July 2018
Volume 59, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2018
Development of a binocular video-ophthalmoscope to compare parameters of heart beat induced blood volume changes between both eyes.
Author Affiliations & Notes
  • Ralf P Tornow
    Augenklinik, Universitaetsklinikum Erlangen, Erlangen, Germany
  • Folkert Horn
    Augenklinik, Universitaetsklinikum Erlangen, Erlangen, Germany
  • Jan Odstrcilik
    Department of Biomedical Engineering, Brno University of Techniology, Brno, Czechia
  • Radim Kolar
    Department of Biomedical Engineering, Brno University of Techniology, Brno, Czechia
  • Footnotes
    Commercial Relationships   Ralf Tornow, R&D RPT (P); Folkert Horn, None; Jan Odstrcilik, None; Radim Kolar, None
  • Footnotes
    Support  Deutsche Forschungsgemeinschaft Grant TO 115/3-1
Investigative Ophthalmology & Visual Science July 2018, Vol.59, 5859. doi:
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      Ralf P Tornow, Folkert Horn, Jan Odstrcilik, Radim Kolar; Development of a binocular video-ophthalmoscope to compare parameters of heart beat induced blood volume changes between both eyes.. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5859.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To measure parameters of pulsatile heart beat induced blood volume changes and to compare results between both eyes (amplitude, phase shift) within the same heartbeat with exact synchronization and high temporal and spatial resolution.

Methods : A binocular video ophthalmoscope was developed to acquire video sequences (25 fps, 250 frames) of both eyes simultaneously with exact synchronization. Each ophthalmoscope consists of an LED (575 nm) for illumination, an ophthalmic lens to generate an aerial image of the retina and a lens to image the aerial image to a CMOS camera (1.000 x 770 pixels). Acquired video sequences are registered offline to compensate for eye movements. Changing blood volume results in changing reflection of the retina. Higher blood volume results in lower reflection and vice versa. From registered video sequences, heart beat induced reflection (blood volume) changes can be measured in any user defined area of interest (AOI). The results can be compared between different positions in the same eye and also between corresponding positions in both eyes (e.g. ONH, vessels). For one entire cardiac cycle, the pulsatile reflection amplitude (PRA) is calculated as PRA = (Rmax-Rmin)/Rmax.

Results : The feasibility of this technique could be shown in a pilot study with 10 subjects. The wave form of the heart beat induced blood volume change shows a steep increase during diastole and a slower fall time during systole. PRA in vessel free area of the ONH is (5,9 ± 1,7) %. In the subjects of the pilot study, the difference in PRA between eyes is small (1,1 ± 1,2) % and the phase shift between both eyes is also small (< 40 ms). However, the figure shows the results of a subject with a phase shift of 80 ms between an AOI on a vessel (vein) of one eye compared to the corresponding area of the other eye and also to AOIs in the vessel free area of the ONH. To show the phase shift between positions, the pulses are normalized.

Conclusions : The binocular video ophthalmoscope allows measuring of parameters of the heart beat induced blood volume changes (resulting in reflection changes) with high spatial and temporal resolution and to compare results between different positions and between eyes. Differences in pulse parameters between left and right eye may be an early sign of beginning diseases like glaucoma. This method can be applied in a clinical setting.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

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