Helmet-mounted choroidal laser Doppler flowmeter

Martial Henri Geiser; Fabrice Moret; Charles E. Riva

doi:10.1117/12.429325

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13 June 2001 Helmet-mounted choroidal laser Doppler flowmeter

Martial Henri Geiser, Fabrice Moret, Charles E. Riva

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Proceedings Volume 4263, Optical Diagnostics and Sensing of Biological Fluids and Glucose and Cholesterol Monitoring; (2001) https://doi.org/10.1117/12.429325
Event: BiOS 2001 The International Symposium on Biomedical Optics, 2001, San Jose, CA, United States

Abstract

A compact laser Doppler flowmeter (35x80x210mm³) for the measurement of subfoveal choroidal blood flow parameters (ChBF) was mounted on a helmet. This device allows the measurement of ChBF during dynamic exercises or in supine position, without the need for pupil dilatation. Its optical system is based on a Schlieren arrangement by which the surface of light collection and that of the illumination are spatially separated by an obscuration. The laser probing beam ((lambda) equals 790 nm, 100 (mu) W at the cornea) is focused at the fovea by having the tested subject look directly at the beam. Computer analysis of the photocurrent produced by the scattered light provides a relative measure of the mean blood velocity, number and flux of the red blood cells in the choriocapillaris. Measurements were performed to assess the reliability of the flow parameters measurements in normal volunteers: reproducibility and sensibility when subjects are sitting or standing; measurement of changes in ChBF in the case of isometric and dynamic exercises. Results demonstrate that this new helmet-mounted device provides data comparable to the conventional device. It allows for the first time, however, the continuous measurement of choroidal hemodynamics in humans during various types of exercises.

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Martial Henri Geiser, Fabrice Moret, and Charles E. Riva "Helmet-mounted choroidal laser Doppler flowmeter", Proc. SPIE 4263, Optical Diagnostics and Sensing of Biological Fluids and Glucose and Cholesterol Monitoring, (13 June 2001); https://doi.org/10.1117/12.429325

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