用于全眼段成像和视轴参数测量的四焦点开关光学相干断层扫描

Four-focus Switch Optical Coherence Tomography for Whole Eye Segment Imaging and Visual Axis Parameters Measurement

本文演示了四焦点开关傅里叶域光学相干断层扫描系统用于全眼段成像和体内视轴参数(VAP)测量的可行性.使用包括不同厚度平行玻璃板的两个同步转盘来将探测光束的焦点位置从角膜以及晶状体的前部和后部切换到视网膜.该过程同时增加了参考光束的深度范围.这种多级聚焦的方法可以使探测光束完全聚焦在人眼的每个部分.初步实验表明,该方法可以实现全眼段成像和包括中央角膜厚度、前房深度、晶状体厚度和轴长在内的VAP测量.

We demonstrate the feasibility of a four-focus switch Fourier-domain optical coherence tomography system for whole eye segment imaging, and in vivo visual axis parameter(VAP) measurement. In this study, we use two rotating disks to switch the focus position synchronously, to expand the detection depth range. Three parallel glass plates of different thicknesses are placed on a rotating disk along the path of the detection beam, so as to switch the focus position of the probing beam from the cornea, the anterior and posterior of the lens to the retina. On the other synchronously rotating disk, the light path of the reference arm can simultaneously extend the detecting optical path to match the probing beam. This multistage focusing method can make the probing beam completely focused on each segment of the human eye during the course of signal collection. Subsequently, we measured VAP several times, and the results show that our four-focus switch FD-OCT system exhibits good repeatability. In conclusion, we prove theoretically and experimentally that the proposed four-focus switched FD-OCT system can realize whole eye segment imaging and VAP measurement, including central corneal thickness, anterior chamber depth, lens thickness, and axial length. Our method will be beneficial for measurements in ophthalmology.