Zhang Tingwei, Kho Aaron M, Srinivasan Vivek J
Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA.
Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, 95817, USA.
Biomed Opt Express. 2019 May 21;10(6):2918-2931. doi: 10.1364/BOE.10.002918. eCollection 2019 Jun 1.
Visible light optical coherence tomography (OCT) theoretically provides finer axial resolution than near-infrared OCT for a given wavelength bandwidth. To realize this potential in the human retina , the unique technical challenges of visible light OCT must be addressed. We introduce three advances to further the performance of visible light OCT in the human retina. First, we incorporate a grating light valve spatial light modulator (GLV-SLM) spectral shaping stage to modify the source spectrum. This enables comfortable subject alignment with a red light spectrum, and image acquisition with a broad "white light" spectrum, shaped to minimize sidelobes. Second, we develop a novel, Fourier transform-free, software axial motion tracking algorithm with fast, magnetically actuated stage to maintain near-optimal axial resolution and sensitivity in the presence of eye motion. Third, we implement spatially dependent numerical dispersion compensation for the first time in the human eye . human retinal OCT images clearly show that the inner plexiform layer consists of 3 hyper-reflective bands and 2 hypo-reflective bands, corresponding with the standard anatomical division of the IPL. Wavelength-dependent images of the outer retina suggest that, beyond merely improving the axial resolution, shorter wavelength visible light may also provide unique advantages for visualizing Bruch's membrane.
可见光光学相干断层扫描（OCT）理论上在给定波长带宽下比近红外OCT具有更高的轴向分辨率。为了在人类视网膜中实现这一潜力，必须解决可见光OCT独特的技术挑战。我们介绍三项进展，以进一步提升可见光OCT在人类视网膜中的性能。首先，我们纳入一个光栅光阀空间光调制器（GLV-SLM）光谱整形阶段来修改光源光谱。这使得受试者能舒适地与红光光谱对齐，并使用经过整形以最小化旁瓣的宽“白光”光谱进行图像采集。其次，我们开发了一种新颖的、无需傅里叶变换的软件轴向运动跟踪算法，并配备快速磁驱动平台，以在存在眼球运动的情况下保持近乎最佳的轴向分辨率和灵敏度。第三，我们首次在人眼中实现了空间相关的数值色散补偿。人眼视网膜OCT图像清楚地表明，内网状层由3个高反射带和2个低反射带组成，与IPL的标准解剖划分相对应。视网膜外层的波长相关图像表明，除了提高轴向分辨率之外，更短波长的可见光在可视化布鲁赫膜方面可能还具有独特优势。
