Glucose levels in tears are five to ten times less concentrated than those found in blood, requiring more sensitive detection. However, based on the prototype, the lenses are expected to generate a reading once per second and to not need calibration.

“We’re now testing a smart contact lens that’s built to measure glucose levels in tears using a tiny wireless chip and miniaturized glucose sensor that are embedded between two layers of soft contact lens material.†Google said in a statement.

The contact lenses will be made up of two or three parts:

1) the glucose-sensing contact lens itself (expected to be the same size and material as standard commercial contact lenses, and not feel any different when worn).

2) a device that would communicate and power the lens, and

3) a display that would show the collected data. There is the possibility that 2) and 3) could be combined into the one device, such as a smart phone app or a portable computer.

Glucose sensor development is not new. Other wearable detection technology has had to factor in various issues such as the size or bulkiness of electronics, comfort of wear, power sources and battery life and needing an antenna to send information to a receiver. Other non-invasive alternatives to current methods like pricking are being prototyped such as saliva-based testing and temporary tattoos.

The project was announced last January but a patent was only recently secured for the product.

Working on the project is Google’s secret research arm Google[X] (known for other technologically ambitious projects such as Google Glass), and Novartis AG, a multinational pharmaceutical company. Google is working with Novartis’ Alcon eyecare division which has developed products such as Lucentis, a prescription medicine to treat diabetic macular oedema (DMA).

Novartis’ Chief Executive Joe Jiminez stated that he hoped the lenses will be commercially available in the next five years.