人眼波前像差测量与矫正的研究

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3.0 赵德峰 2024-11-19 5 4 7.7MB 106 页 15积分

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摘要

眼睛是心灵的窗户，它的健康与否直接关系到每个个人的生活质量。然而，

同所有的实际光学系统一样，人眼不是一个完善的屈光系统，存在着各种像差，

其中不仅含有离焦、散光在内的各种低阶像差，还包括诸如三叶草，四叶草等在

内的高阶像差。长期以来，人们对人眼像差的测量和矫正主要集中在离焦、散光

等低阶像差项上，这一方面是因为统计意义上来讲，这类像差对于人类的视力影

响最大；另一方面，也是由于人类的镜片磨制技术只能矫正离焦、散光之类的低

阶像差。随着准分子激光手术的发展和普及，屈光手术已经得到了广泛的应用，

但患者术后的并发症也困扰着医生和病患。其中部分原因是由于对于高阶像差测

量的不完备导致角膜手术后患者眼的像差失控，深入理解和准确测量人眼高阶像

差对于有效控制角膜手术效果，提高病患生活质量无疑有着重要意义。

本文沿着上一届师兄的主客观结合的人眼像差测量平台思路出发，详细讨论

了这一人眼像差光学测量系统搭建过程中可能存在的误差，并对其进行了仔细地

定量分析和计算。根据计算结果，我们提出了基于客观测量数据的光学系统安装

与调节方案。在此基础之上，提出了优化了的主客观相结合的人眼像差测量光路，

分析并给出了眼瞳与 HSS 测量孔径不匹配情况下的像差还原代数方法。本文将以

如下线索展开：

从波前像差的基本概念出发，介绍波前像差的基本理论，并详细地分析了

Zernike 多项式各阶项对应表达式的含义；对 Hartmann-Shack 传感器测量人眼像差

的原理进行了详细分析，给出了 Hartmann-Shack 传感器可测量范围的公式和波前

重构的基本公式，计算了传感器的测量局限；分析了参考面上波前形状对最终测

量得到的被测波前结果的影响，计算并给出了基于客观的准直照明光束调节方法，

从而使得我们以较高的精度和可重复地获得了接近理想的参考波前；提出了应用

HSS 参与调节整个人眼测量光路的系统方法，解决了由于光学镜片制造公差、设

计波长与实际波长的不同所造成的包括离焦像差在内的各种透镜误差所可能带来

的系统安装误差，使得我们能够对的光学测量平台的搭建精度予以准确地判断，

并使得我们的测量结果具备信服，可靠，可重复的特点；引入了调节同轴度更高

的照明光束预调节系统，提高信噪比的同时解决了同轴度调节困难的问题；引入

了用于减小激光散斑影响的消散斑光路，对其消除散斑的可行性进行了实验研究；

提出了允许主观参与调节的主客观相结合的人眼像差测量系统；在实验部分，我

们分别用实验的方法研究了人眼主观调节对像差的改善、佩戴镜框眼镜对低阶和

高阶像差的改善以及应用可变形镜实时矫正人眼像差的可能性。进行较为全面的

实验分析与研究工作。

关键词：波前像差 Hartmann-Shack 传感器波前矫正准直系统

III

ABSTRACT

Eyes are the windows of soul. Our quality of lives largely depends on the health of

eyes. However, just like all the other kinds of optical systems in practice, aberrations, no

matter tiny or significant, are almost inevitable in human eyes. Including but not limited

to low order aberrations like defocus, astigmatism and higher order aberrations like

trifoil, quatrefoil as well. For a long period of time, human beings pay most of their

efforts in trying to measuring and correcting low order aberrations while making less

progress in dealing with higher order ones. Fact of this is partly because that, statisticly

speaking, low order aberrations impact the majority of people the most. On the other

hand, confined by the technique of lens manufacturing, we are only able to correcte low

order aberrations by using traditional glasses. Nowadays, with the development of

LASIK, corneal operations are being widely used. Unfortunately, post-operation

syndromes that take place in small percentage of patients trouble both doctors and

patients a lot. Part of the reasons result from the incapability of our technology to

adequately measure the essential higher order aberrations. Thereby, efforts on studying

and measuring ocular aberrations play very important role in controlling reliability of

corneal operation and improving patients' lives.

In this article, we discuss in details as to the probable causes of system errors

during our installment of ocular aberration measurement system and quantitively

analyze the impact brought by them. According to the calculation results, we propose

novel approaches to install and adjust optical system, which, is fully based on objective

information. After that, we optimised the design of combined ocular measurement

system. And we also deduce the algorithm method that could be used to trace back the

original aberrations on the condition that exit pupils of measured eyes are expanded to

match the entrance pupils of HSS. We will begin to introduce our ocular measurement

system in the following steps.

Firstly, we introduced the basic principle of wavefront aberration theory and

discuss the physical meaning of each Zernike term in details. After that, the

Hartmann-Shack principle was introduced in details. Secondly, we deduced the

equations that could be used to calculate the measureable range of HSS and the limits of

HSS used in our experiments are calculated in accordingly. When it comes to the most

important part of this article, the impacts of reference plane to the measurement results

are given, not only theoretically, but also experimentally. Given as a solution to solve

the problem brought by the necessity to acquire highly flat reference plane ，we

introduced a series of novel methods to adjust and minimize the system errors during

our setup of optical system and was thereby able to exactly judge the system errors,

which, makes our measurement results characterized as convincible, reliable and

repeatable. We also improved pre-adjusted illumination system, which significantly

improve the SNR performance while at the same time solve the difficulty in coaxial

adjustment. Also, we invented a device that could be used to remove the speckles of

laser inlumination and experiments were performed in accordingly. Finally, an ocular

measurement system which allow the users to take participate into adjustment while

their aberrations are being measured was successfully established and a series of

experiments were performed. We tried several ways to correctify the ocular aberrations,

including wearing glasses and using deformable mirror to correctify both high and low

order aberrations in realtime.

