Near Infrared Technology

The usage of light spectrum of different wavelengths to detect the blood sugar values is known as near infrared spectroscopy.
There is also a research going on the wireless glucometers like glucowatch called SymphonytCGM where the biosensor of type glucose oxidase send the data wirelessly to handheld device, but this has some problem like The longevity of the sensor, the accuracy of the device, the transdermal blood glucose variation (in terms of the time lag) and longitudinal adverse outcomes should further be explored.”

Wireless tech and telehealth systems are the most promising outcomes of the future non-invasive blood glucose meters.Here’s how: individual sensor results from the NIR non-invasive meter would be sent wirelessly to a mainframe system and within seconds the results from the NIR technology would be delivered via SMS mobile messaging to the patient. In this way, the technology could be downloaded by physicians and educators for assessing patient care and record-keeping, making it as competitive as the current CGM system without inserting a subcutaneous sensor.

References:
An article from the link http://asweetlife.org/elizabeth/blogs/products/scientists-getting-closer-to-the-end-of-painful-blood-glucose-testing/8789/