title: Impact of motion-associated noise on intrinsic optical signal imaging in humans with optical coherence tomography.
abstract: A growing body of evidence suggests that phototransduction can be studied in the human eye in vivo by imaging of fast intrinsic optical signals (IOS). There is consensus concerning the limiting influence of motion-associated imaging noise on the reproducibility of IOS-measurements, especially in those employing spectral-domain optical coherence tomography (SD-OCT). However, no study to date has conducted a comprehensive analysis of this noise in the context of IOS-imaging. In this study, we discuss biophysical correlates of IOS, and we address motion-associated imaging noise by providing correctional post-processing methods. In order to avoid cross-talk of adjacent IOS of opposite signal polarity, cellular resolution and stability of imaging to the level of individual cones is likely needed. The optical Stiles-Crawford effect can be a source of significant IOS-imaging noise if alignment with the peak of the Stiles-Crawford function cannot be maintained. Therefore, complete head stabilization by implementation of a bite-bar may be critical to maintain a constant pupil entry position of the OCT beam. Due to depth-dependent sensitivity fall-off, heartbeat and breathing associated axial movements can cause tissue reflectivity to vary by 29% over time, although known methods can be implemented to null these effects. Substantial variations in reflectivity can be caused by variable illumination due to changes in the beam pupil entry position and angle, which can be reduced by an adaptive algorithm based on slope-fitting of optical attenuation in the choriocapillary lamina.
authors.affiliation: Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB, The Netherlands.
authors.forename: Michel M
authors.initials: MM
authors.lastname: Teussink
authors.affiliation: Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Tochigi, 321-8585, Japan.
authors.forename: Barry
authors.initials: B
authors.lastname: Cense
authors.affiliation: Diagnostic Image Analysis Group, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB, The Netherlands.
authors.forename: Mark J J P
authors.initials: MJ
authors.lastname: van Grinsven
authors.affiliation: Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB, The Netherlands.
authors.forename: B Jeroen
authors.initials: BJ
authors.lastname: Klevering
authors.affiliation: Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB, The Netherlands.
authors.forename: Carel B
authors.initials: CB
authors.lastname: Hoyng
authors.affiliation: Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Theelen
keywords: (110.4500) Optical coherence tomography; (170.2655) Functional monitoring and imaging; (170.3880) Medical and biological imaging; (170.4500) Optical coherence tomography; (330.5310) Vision - photoreceptors; (330.7331) Visual optics, receptor optics