Anterior Eye Imaging with Optical Coherence Tomography
Anterior Eye Imaging with Optical Coherence Tomography
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DOI：
10.1007/978-3-540-77550-8_31
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发表时间：
2008-01-01
期刊：
影响因子：
--
通讯作者：
Tang, M.
中科院分区：
文献类型：
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作者：
Huang, D.;Li, Y.;Tang, M.
光学相干断层扫描[1]（OCT）首先在临床上用于视网膜成像。[2]Carl Zeiss Meditec，Inc.（都柏林，CA）已经引入了三代视网膜OCT扫描仪：OCT 1、OCT 2和OCT 3（Stratus）。OCT在临床视网膜成像中的应用已为大多数眼科医生所熟悉。毫不奇怪，最早的角膜OCT研究[3-7]使用了市售的视网膜扫描仪。然而，有几个原因，为什么视网膜扫描仪是不理想的角膜和眼前节成像。1。目前的视网膜OCT扫描仪太慢。视网膜OCT的当前临床标准，Zeiss Stratus系统，每秒采集400次轴向扫描。虽然这对于获得角膜上的点测量是足够的，但是对于映射角膜或测量前房的宽度来说太慢了。在图31.1.2所示的Stratus OCT图像中，角膜轮廓的运动误差很明显。视网膜OCT系统的波长约为830 nm。这种非常近的红外波长在不透明的组织（如巩膜）中遇到严重的散射损失。在该波长下的光学相干断层扫描不能可视化角结构，例如scierai spur和角凹，这是前房生物测量和窄角青光眼诊断的重要标志。
Optical coherence tomography [1] (OCT) was first used clinically for retinal imaging. [2] Carl Zeiss Meditec, Inc. (Dublin, CA) has introduced three generations of retinal OCT scanners: OCT1, OCT2, and OCT3 (Stratus). Most ophthalmologists are now familiar with the applications of OCT in clinical retinal imaging. Not surprisingly, the earliest corneal OCT studies [3–7] used a commercially available retinal scanner. However, there are several reasons why retinal scanners are not ideal for corneal and anterior segment imaging.1.Current retinal OCT scanners are too slow. The current clinical standard for retinal OCT, the Zeiss Stratus system, acquires 400 axial scans per second. While this is adequate for obtaining a spot measurement on the cornea, it is far too slow for mapping the cornea or measuring the width of the anterior chamber. The motion error in the contour of the cornea is obvious in the Stratus OCT image shown in Fig. 31.1.2.The wavelength of retinal OCT systems is approximately 830 nm. This very near infrared wavelength encounters heavy scattering loss in opaque tissues such as the sciera. Optical coherence tomography at this wavelength cannot visualize angle structures such as the scierai spur and angle recess, important landmarks for anterior chamber biometry and narrow angle glaucoma diagnosis.