IOE OpenIR  > 光电技术研究所博硕士论文
人眼色像差测量技术研究
邓杨春
学位类型博士
导师张雨东 ; 戴云
2018-05-04
学位授予单位中国科学院研究生院
学位授予地点北京
关键词人眼色差 同时测量 双通技术 自适应光学 哈特曼波前探测技术
摘要

人眼中同时存在着单色像差和色差。成熟的哈特曼波前传感技术和自适应光学技术,使得单色像差得到了很好的测量与校正,这些技术被广泛应用于眼底成像和视光学的研究中。在单色像差被校正后,人眼色差成为了影响多波长眼底成像分辨率与人工晶体眼视功能的主要因素。实时、准确地评价人眼色差,对提高多波长眼底成像精度和提高人工晶体眼视功能具有重要的价值。当前,基于自适应光学技术客观评价人眼色差的方法已在国际上发表,其中轴向色差的测量已经实现了临床应用。但是,目前色差的研究只针对单一轴向色差或者横向色差进行,并多为分时测量,而不考虑眼球运动带来的影响;另外,用于测量单色像差的人眼双通系统,其双通特性是否能够很好地适用于人眼色差的测量都需要进一步的研究。因此,实现两种人眼色差客观、同时地测量具有重要意义。

在这一背景下,结合前人的研究成果,本文主要进行了以下工作内容的研究:

(1)研究人眼双通系统的双通特性是否适用于色差测量的研究。横向色差是通过不同波长的奇像差获得的,但在早期的研究中,认为两个通道的奇像差存在抵消现象,因此有必要重新研究双通系统的特性。本文建立全新的模拟眼模型进行实验,验证双通系统在波前测量时,是否存在人眼奇像差抵消的现象。采用典型人眼双通系统——哈特曼波前像差测量装置进行实验,测量出入瞳不匹配情况的典型奇像差——彗差。实验表明,双通系统中,人眼奇像差在出入瞳直径相等时可测,且人眼奇像差与出入瞳直径差异无关,最终得到人眼奇像差在双通系统中不抵消的结论。结果表明人眼双通系统适用于人眼色差的研究。

(2)人眼色差测量原理性实验。设计一套可同时测量人眼轴向色差与横向色差的系统,该系统采用两台哈特曼波前传感器实现两波长像差的同时测量,最终实现两种色差的同时测量。首先,分别测量红光(639nm)与红外光(786nm),绿光(532nm)与红外光(786nm)在模拟眼中的色差。不同波长的波前信息转化为泽尼克(Zernike)多项式,采用泽尼克的倾斜项计算横向色差、离焦项计算轴向色差。在模拟眼实验中,横向色差随着模拟眼测量位置的偏移而线性变化;但是,横向色差随波长变化并不是线性的,在短波段处的变化比长波段处更为陡峭。然后,测量人眼在视轴上的色差信息,轴向色差平均值为0.34D,水平方向横向色差平均值为2.496 arcmin,竖直方向横向色差平均值为0.458arcmin,其中轴向色差个体差异较小,横向色差个体差异较大。最后,色差测量结果与前人的色差测量结果进行比较,验证了本文提出的色差测量方法的可行性。

(3)基于自适应光学技术的全视场色差测量。考虑消除单色像差对色差测量的影响,引入Badal调焦技术和自适应光学技术一同校正单色像差,能够很好地将单色像差校正到残余像差RMS小于0.29μm。在此基础上,通过不同波长眼底PSF图像质心偏差量计算横向色差,并通过人眼瞳面波前的泽尼克离焦项计算轴向色差,评估从鼻侧到颞测,以视轴为中轴,-10°到10°视场之间的色差情况。五名被试者水平横向色差随视场线性变化的平均速率为0.162 arcmin/degrees。与前人的结果对比,说明横向色差变化与波长之间不存在线性关系。进一步说明,横向色差随视场变化的速率在短波段中要大于在长波段中的变化速率。轴向色差随视场变化有所增大或减小;在接近眼轴位置(5°颞侧附近)轴向色差最小,平均值为0.37 D,随眼轴与测量轴偏离越大,轴向色差越大。

(4)人眼色差测量系统误差分析。分析实验系统中,探测光路上的眼底相机采集PSF图像的误差来源与哈特曼波前传感器探测波前的误差来源。评价人眼色差测量系统测量人眼色差的精度与重复性。