Key Word: Wavefront aberration, Hartmann-Shack Sensor, Wavefront

correction, Collimation system

中文摘要

ABSTRACT

第一章绪论 .....................................................................................................................1

§1.1 像差的概念 .......................................................................................................1

§1.2 人眼的像差及其影响因素 ...............................................................................2

§1.3 人眼像差测量技术及其发展 ..........................................................................2

§1.4 人眼像差的测量方法 .......................................................................................4

§1.4.1 人眼主观像差测量方法 .......................................................................4

§1.4.2 人眼客观像差测量方法 ........................................................................5

§1.4.3 主、客观测量法的异同 .......................................................................7

§1.5 国内外人眼像差测量、矫正发展动态 ..........................................................8

§1.6 本文所做的主要工作 ......................................................................................8

第二章人眼像差测量与 Hartmann-Shack 原理 ..........................................................11

§2.1 人眼的结构和屈光系统 .................................................................................11

§2.1.1 泪液膜 .................................................................................................11

§2.1.2 角（质）膜 .........................................................................................11

§2.1.3 虹膜与瞳孔 .........................................................................................12

§2.1.4 晶状体 .................................................................................................12

§2.1.5 玻璃体 .................................................................................................12

§2.1.6 视网膜 .................................................................................................12

§2.2 人眼像差的来源与屈光不正 .........................................................................12

§2.2.1 近视眼 .................................................................................................13

§2.2.2 远视眼 .................................................................................................14

§2.2.3 散光眼 .................................................................................................14

§2.3 波前像差理论 .................................................................................................15

§2.3.1 波前像差的展开与 Zernike 多项式的特点 ...................................... 16

§2.3.2 Zernike 多项式展开及其含义 ............................................................ 16

§2.4 Hartmann-Shack 波前传感器的数学原理 .................................................... 19

§2.5 Hartmann-Shack 波前传感器的量程与精度 ................................................ 20

§2.6 应用 Zernike 多项式的波前重构方法 .......................................................... 22

§2.7 本章小结 ........................................................................................................23

第三章人眼实时像差测量系统的构建 .......................................................................24

§3.1 人眼实时像差测量系统的基本结构 ............................................................24

§3.1.1 被测眼照明光路 .................................................................................24

§3.1.2 波前像差测量光路 .............................................................................25

§3.2 光路设计与参数配置 ....................................................................................26

§3.2.1 照明光源的选择 .................................................................................26

§3.2.2 人眼安全光照强度 .............................................................................28

§3.2.3 照明光路结构参数 .............................................................................30

§3.2.4 照明光束的获得 .................................................................................30

§3.2.5 像差矫正与测量光路参数配置 .........................................................31

§3.3 本章小结 ........................................................................................................43

第四章像差测量系统的误差分析与安装调试 ...........................................................45

§4.1 成像系统的理论误差——物理分辨率 .........................................................45

§4.2 准直照明光束的误差分析 ............................................................................48

§4.3 非准直入射光对波前测量的影响 ................................................................49

§4.3.1 非准直入射光对波前测量影响的实验验证 ......................................50

§4.3.2 实验结果 .............................................................................................50

§4.3.3 照明光路的改进：可调照明光路设计 ..............................................52

§4.4 眼波前演化给测量带来的影响 ....................................................................54

§4.5 像差测量光路安装误差分析 ........................................................................56

§4.6 HSS 在校准准直光路中的应用 .................................................................... 58

§4.6.1 球差的产生与消除 .............................................................................58

§4.6.2 彗差的产生与消除 .............................................................................58

§4.6.3 像散的产生与消除 ..............................................................................59

§4.6.4 光路的安装与调试 ..............................................................................59

§4.7 改进的人眼像差测量光路 ............................................................................64

§4.8 本章小结 .........................................................................................................66

第五章人眼波前像差的测量与矫正实验 ...................................................................67

§5.1Hartmann-Shack 采样点质量的提高 ............................................................. 67

§5.2 HSS 的有效量程测定 .................................................................................... 68

§5.3 入射光束直径对测量结果的影响 .................................................................70

§5.4 离焦补偿系统的有效性测试 ........................................................................73

§5.5 可变形镜对像差的主动补偿试验 ................................................................77

§5.6 可调照明系统的测试 ....................................................................................82

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摘要：

I摘要眼睛是心灵的窗户，它的健康与否直接关系到每个个人的生活质量。然而，同所有的实际光学系统一样，人眼不是一个完善的屈光系统，存在着各种像差，其中不仅含有离焦、散光在内的各种低阶像差，还包括诸如三叶草，四叶草等在内的高阶像差。长期以来，人们对人眼像差的测量和矫正主要集中在离焦、散光等低阶像差项上，这一方面是因为统计意义上来讲，这类像差对于人类的视力影响最大；另一方面，也是由于人类的镜片磨制技术只能矫正离焦、散光之类的低阶像差。随着准分子激光手术的发展和普及，屈光手术已经得到了广泛的应用，但患者术后的并发症也困扰着医生和病患。其中部分原因是由于对于高阶像差测量的不完备导致角膜手术后患者眼的像差失...

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