A non-invasive dual-wavelength retinal blood oxygen saturation measurement system based on the single-lens reflex camera

• 1、Department of Biomedical Engineering, College of Engineering, Peking University

Abstract：The measurement of retinal oxygen saturation level is of clinical significance. Currently, scientific-grade detectors are generally employed in both commercially developed instruments and laboratory prototypes that allow for the non-invasive detection of retinal oxygen saturation. However, these scientific-grade detectors are very expensive and to some extent it hinders the mass production and sales of the retinal oxygen saturation measurement instruments. In this study, a non-invasive retinal blood oxygen saturation measurement system is designed based on an adapted dual-wavelength fundus camera with the single-lens reflex (SLR) camera as the detector. Specifically, for the light source, green and red dual-wavelength narrowband LEDs are mutually interspaced in an annular arrangement. And the Canon 1500D SLR camera is used as the detector in the system for its ideal spectral response curves of the green and red channels. By extracting the corresponding retinal imaging information on the green and red channels, the functional blood oxygen saturation can be further calculated through a lab developed software. The method proposed in this study offers a new idea for the economic version of the retinal oxygen saturation measurement system. The experimental results show that the system is able to measure the oxygen saturation with good accuracy and repeatability, and it has the potential for further study and clinic applications associated with ophthalmic and systemic diseases.

Keywords： Retinal functional imaging Retinal blood oxygen saturation Single-lens reflex camera Bayer filter Fundus camera