Smart contact lenses — track your health through tears

Key points:

• Scientists at Nanyang Technological University in Singapore have invented a flexible, micrometres-thin battery that could power smart contact lenses

• Smart contact lenses could be used to send what a person sees to cloud-based data storage

• Smart contact lenses could be used to access augmented reality — monitoring the wearers’ health, correct vision and alert wearers’ to the onset of conditions such as diabetes and glaucoma

Contact lenses have offered people living with vision impairment the chance to correct their sight in a non-invasive way, however, much like phones and watches — the future is looking smart.

Scientists from Nanyang Technological University in Singapore have invented a flexible battery which is only micrometres thin — as slim as a human cornea — which can store energy when placed in a saline solution.

Existing technology for rechargeable batteries was not suited to how sensitive and vulnerable the human eye is — with coils, wires and metal serving as potential hazards — scientists have found a way to address this gap in health technology.

Associate Professor Lee Seok Woo, from NTU’s School of Electrical and Electronic Engineering, led the study and explained how scientists arrived at the idea.

“This research began with a simple question: ‘could contact lens batteries be recharged with our tears?’ There were similar examples for self-charging batteries, such as those for wearable technology that are powered by human perspiration,” he said.

Researchers found that the battery could be charged and recharged up to 200 times — for reference, a lithium-ion battery can withstand 300 – 500 charges. [Source: Shutterstock]

“However, previous techniques for lens batteries were not perfect, as one side of the battery electrode was charged and the other was not. Our approach can charge both electrodes of a battery through a unique combination of enzymatic reaction and self-reduction reaction.

“Besides the charging mechanism, it relies on just glucose and water to generate electricity, both of which are safe to humans and would be less harmful to the environment when disposed, compared to conventional batteries.”

Users could charge the smart contact lenses through a solution similar to a traditional lens case, as the glucose-based coating would react with the sodium and chloride ions in the saline solution surrounding it. The water contained in the battery would serve as the electricity current.

However, as Assoc/Prof Lee alluded to, human tears would also be capable of charging the device, as researchers were able to confirm through tests with a ‘tear-like’ solution.

The team showed off the efficacy of the tear-like solution.

Research co-first author Dr Yun Jeonghun said that the tear-based battery eliminates the two potential concerns that other forms of charging would pose.

“The most common battery charging system for smart contact lenses requires metal electrodes in the lens, which are harmful if they are exposed to the naked human eye,” Dr Jeonghun explained.

“Meanwhile, another mode of powering lenses, induction charging, requires a coil to be in the lens to transmit power, much like [sic] wireless charging pad for a smartphone.”

Further research is expected following a patent filed through NTU’s internal innovation and enterprise company, which will seek to commercialise the device when possible.

Which other forms of disability and personal aids do you think should be ‘smart-ified?’ Let the team at Talking Disability know your thoughts. Are your eyeballs off-limits or would you buy some smart lenses in the blink of an eye? We’d love to find out.