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Smart contact lenses are getting closer

(a) Schematic showing the mechanism of intraocular pressure sensing. (b) Schematic of the experimental set-up for wireless intraocular pressure sensing. (c) Photographs of the sensor transferred onto the contact lens worn by a bovine eyeball (left) and a mannequin eye (right). Scale bar, 1 cm.

Advances in smart materials, that is materials that can sense a variety of parameters and react on those, continues at a fast pace. The idea of embedding sensors in a contact lens is not new, Google announced back in January 2014 a project for a contact lens that would be able to detect glucose in the tears and partnered with Novartis to bring the lens to market by 2019. Recently Novartis chairman declared that whilst they are still interested in the project they would consider unlikely to have a product on the market in the promised timeframe. The problem is that the content of glucose in the tears is minimal and does not exactly correlate the the amount of glucose in the blood. Along with this there is the issue of power, common to many biosensors.

Other teams have been working on embedding sensors in contact lenses, with glucose measurement as a first goal, but also with the idea of embedding a camera for a real POV (Point Of View) recording -like Samsung.

Now in an open paper, published on Nature Communications, a team of South Korean researchers at Ulsan National Institute of Science and Technology, is reporting on the design of a smart contact lenses that embeds a glucose sensor, based on micro-fluidic technology, and a pressure sensors, based on silicon elastomer embedding graphene wires. The data harvested by the sensors are stored locally in the lenses and can be retrieved using external power through the radio signals that is sent to the lens by the reading device, through an induction coupling mechanisms (similar to the one being used to recharge an electrical toothbrush).  This reading mechanisms solves the issue of powering, since the smart material making up the lenses can harvest data with no need for a battery.

The accuracy of the glucose detection from tears is quite good, according to the researchers, however it does not solve, yet, the issues of the accuracy in correlation between the glucose content in tears and the glucose content n the blood (which is what really matters for checking on diabetes…).

The detection of eye pressure values is accurate and can be a good indicator of glaucoma.

Overall, it is interesting to see the progress being made in the area of biosensors, although more advances, and experimentation, are required.  I am confident that in the next decade we will start to see a widespread use of biosensors, including smart contact lenses.

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