Zhang Xiangyang, Hu Jianming, Knighton Robert W, Huang Xiang-Run, Puliafito Carmen A, Jiao Shuliang
Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
Opt Express. 2011 Sep 26;19(20):19653-9. doi: 10.1364/OE.19.019653.
The ultimate goal of the study is to provide an imaging tool to detect the earliest signs of glaucoma before clinically visible damage occurs to the retinal nerve fiber layer (RNFL). Studies have shown that the optical reflectance of the damaged RNFL at short wavelength (<560 nm) is reduced much more than that at long wavelength, which provides spectral contrast for imaging the earliest damage to the RNFL. To image the spectral contrast we built a dual-band spectral-domain optical coherence tomography (SD-OCT) centered at 808 nm (NIR) and 415 nm (VIS). The light at the two bands was provided by the fundamental and frequency-doubled outputs of a broadband Ti:Sapphire laser. The depth resolution of the NIR and VIS OCT systems are 4.7 µm and 12.2 µm in the air, respectively. The system was applied to imaging the rat retina in vivo. Significantly different appearances between the OCT cross sectional images at the two bands were observed. The ratio of the light reflected from the RNFL over that reflected from the entire retina at the two bands were quantitatively compared. The experimental results showed that the dual-band OCT system is feasible for imaging the spectral contrasts of the RNFL.
该研究的最终目标是提供一种成像工具，以便在视网膜神经纤维层（RNFL）出现临床可见损伤之前检测出青光眼的最早迹象。研究表明，受损RNFL在短波长（<560 nm）下的光学反射率比在长波长下降低得更多，这为成像RNFL的最早损伤提供了光谱对比度。为了对光谱对比度进行成像，我们构建了一个以808 nm（近红外）和415 nm（可见光）为中心的双波段光谱域光学相干断层扫描（SD-OCT）。两个波段的光由宽带钛宝石激光器的基频输出和倍频输出提供。近红外和可见光OCT系统在空气中的深度分辨率分别为4.7 µm和12.2 µm。该系统被应用于对大鼠视网膜进行活体成像。观察到两个波段的OCT横截面图像之间存在明显不同的外观。定量比较了两个波段下RNFL反射光与整个视网膜反射光的比率。实验结果表明，双波段OCT系统对于成像RNFL的光谱对比度是可行的。
