液晶自适应光学视网膜校正成像技术研究

为了实现对人眼视网膜的高分辨率成像，解决偏振能量损失、成像视场小和普适性差等问题，对液晶自适应光学技术及其在人眼视网膜成像中的应用进行了研究。通过开环光路的设计方案，避免了闭环液晶自适应系统的偏振光能量损失; 在光路中加入可变视场光阑，利用小视场照明进行波前探测、大视场照明进行像差校正和成像的方法扩大了成像视场; 使用脉冲光照明的方案减小曝光量; 通过偏振光照明提高能量利用率、等效无穷远视标配合补偿镜以及改进后的视标提高盯视稳定性等一系列方法，提高系统普适性。校正后成像的清晰度和对比度获得了明显提高; 高分辨率眼底成像视场直径从200 μm扩大到500 μm; 曝光量减小到原来的1/2~1/3; 对前期难以获得清晰成像的样本，取得了效果良好的视网膜视觉细胞自适应图像。

Abstract

In order to realize high resolution retinal imaging, the technique of Liquid Crystal Adaptive Optics(LC-AO) and its utilize in retinal imaging is under investigation. Problems are settled in the research such as energy loss by polarization, limitation on field of view(FOV) and universality of LC-AO system in retinal imaging. Open-loop adaptive optics system is introduced to avoid the energy loss by polarization in closed-loop system. View field of imaging system is expanded by adhibition of an alterable diaphragm. Exposure ratio is reduced by a pulsed light source. Illumination is polarized to increase energy efficiency. Trial lens and dynamic, advanced target at infinite are used to increase the stability of pupil and reduce the impact of individual differences on human-eyes. Definition and contrast of images after correction are remarkably increased. FOV is enhanced from 200 μm to 500 μm. Exposure ratio is reduced to 1/2~1/3. High definition images are taken from samples with low resolution before. Most problems of LC-AO system for high resolution retinal imaging are settled.

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郑贤良, 刘瑞雪, 夏明亮, 曹召良, 宣丽. 液晶自适应光学视网膜校正成像技术研究[J]. 中国光学, 2014, 7(1): 98. ZHENG Xian-liang, LIU Rui-xue, XIA Ming-liang, CAO Zhao-liang, XUAN Li. Retinal correction imaging system based on liquid crystal adaptive optics[J]. Chinese Optics, 2014, 7(1): 98.

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