These smart contact lenses are charged with your tears

A new battery should be able to charge smart contact lenses with tears. (Source: NTU via YouTube)

If, like me, you have problems with your eyesight – my -4 diopters say hello – then you generally have the choice between glasses and contact lenses at the optician.

Now, in the world of VR and AR technology, glasses are almost the only thing to be found, but in recent years research has also been working on smart contact lenses.

A first prototype was shown in 2022 in the form of the Mojo Lens, which can, among other things, show you performance data during sports.

The problem with smart contact lenses: How should the battery be charged without posing a potential health risk to the human body? After all, traditional batteries use metallic parts that definitely shouldn’t come near the eye.

Researchers at NTU Singapore (Nanyang Technological University) now want to have found the answer to the puzzle.

In a research paper, the team around Assoc. Prof. Lee Seok Woo talks about a flexible battery form that does not contain any such metals. Instead, the scientists are relying on a biocompatible solution with a glucose-based coating.

Link to YouTube content

This glucose coating can react with sodium and chloride ions found in water, which are also found in our tears.

The battery itself is thinner than a millimeter and, according to experiments conducted, can produce around 45 microamperes of current and an output of 201 microwatts.

This means that a smart contact lens should be able to last for around a day, depending on the application scenario. In addition, the lenses are safe for people and the environment due to the battery base made of water and glucose, as the research paper continues.

Instead of tears, a classic saline solution for charging is also conceivable, as is already used to clean conventional contact lenses.

In total, the flexible battery should be able to withstand around 200 charging cycles before it needs to be replaced. The NTU team is currently working on increasing this number as well as the amount of electricity supplied – so it will still take some time before it is ready for the market.

I’ll leave it up to you where you get your tears from – but for legal reasons I would like to point out that if the worst comes to the worst, you should use something you produced yourself.

Smart contact lenses – is this the future of augmented reality? What would you use such lenses for? Let us know in the comments!