Analysis of Pulsatile Retinal Movements by Spectral-Domain Low-Coherence Interferometry: Influence of Age and Glaucoma on the Pulse Wave

Recent studies have shown that ocular hemodynamics and eye tissue biomechanical properties play an important role in the pathophysiology of glaucoma. Nevertheless, better, non-invasive methods to assess these characteristics in vivo are essential for a thorough understanding of degenerative mechanisms. Here, we propose to measure ocular tissue movements induced by cardiac pulsations and study the ocular pulse waveform as an indicator of tissue compliance. Using a novel, low-cost and non-invasive device based on spectral-domain low coherence interferometry (SD-LCI), we demonstrate the potential of this technique to differentiate ocular hemodynamic and biomechanical properties. We measured the axial movement of the retina driven by the pulsatile ocular blood flow in 11 young healthy individuals, 12 older healthy individuals and 15 older treated glaucoma patients using our custom-made SD-OCT apparatus. The cardiac pulse was simultaneously measured through the use of an oximeter to allow comparison. Spectral components up to the second harmonic were obtained and analyzed. For the different cohorts, we computed a few parameters that characterize the three groups of individuals by analyzing the movement of the retinal tissue at two locations, using this simple, low-cost interferometric device. Our pilot study indicates that spectral analysis of the fundus pulsation has potential for the study of ocular biomechanical and vascular properties, as well as for the study of ocular disease.

近期研究表明，眼血流动力学与眼组织生物力学特性在青光眼的病理生理进程中发挥着关键作用。然而，若要全面阐明青光眼的退行性发病机制，亟需开发更优的非侵入性体内评估方法。本研究拟测量心脏搏动诱导的眼组织位移，并将眼脉冲波形作为组织顺应性的表征指标开展相关研究。我们依托一种基于光谱域低相干干涉术（spectral-domain low coherence interferometry, SD-LCI）的新型低成本非侵入式设备，验证了该技术区分眼血流动力学与生物力学特性的潜力。使用本团队定制的光谱域光学相干断层扫描（SD-OCT）设备，我们对11名年轻健康受试者、12名老年健康受试者以及15名接受治疗的老年青光眼患者的搏动性眼血流量驱动的视网膜轴向位移进行了测量；同时通过血氧仪同步采集心脏脉搏信号以用于对照分析。我们提取并分析了涵盖至二次谐波频段的频谱分量，并通过分析两个视网膜位点的组织位移，计算出可区分三类受试者群体的多项特征参数。本预实验结果显示，眼底搏动频谱分析技术在眼生物力学与血管特性研究以及眼部疾病研究领域均具备应用潜力。