Measurement of Ocular Fundus Pulsation in Healthy Subjects Using a Novel Fourier-Domain Optical Coherence Tomography

PURPOSE: Anomalies in the pulsatility of the eye have been associated with many types of ocular pathology. Estimation of ocular pulsatility is usually obtained by measuring the variation in the intraocular pressure using tonometry-based instruments. In this work, the authors present and demonstrate the applicability of a novel and noninvasive Fourier-domain optical coherence tomography (FD-OCT) system to measure pulsatile ocular tissue movements. METHODS: The authors simultaneously measured the longitudinal movement of the cornea and the retina driven by the cardiac cycle in 21 healthy volunteers using their custom-made FD-OCT. They calculated the corresponding fundus pulse amplitude (FPA), which is the variation in the distance between the cornea and the retina. RESULTS: It was found that in young, healthy subjects, the cornea and the retina move axially during the cardiac cycle, with almost equal amplitude but with a phase difference ranging between 1° and 20°. The measured FPA was found to be mostly due to the relative phase difference between corneal and retinal movements, and frequency analysis revealed the presence of the harmonics of heartbeat. The root-mean-square values for cornea, retina, and FPA movements were found to be 28 ± 9 μm, 29 ± 9 μm, and 4 ± 2 μm, respectively. The dominant frequency component in corneal and retinal movement was found to be the second harmonic of the heartbeat. CONCLUSIONS: The technique described here is useful for a precise description of FPA and the movement of ocular tissues. Further investigations and technical improvements will be beneficial for understanding the role of choroidal pulsation in the pathophysiology of ocular diseases.