Pircher M, Götzinger E, Hitzenberger C K
Medical University of Vienna, Center for Biomedical Engineering and Physics, Vienna, Austria.
J Biomed Opt. 2006 Sep-Oct;11(5):054013. doi: 10.1117/1.2358960.
Imaging the human retina still represents the main field of application of optical coherence tomography (OCT). A major advantage of OCT is the decoupling of depth resolution (given by the coherence length of the light source) and transverse resolution (given by the focal spot size). This enables images of the retina with high depth resolution. On the other hand, in most OCT systems, a limited transverse resolution has been accepted to provide a sufficiently large (approximately 1 mm) depth of focus. However, to obtain images with high transverse resolution throughout the whole depth of the retina (especially in the nerve head region) a tracking of coherence gate and focus position (dynamic focus) is essential. This study realizes a dynamic focus in a time domain transversal (en face) scanning system for retinal imaging. We show that maintenance of a transverse resolution of approximately 4.4 microm can be achieved over an optical depth of 1 mm in a model eye and apply our method to imaging the human retina in vivo.
对人类视网膜进行成像仍然是光学相干断层扫描（OCT）的主要应用领域。OCT的一个主要优势是深度分辨率（由光源的相干长度决定）和横向分辨率（由焦斑尺寸决定）的解耦。这使得能够获得具有高深度分辨率的视网膜图像。另一方面，在大多数OCT系统中，为了提供足够大（约1毫米）的焦深，横向分辨率受到限制。然而，要在视网膜的整个深度范围内（尤其是在视乳头区域）获得高横向分辨率的图像，跟踪相干门和焦点位置（动态聚焦）至关重要。本研究在用于视网膜成像的时域横向（正面）扫描系统中实现了动态聚焦。我们表明，在模型眼中，在1毫米的光学深度上可以实现约4.4微米的横向分辨率的维持，并将我们的方法应用于体内人类视网膜成像。
