Soft Contact Lens Which Can Zoom in When You Blink Twice Developed by Scientists

Researchers have developed a soft contact lens which can zoom in when you blink twice, enabling it to switch focus between objects at different distances.

Right now the device is a just a prototype that's a long way from being ready for use, but the scientists from the University of California San Diego say that in future, such a system could be used in visual prostheses, adjustable glasses, and remotely operated robotics in future, according to a study published in the journal Advanced Functional Materials.

The scientists utilized special electric signals generated by eye movements (known as electro-oculograms) to control the movement and change the focal length of the soft lens—which mimics the biological lens in mammalian eyes.

The device is made from layers of flexible polymers which expand when an electric current is applied, New Scientist reported. Conversely, when the current is removed, the lens contracts. These deformations alter the light that travels through the lens, adjusting the vision of the wearer.

Currently, the deformations are controlled by detecting electro-oculograms using five electrodes placed on the skin around the eye of the user. These electrodes measure differences in electric potential between the front and back of the eyeball as the user moves it around in different directions or blinks.

The scientists programmed the system so that when the user blinked twice, the lens would zoom in. If they did the same again, the lens would zoom back out.

"According to our knowledge, a soft tunable lens, whose position and focus length can be separately controlled by soft active material, has never been designed and constructed before," the authors wrote in the study.

Despite the success of the design, they stress that there are still many issues to be ironed out.

"Because the device shown in the current work is a proof-of-concept design, its performance can be further improved from many aspects," they wrote in the study. "First, in the current work, we used the commercially available monitoring electrodes attached to the skin, which were neither very flexible nor stretchable. It has been shown in previous studies, flexible and stretchable electrodes work much better for biosignal capture and processing."

"Second, in the current device, we did not realize the control of continuous motion of the lens," they wrote. "Third, as shown in the demonstration, the correction of the unexpected motions of the lens was not automatic, and the interference of human was required."

If these obstacles can be overcome, the researchers say that the system could be used as a new kind of vision aid, or implemented into a prosthetic eye.

"Even if your eye cannot see anything, many people can still move their eyeball and generate this electro-oculographic signal," Shengqiang Cai, lead author of the study, told New Scientist. "It could also be used as an external lens so that a human could control a camera with their eyes.

contact lens
The lens could be switched between near vision mode and distance vision mode due to the focal length change that was triggered by a double blink. University of California San Diego/Advanced Functional Materials/Wiley Online Library