Biometric watches that use light to check your glucose level

Researchers have designed wearable devices that use changing scattered light patterns to track your glucose level as well as pulse monitoring.

Scientists from Netherland and Israel have published details of this latest invention in Biomedical Optics Express. Author claims that their new devices are error resistant and wearer can get an accurate result even if he wears it while on motion.

Both these watches work on speckle effect theory by producing grainy interference patterns on images when laser light is scattered from an uneven surface. When the blood flowing through veins scatter these laser light the speckle pattern also changes with motion. Mahsa Nemati, the main author of the report, explained that those light variations are valuable source of information.

The first paper explains how the watch works to read the glucose level in the blood stream of the wearer. The device consists of a laser that generates a beam of light which illuminate a patch of skin on the wrist near wearer’s artery and a camera measures changes over time in the backscattered light to the skin. Glucose has the property to exhibit Faraday Effect. The magnet attached to the device produces a magnetic field which causes glucose molecules to alter polarization of wavefront and this influence results in speckle patterns. (many subject-verb agreement problems in this para)

By analysing this change in pattern we get direct reading of glucose concentration in blood. Muscle weakness caused by dehydration alters signal strength and hence we can find out relative dehydration level also. Scientists are now putting their effort to make it error free by proper calibration and motion cancellation procedures which reduces sensitivity.

The team expects that commercial version will hit the market within 2-3 years.

The second paper gives an account of how the pulse monitoring device works on the wearer irrespective of his movements. Researchers have discovered that a couple of pixels from images are sufficient enough to measure pulse rate. The research shows for the first time that speckle pattern generated from a flowing liquid will have pulsation properties in spite of motion inducing factors.Cost of the device may not be too high as sophisticated optics is not used. Device may be non-contact or away from the sample, which is another advantage.

Currently the team is working with companies to integrate their technique into existing sensors for potential clinical use.

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