Robotic contact lenses that can zoom in and out with a simple blink of the eye have been created by scientisits.
The electric lenses can automatically switch between focusing on near or far away objects by tracking the wearer’s eye movements.
The sci-fi lenses are becoming a reality by mimicking the natural electric signals that occur in the human eyeball.
The breakthrough came by identifying an electric field around the human eye and differences in electrical voltage between the front and the back of the eye.
US researchers at California University realised that when a person moves their eyes to look around or blink, that electrical signal can be measured and tracked by the lenses.
Made from stretchy polymer films encasing salt water, they change their structure when an electrical current is applied to them.
Switching between long and short viewing is done by doing a double blink.
Lead researcher Shengqiang Cai said: “Even if your eye cannot see anything, many people can still move their eyeball and generate this electrooculographic signal.”
There are thought to be more than four million people in Britain who now wear contact lenses and rates are increasing.
Researchers believe it could help people who are both long and short sighted.
Looking down could cause the lens to focus on a page in a book, while looking up and ahead could lead the lens to adjust to focusing on a larger object further away.
Researchers say the system could be tuned to adapt to several blinks of an eye, allowing the lens to zoom in and out as necessary.
In the next few years the scientists plan to work out how the device could work without extra equipment before it can go on sale.
Currently the prototype only works with several electrodes placed around a person’s eyes and is hooked up to a rig.
