title: Measurement of ocular fundus pulsation in healthy subjects using a novel Fourier-domain optical coherence tomography.
abstract: OBJECTIVE
  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.
authors.affiliation: Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Québec, Canada.
authors.forename: Kanwarpal
authors.initials: K
authors.lastname: Singh
authors.forename: Carolyne
authors.initials: C
authors.lastname: Dion
authors.forename: Marcelo
authors.initials: M
authors.lastname: Wajszilber
authors.forename: Tsuneyuki
authors.initials: T
authors.lastname: Ozaki
authors.forename: Mark R
authors.initials: MR
authors.lastname: Lesk
authors.forename: Santiago
authors.initials: S
authors.lastname: Costantino
mesh_terms: D000328:Adult; D003315:Cornea / Q000098:blood supply* / Q000502:physiology; D005260:Female; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008266:Macula Lutea / Q000098:blood supply* / Q000502:physiology; D008297:Male; D011673:Pulsatile Flow / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000502:physiology*; D041623:Tomography, Optical Coherence / Q000379:methods* / Q000592:standards*