Chong Shau Poh, Zhang Tingwei, Kho Aaron, Bernucci Marcel T, Dubra Alfredo, Srinivasan Vivek J
Biomedical Engineering Department, University of California Davis, Davis, CA 95616, USA.
Equal contributions.
Biomed Opt Express. 2018 Mar 5;9(4):1477-1491. doi: 10.1364/BOE.9.001477. eCollection 2018 Apr 1.
Chromatic aberrations are an important design consideration in high resolution, high bandwidth, refractive imaging systems that use visible light. Here, we present a fiber-based spectral/Fourier domain, visible light OCT ophthalmoscope corrected for the average longitudinal chromatic aberration (LCA) of the human eye. Analysis of complex speckles from retinal images showed that achromatization resulted in a speckle autocorrelation function that was ~20% narrower in the axial direction, but unchanged in the transverse direction. In images from the improved, achromatized system, the separation between Bruch's membrane (BM), the retinal pigment epithelium (RPE), and the outer segment tips clearly emerged across the entire 6.5 mm field-of-view, enabling segmentation and morphometry of BM and the RPE in a human subject. Finally, cross-sectional images depicted distinct inner retinal layers with high resolution. Thus, with chromatic aberration compensation, visible light OCT can achieve volume resolutions and retinal image quality that matches or exceeds ultrahigh resolution near-infrared OCT systems with no monochromatic aberration compensation.
色差是使用可见光的高分辨率、高带宽折射成像系统中的一个重要设计考量因素。在此，我们展示了一种基于光纤的光谱/傅里叶域可见光光学相干断层扫描（OCT）检眼镜，其针对人眼的平均纵向色差（LCA）进行了校正。对视网膜图像中的复杂散斑进行分析表明，消色差处理使得散斑自相关函数在轴向方向变窄了约20%，但在横向方向保持不变。在改进后的消色差系统所获取的图像中，布鲁赫膜（BM）、视网膜色素上皮（RPE）和外段尖端之间的分隔在整个6.5毫米视场中清晰显现，从而能够对人体受试者的BM和RPE进行分割和形态测量。最后，横截面图像以高分辨率描绘了不同的视网膜内层。因此，通过色差补偿，可见光OCT能够实现与无单色像差补偿的超高分辨率近红外OCT系统相匹配或超越其的体素分辨率和视网膜图像质量。
