A novel optical method for accurate blood oxygenation measurements independent of skin tone and other skin contributions

Blood oxygen monitors have become a common sight during the COVID-19 pandemic, as oxygen depletion in the bloodstream can be a warning sign of infection. Often placed onto a patient’s fingertip, these monitors rely on established photoplethysmography (PPG) technology which shines light on the skin and measures changes in how much of the light is absorbed to detect changes in blood oxygenation.
However, numerous studies have shown that these pulse oximeters are inaccurate when used on patients with darker skin tones, creating the potential for problematic false negative readings. Kimani Toussaint and colleagues have developed A novel optical method for accurate blood oxygenation measurements independent of skin tone and other skin contributions.

Market Opportunity

The onset of COVID-19 created the widespread need for rapid and accurate detection of irregular oxygen saturation levels. As low blood oxygen levels are known to be an early warning sign of coronavirus infection, this diagnostic information holds the potential to lead to better clinical outcomes and curb the number of resulting deaths. As a result, the past year-plus has seen significant interest in PPG technology such as the familiar fingertip devices, as well as an increased demand for smartwatches and other wearables that can accurately conduct on-demand PPG measurements.
Several studies, however, have reported that this optical technique overestimates the actual oxyhemoglobin saturation in patients with darker skin tones. This could lead to undiagnosed hypoxia that disproportionately affects Black and brown patients, leading to higher rates of death in these populations.

Innovation and Meaningful Advantages

The Toussaint Lab has invented a novel PPG technique to mitigate the issue of skin tone and color, as well as other related skin-based confounding effects such as wrinkles and tattoos. This technique uses radially polarized light generated from light-emitting diodes (LEDs).

Compared to other algorithms that exploit polarization to suppress skin effects and increase accuracy, Toussaint’s approach achieves single-shot, multiple polarization measurements. In addition, his approach uses LED light sources, a vortex wave plate, and a scientific CMOS camera for oxygen saturation measurements. By contrast, conventional devices use a single-element photodetector. The use of a scientific camera provides for improved spatial resolving capabilities because of its larger pixel resolution.

Collaboration Opportunity

We are seeking an investment or partnership opportunity to further develop this innovative technology.

Principal Investigator

Kimani Toussaint, PhD
Professor of Engineering
Brown University
Brown Tech ID #3175

IP Information

PCT Filed, Priority Date August 11, 2021


Brian Demers
Director of Business Development
Physical & Computational Sciences
Patent Information:
For Information, Contact:
Brown Technology Innovations
350 Eddy Street - Box 1949
Providence, RI 02903
Kimani Toussaint
Rutendo Jakachira
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