Technology has made it possible for us to create ways to store energy, as well as charge it without the need for an electrical power source. Researchers at Technological University (NTU) in Singapore applied that knowledge to smart contact lenses, which can be charged by tears.
NTU's Smart Contact Lenses
Smart contact lenses have been a concept seen in movies before where significant data is displayed close to its users' eyes. Real-life versions, however, are much harder to create because there are limited ways to power the device.
Since it is applied to something as sensitive as the eye, creators of such technology are wary of using certain power sources since they can be risky. Associate Professor Lee Seok Woo along with Ph.D. student Li Zongkang found a way around that.
The battery for the smart lens doesn't use any kind of metal. Instead, it is made up of biocompatible materials and has a glucose-based coating. As mentioned in Interesting Engineering, it reacts with sodium and chloride ions in the water inside the battery.
Both of the elements can be found in tears, which means that they can basically be charged while the user is wearing the lens. The battery has to be as thin as possible for comfortable wearing so it can still function like every other contact lens.
Despite the limitations, the smart lens is able to produce a current of 45 microamperes with a maximum power output of 201 microwatts. This is enough for the device to run for most of the day, which can be prolonged when it is charged with tears.
According to the report, the device can be charged for every 12 hours of use, providing one additional hour. While not in use, the device can be charged in a saline solution that contains glucose, potassium, and sodium ions for it to be charged.
The smart lens can get up to 200 charges in its lifespan. The researchers are already working on ways to increase the amount of electric current its batteries can discharge, as well as partnering with contact lens companies for distribution.
What Are Its Uses?
The smart contact lens is made to flash data on its viewer's corneas, which can display information about one's health. It can also be used to detect early signs of certain conditions like glaucoma or diabetes. These can then be sent to a smartphone.
Other companies have also been attempting to create this technology, some of which are made to measure cholesterol levels, enable vision enhancements, allow magnification, and even use the device for AR features like maps or lists, according to GoodRx.
Google tried to work on such a device that can track a person's blood sugar but decided to discontinue the project in 2018. Samsung and Sony, on the other hand, have already filed patents for lenses that include a camera. Sadly both companies have no updates to offer yet.
There are already other companies who are trying to bring their smart lenses to the market, just like the NTU researchers. However, the companies have not reached NTU's level of innovation regarding the batteries.
