New watches use light to monitor body
Two new wearable devices have been developed that measure changing patterns of light to monitor glucose levels, dehydration, and pulse rate. One of the watch models is the first glucose sensor that can measure blood sugar directly but non-invasively.
Both devices use the grainy interference patterns that are produced on images when laser light reflects from uneven surfaces. For instance, when blood moves through the circulatory system, the speckle pattern of light changes with alterations in blood flow.
The glucose watch consists of a laser to generate a wavefront of light that illuminates a patch on skin on the wrist near an artery, plus a camera that measures change over time in the light that is backscattered off the skin. Blood glucose also exhibits certain light patterns in the presence of a magnet (which is attached to the device). The watch analyzes the changing patterns of light to measure glucose concentration.
Researchers expect a commercial version of the glucose monitor to be ready in two to three years. They currently are working with companies to integrate the pulse monitor into existing devices.