A shape-shifting lens has been developed that alters its focal length when squeezed by an artificial muscle, a ring of polymer gel that expands and contracts in response to environmental changes, eliminating the need for electronics to power or control the devices.

Different polymer gels can be used to create a lens that responds to changes in acidity, temperature, light, electric fields or even certain proteins.

A lens designed to respond to a particular protein could be implanted into the body. As levels of the protein fluctuated throughout the day, the lens would change its focus, giving doctors a changing view of the area under observation.

I could also be useful for medical imaging; it could scan different depths in the body autonomously, based on conditions.