提高眼底自适应光学成像系统的普适性设计

Research on improving the universality of adaptive optical retinal imaging system

自适应光学技术被广泛应用于人眼像差的校正,从而实现眼底细胞和微血管进行高分辨率成像。传统自适应光学系统受夏克哈特曼波前探测器的动态范围限制,只对部分人群适用,无法对高屈光不正人群进行眼底高分辨率成像。为了提高眼底自适应光学成像系统普适性,本文设计了一种基于音圈变形镜高分辨率眼底自适应光学成像系统:引入Badal调焦系统,能够对人眼屈光度在-8~8 D的眼底进行高分辨率成像;用轴锥透镜组代替传统的环形光阑,控制正、负轴锥透镜间距可以调节环形光内径,以适应不同人眼的角膜,同时避免角膜反射的杂光;通过视标引导实现大视场成像。仿真结果表明,照明子系统在眼底视网膜照度分布均匀;在设定的公差范围内,至少有90%的MTF值在25 lp/mm达到0.21(对应视网膜上4μm)。在实验室搭建了相应的光路,对大畸变的模拟人眼进行了成像,获得了较好的成像效果。

Adaptive optics is widely used to correct aberrations in the human eye,achieving high-resolution imaging of fundus cells and microvessels.Traditional adaptive optics systems are limited by the dynamic range of the Shack Hartmann wavefront detector and are only suitable for some people,and cannot perform fundus high-resolution imaging in people with high refractive errors.In order to improve the universality of fundus adaptive optical imaging system,this paper designs a high-resolution fundus adaptive optical imaging system based on voice coil deformation mirror.The introduction of the Badal focusing system can perform highresolution imaging of the fundus with the diopter of the human eye between-8~8 D.In this system,the traditional annular diaphragm is replaced with an adjustable axial cone lens set,the spacing of positive and negative axonal cone lenses are controlled to adjust the inner diameter of annular light in order to adapt the cornea of different eyes,and avoid stray light reflected by the cornea.Large field of view imaging is realized through visual beacon guidance.The simulation results show that the illumination subsystem has a uniform distribution of retinal illumination in the fundus.Within the set tolerance,at least 90%of the MTF values reach 0.21 at 25 lp/mm(corresponding to 4μm on the retina).The corresponding optical path was built in the laboratory,and the simulated human eye with large distortion was imaged,and a good imaging effect was obtained.