Researchers from the University of California San Diego have designed contact lenses that use naturally produced electrooculographic signals from our eyes to perform tasks like zooming in and out. The contacts use electrodes spread across the lens to act as muscles and are designed to expand when they receive an electrical signal from the eye.
When expanded the result is zoomed vision. This zoomed vision gives a person approximately 32 percent increased focal length. To de-activate the zoom all the person has to do is double blink.
The researchers are hopeful they can further expand this technology to one day create a fully functioning prosthetic eye.