其他摘要

Optic errors of the human eye are divided into monochromatic and chromatic aberrations. Hartmann wavefront sensing technique and adaptive optics technology make monochromatic aberration well measured and corrected. These techniques have been widely used in high-resolution retinal imaging and vision studies. After the monochromatic aberration corrected, the chromatic aberration of human eye has become the main factor that affects the resolution of multi-wavelength fundus imaging and the visual performance of intraocular lens. It is of great value to evaluate the chromatic aberrations of human eye in real time for improving the accuracy of multi-wavelength fundus imaging and the visual performance of intraocular lens. Nowadays, the method of objectively evaluating human eye chromatic aberration based on adaptive optics technology has been published, in which the measurement of longitudinal chromatic aberration has achieved clinical application. However, the current study of chromatic aberration only focuses on only longitudinal chromatic aberration (or axial chromatic aberration, LCA) or transverse chromatic aberration (or lateral chromatic aberration, TCA); most of methods are time-sharing measurements without considering the influence of eye movement. In addition, whether the double-pass system, which is employed to measure monochromatic aberration, can be well applied to the measurement of human eye chromatic aberration needs further study. Therefore, it is of great significance to realize the objective and simultaneous measurement of two kinds of human eye chromatic aberration.

In this background, combined with the achievements of previous research, this paper mainly carried out the following work:

(1) To study whether double-pass system is able for the measurement of human eye chromatic aberration. TCA is obtained by the odd aberration of different wavelengths, but in the early research, the odd aberration in the two passes had cancellation; so it is necessary to re-study the principle of the double-pass system. In this paper, a new model eye is developed to verify whether the double-pass system is able to measure the odd aberration. A typical human eye double-pass system-Hartmann wavefront aberration measurement system was developed to measure the typical odd aberration-coma. The experiment showed that in the double-pass system, the odd aberration of human eye could be measured when the entrance pupil and exit pupil size were equal. Human eye’s odd aberration was not related to the size of entrance pupil and exit pupil. Besides, double-pass system did not cancel human eye’s odd aberration. The results show that the human eye double-pass system is suitable for the study of human eye chromatic aberration.

(2) The principle experiment of human eye chromatic aberration measurement. A system for simultaneous measurement of LCA and TCA in human eyes was developed. Two Hartmann wavefront sensors were developed to simultaneously measure wavefront of two wavelengths. First, the chromatic aberration between red light (639nm) and infrared light (786nm), green light (532nm) and infrared light (786nm) in model eye was measured respectively. The chromatic wavefronts were converted into Zernike polynomials. The Zernike tilt coefficient (first-term) was used to calculate TCA along the x-direction, while the Zernike defocus coefficient (forth-term) was used to calculate LCA. In the model eye experiment, TCA changed linearly with the displacement of the measurement position of the model eye. However, the variation of TCA with wavelength was not linear, and TCA change with eccentricity in the short spectral range was faster than the long spectral range. In addition, human eye chromatic aberration in central field of view was measured; the average value of LCA was 0.34 D, the horizontal TCA was 2.496 arcmin, and the vertical TCA was 0.458 arcmin. The individual difference of LCA was insignificant. However, TCA significantly varied among the subjects, even between the eyes of the same subject. Finally, the results of chromatic aberration measurement were compared with previous studies, which verified the feasibility of the chromatic aberration measurement method proposed in this paper.

(3) Chromatic aberration measurement based on adaptive optics technology across the visual field. Considering the influence of monochromatic aberration, the Badal focusing technology and adaptive optics technology were introduced to correct monochromatic aberration together. In the case of monochromatic aberration correction, the residual aberration RMS was less than 0.29μm. TCA of human eye was obtained by deviation of point-spread function (PSF) images and LCA was calculated from Zernike defocus across -10° to 10°field of view. The change of TCA with eccentricity was 0.162 arcmin/degree. Compared with the previous studies, TCA was not linear with the change of wavelengths. It further showed that the change of TCA with eccentricity was faster in the short band than that in the long band. LCA increased or decreased with the change of the view field. Near the eye axis (5° in temporal side), LCA was the smallest; the average LCA value was 0.37 D. LCA increases with the eye axis deviates from the measuring axis.

(4) To evaluate the measurement error of human eye chromatic aberration measurement system. The error sources of PSF collection in fundus camera and wavefront collection in Hartman wavefront sensor were analyzed. The accuracy and repeatability of human eye chromatic aberration measurement system was evaluated.

学科领域应用光学
语种中文
文献类型学位论文
条目标识符http://ir.ioe.ac.cn/handle/181551/8291
专题光电技术研究所博硕士论文
作者单位1.中国科学院光电技术研究所
2.中国科学院大学
推荐引用方式
GB/T 7714
邓杨春. 人眼色像差测量技术研究[D]. 北京. 中国科学院研究生院,2018.
条目包含的文件
文件名称/大小 文献类型 版本类型 开放类型 使用许可
人眼色像差测量技术研究-终稿.pdf(6751KB)学位论文 开放获取CC BY-NC-SA请求全文
个性服务
推荐该条目
保存到收藏夹
查看访问统计
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[邓杨春]的文章
百度学术
百度学术中相似的文章
[邓杨春]的文章
必应学术
必应学术中相似的文章
[邓杨春]的文章
相关权益政策
暂无数据
收藏/分享
所有评论 (0)
暂无评论
 

除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。