上的排列方式;设计了多视场哈特曼波前探测器,并利用两个视场进行了模拟验证,确定了多视场哈特曼波前探测器的精度可以满足实验要求。本研究将推动视网膜微细血管成像早日应用于临床诊断。
[Abstract]:Endocrine diseases, such as diabetes, hypertension and so on in the early stage in the retinal microvascular diameter below 10 渭 m appear on the hemangioma, cotton spots and other symptoms. Imaging of retinal microvessels can make early diagnosis of endocrine lesions in time, but when observing retina, we must dilate pupil and introduce strong aberration of human eyes. Make the ophthalmoscope used in medical clinic only see the diameter 15? Only by combining with adaptive optics and real time detecting and correcting the aberration of human eyes can we get a high resolution imaging effect of 3 渭 m. The retina is composed of 10 layers of translucent tissue with a diameter of less than 10 渭 m, which is located in the nuclear layer of tens of microns thick, and the parameters of the human eye structure are different. In addition, the low contrast of microvascular imaging and the small adaptive imaging field of view are also the problems that need to be solved. This paper aims at the optical properties of human eyes. An innovative design of adaptive imaging optical path system is presented, and a method of locating and imaging the fine vessels in the inner kernel layer is proposed, which takes the visual cell layer as the reference position. The common area of microvascular layer in different human eyes was counted. By using the model eye to simulate the human eye, the relationship between the effective focal length of the human eye and the length of the human eye axis is obtained, and the location of the image plane of the kernel layer can be accurately calculated. The problem of different structure parameters of human eyes was solved. Experiment 1: 1 of microvascular localization was designed to locate the retina laterally using the method of visual standard guidance. The accuracy and stability of human eye staring can be maintained by determining that the visual marker is located at the 1D position of the eye. 2) changing the position of imaging camera and illuminating light source by using electronic control displacement table to locate the fine vessels in the inner layer of retina longitudinally; 3) the optical path of retinal microvascular imaging is optimized, including the design of illumination light source, the design of system timing and so on. The effect of system focal depth on microvascular imaging is discussed. A retinal adaptive optical system is designed and built to image the microvessels in the inner layer of the retina. The microvascular image with diameter less than 10 渭 m was obtained, and the contrast of the image was raised to 0.35 by image processing. In order to solve the problem of small field of view in adaptive imaging. In order to solve the problem of low retinal detection coverage, a multi-field adaptive optical retinal imaging system is designed. The number of pixels of the liquid crystal wavefront corrector is calculated and the arrangement of multi-view field on the liquid crystal wavefront corrector is designed. A multi-field Hartman wavefront detector is designed and simulated with two fields of view. The accuracy of the multi-field Hartmann wavefront detector is determined to meet the experimental requirements. This study will promote the application of retinal microvascular imaging in clinical diagnosis at an early date.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O439

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