Smart contact lenses have been developed that can be charged by human tears

Scientist Lee Seok-woo of Nanyang Technological University’s School of Electrical and Electronic Engineering was inspired by a scene from the movie “Mission Impossible” to create a battery for smart contact lenses. In the fourth part of the film, the agent uses contact lenses capable of recognizing faces and tracking eyes. Did you decide to make such technology a reality?

Lee understood that smart contact lenses needed safe and compact batteries. Together with the team, he developed a battery that can operate using a biocompatible saline solution, an alternative to traditional lithium-ion batteries with flammable materials. A “teardrop” battery can be charged chemically. The glucose coating on the battery interacts with the sodium and chloride ions in the saline solution, causing it to charge. After eight hours of chemical charging, the battery reaches 80% of full capacity and can operate for several hours during the day.

However, the battery’s current capacity and voltage remain low, producing around 0.3-0.6, which is significantly less than the standard AA battery voltage (1.5V). At this stage, the power is not enough to power data stores or connect to the Internet, but the team continues to work on improving the performance of the battery. The contact lenses themselves are extremely thin at 0.5mm, so the size and flexibility of these batteries is key to preventing wearer discomfort.