When you're reading, looking at a map or squinting toward the horizon, your eyes adjust themselves involuntarily and instantaneously, thanks to tiny muscles inside the crystalline lens that can bend it and change its shape.
Like a camera coming into focus, this structure allows us to adjust the amount of light entering the eyes as it travels to the retina, where it is converted into an electrical signal that's transferred to the brain.
Researchers at the University California San Diego believe there may be a day - in the not so distant future - when glasses and contact lenses can read and respond to these eye movements, adjusting in real time to the electrical signals created by the muscles in the lens.
Inventions like "adjustable glasses" could follow, unleashing a new era of eyewear that would either organically adjust to someone's eye movements or allow wearers to control a lens by blinking, according to Shengqiang Cai, 37, a professor of mechanical and aerospace engineering at UC San Diego whose team is exploring new applications for soft robotics.
Imagine blinking twice to make a lens zooms in or out, or looking left, right, up or down and having a lens that followed.
Cai and his team believe they are well on their way, having recently created a soft robotic lens prototype that responds to the electric pulses - called electroculographic signals - that are generated by the eyes when they move.
"When you look at something near or far away your eye deforms its lens using muscle," Cai explained. "Our soft lens relies on a very similar mechanism - a simple deformation. We use a so-called artificial muscle, which is a responsive polymer, and we apply voltage and the material expands or shrinks just like a real muscle."
"Once the voltage is applied the response is very fast - almost instantaneous," he added.
Cai said his teams goal was to demonstrate a "human soft machine interface," that is, robots that are made from soft materials and capable of being connected to, or controlled by, humans.
Though research in hard robotics is much further along, the benefits of creating machines that are made from materials mimicking living organisms are many, according to robotics experts.
"Most traditional robotic systems are hard, that is, composed of metallic structures that require a computer to function," according to ScienceDaily, a website that aggregates news related to science research. "Soft robots are created with materials that don't use a rigid skeleton or electricity to provide mechanical strength. They are simpler to make and less expensive than hard robots, more capable of complex motions and safer to use around humans."
Because of their potential to squeeze past debris, researchers believe soft robots could be effective in search and rescue missions. The same abilities could also make them useful during invasive surgeries or in the development of flexible body armor.
Earlier this year, researchers at the Massachusetts Institute of Technology and Harvard University said they're developing a new type of flexible body armor for humans, one designed to cover joints such as knees and elbows. The material - which is as tough as the industrial rubber used to make car tires and garden hoses - was inspired by the durable, flexible membrane covering a lobster's joints and abdomen.
Cai said recent news reports seemed to suggest his team is close to finalizing a commercial contact lens that uses their technology, but he stressed that their two-year-old research remains in its early stages. There may come a day, he said, when similar technology that responds to signals generated by the body could be used to control prosthetic devices or soft robots that could alter their shape by deforming themselves.
"Compared to a company like Boston Dynamics, this field is still in a nascent stage and a lot of problems still need to be addressed," he said. "I would be very happy to see more creative ideas and applications that allow people to benefit from the development of soft robotics."