自适应光学相干层析在视网膜高分辨成像中的应用

Application of adaptive optics coherence tomography in retinal high resolution imaging

视网膜光学相干层析(OCT)技术利用外部低相干光源照射人眼眼底,并将人眼眼底散射信号进行干涉成像,获得人眼视网膜的断层图像信息,以实现人眼视网膜无创、实时、在体的光学活检。传统光学相干层析在视网膜成像时的轴向分辨率可达3μm以上,但由于人眼个体差异和不可避免的像差限制了视网膜OCT的横向分辨率,只能达到约15~20μm。而自适应光学作为一项波前校正的先进技术,可以校正OCT色差以及人眼有限视场和眼球运动导致的像差,将OCT横向分辨率提高到低于2μm,以实现视网膜细胞及微细血管近衍射极限成像,及时发现患者眼底存在的早期病变。在介绍自适应光学和视网膜光学相干层析的技术特点基础上,对自适应光学在视网膜光学相干层析成像应用的国内外发展现状进行了论述,总结了自适应光学OCT视网膜高分辨成像在宽带光源色差校正、眼球运动伪影减少、自适应光学视场扩大和波前传感与校正系统简化的关键技术和未来发展趋势,以实现大视场、高效率、高灵敏度、高分辨率的高速人眼视网膜成像,为未来自适应光学OCT视网膜成像技术的研究和应用提供参考和借鉴。

Retinal optical coherence tomography(OCT) technology uses external low coherence light source to irradiate the fundus of the human eye, and interfere scattered signals of the fundus of the human eye to obtain the sectional image information of the human retina, so as to realize the non-invasive, real-time and in vivo optical biopsy of the human retina. The axial resolution of traditional optical coherence tomography in retinal imaging can reach more than 3 μm, but the transverse resolution of OCT can only reach about 15-20 μm due to individual differences and inevitable aberrations. Adaptive optics, as an advanced technology of wavefront correction, can correct OCT chromatic aberration and aberrations caused by limited field of view and eye movement, so as to improve the transverse resolution of OCT to less than 2 μm. Adaptive optics OCT can realize near diffraction limit imaging of retinal cells and microvessels to timely detect the early lesions in patients with fundus. Based on the introduction of the technical characteristics of adaptive optics and retinal optical coherence tomography, the development status of adaptive optics in retinal optical coherence tomography at home and abroad was reviewed,and the key technologies and future development trends of adaptive optics OCT retinal high-resolution imaging in wide-band light source chromatic aberration correction, eye movement artifact reduction, adaptive optics field of view expansion and wavefront sensing and correction system simplification were summarized, so as to realize high-speed retinal imaging with large field of view, high efficiency, high sensitivity and high resolution, and provide reference for the future research and application of adaptive optics OCT retinal imaging technology.