Health and fitness minded individuals are looking for an easy way to keep their own tabs on vitals signs and parameters of medical care. Enter the biometric watch.
In a pair of papers published in The Optical Society's (OSA) open-access journal Biomedical Optics Express, groups of researchers from the Netherlands and Israel describe two new wearable devices that use changing patterns of scattered light to monitor biometrics: one tracks glucose concentration and dehydration levels, and the other monitors pulse.
The glucose sensor is the first wearable device that can measure glucose concentration directly but noninvasively, the authors say.
Both of the watches described in the two papers make use of the so-called "speckle" effect, the grainy interference patterns that are produced on images when laser light reflects from an uneven surface or scatters from an opaque material. When the material that is scattering the light is moving—say, in the case of blood flowing through the circulatory system—"the speckle pattern changes with changes in the flow," explained biomedical engineer Mahsa Nemati, a graduate student in the Optics Research Group at the Delft University of Technology in the Netherlands and the lead author of the Biomedical Optics Express paper on monitoring pulse. Those light variations are a valuable source of information, she says.
In the first paper, bioengineer Zeev Zalevsky of Israel's Bar-Ilan University and his colleagues describe a new wearable biometric system that uses the speckle effect to directly monitor the glucose concentration in the bloodstream, as well as the wearer's relative hydration level.
"Glucose is the holy grail of the world of biomedical diagnostics, and dehydration is a very useful parameter in the field of wellness, which is one of our main commercial aims," Zalevsky said.