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Biomed Opt Express. 2018 Apr 26;9(5):2351-2364. doi: 10.1364/BOE.9.002351. eCollection 2018 May 1.

Assessing blood vessel perfusion and vital signs through retinal imaging photoplethysmography.

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Photonics Engineering and Health Technology Research Group, Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
4Eyes Optometrist, Student Union Building, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.


One solution to the global challenge of increasing ocular disease is a cost-effective technique for rapid screening and assessment. Current ophthalmic imaging techniques, e.g. scanning and ocular blood flow systems, are expensive, complex to operate and utilize invasive contrast agents during assessment. The work presented here demonstrates a simple retinal imaging photoplethysmography (iPPG) system with the potential to provide screening, diagnosis, monitoring and assessment that is non-invasive, painless and radiationless. Time series of individual retinal blood vessel images, captured with an eye fundus camera, are processed using standard filtering, amplitude demodulation and principle component analysis (PCA) methods to determine the values of the heart rate (HR) and respiration rate (RR), which are in compliance with simultaneously obtained measurements using commercial pulse oximetry. It also seems possible that some information on the dynamic changes in oxygen saturation levels (SpO2) in a retinal blood vessel may also be obtained. As a consequence, the retinal iPPG modality system demonstrates a potential avenue for rapid ophthalmic screening, and even early diagnosis, against ocular disease without the need for fluorescent or contrast agents.


(100.0100) Image processing; (120.3890) Medical optics instrumentation; (170.0170) Medical optics and biotechnology; (170.3880) Medical and biological imaging; (170.5755) Retina scanning; (330.4300) Vision system - noninvasive assessment

Conflict of interest statement

The authors declare that there are no conflicts of interest related to this article.

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