title: Schlieren laser Doppler flowmeter for the human optical nerve head with the flicker stimuli.
abstract: We describe a device to measure blood perfusion for the human optic nerve head (ONH) based on laser Doppler flowmetry (LDF) with a flicker stimuli of the fovea region. This device is self-aligned for LDF measurements and includes near-infrared pupil observation, green illumination, and observation of the ONH. The optical system of the flowmeter is based on a Schlieren arrangement which collects only photons that encounter multiple scattering and are back-scattered out of the illumination point. LDF measurements are based on heterodyne detection of Doppler shifted back-scattered light. We also describe an automated analysis of the LDF signals which rejects artifacts and false signals such as blinks. By using a Doppler simulator consisting of a lens and a rotating diffusing wheel, we demonstrate that velocity and flow vary linearly with the speed of the wheel. A cohort of 12 healthy subjects demonstrated that flicker stimulation induces an increase of 17.8% of blood flow in the ONH.
authors.affiliation: University of Applied Sciences Western Switzerland, Institute of Systems Engineering, Sion 1950, Switzerland.
authors.forename: Martial H
authors.initials: MH
authors.lastname: Geiser
authors.forename: Frederic
authors.initials: F
authors.lastname: Truffer
authors.forename: Hugo
authors.initials: H
authors.lastname: Evequoz
authors.forename: Hafid
authors.initials: H
authors.lastname: Khayi
authors.forename: Benjamin
authors.initials: B
authors.lastname: Mottet
authors.forename: Christophe
authors.initials: C
authors.lastname: Chiquet
mesh_terms: D000328:Adult; D005260:Female; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D009898:Optic Disk / Q000098:blood supply* / Q000502:physiology; D010775:Photic Stimulation