Researchers created new contact lenses inspired by the unique shape of a fish's retina. The fish-inspired lenses can automatically focus within milliseconds.

The new contact lenses can help treat a common eye disorder called presbyopia or farsightedness. People with this eye disorder find it hard to focus on nearby objects.

University of Wisconsin's Hongrui Jiang, who led the project, said that presbyopia affects over 1 billion people around the world and that half of these people do not receive sufficient correction.

Surgery, as well as traditional glasses and contact lenses, can improve eyesight, these options all come with an added cost - the loss of sensitivity, contrast and impaired night vision.

The big idea is to create new contact lenses that will adjust in accordance to the person's cornea. Moreover, Jiang's goal is to create new lenses that can bring back the youthful vision of the person.

The research team designed the lens as well as the sensors that are driven by algorithms. They also created minuscule electronic circuits that change the shape of the lens as well as a power source. All of these features are embedded in a supple, soft material that can fit on top of the eye.

"The sensors must be extremely small and capable of acquiring images under low-light conditions, so they need to be exquisitely sensitive to light," said Jiang.

The team's latest study focused on the image sensors' design, which mimics the uniquely shaped retina of the elephant nose fish. The biodesign reveals reflective sidewalls and a variety of structures that mimic deep cups. It collects light and intensifies specific wavelengths that enable the fish to evade predators even in muddy waters.

For their project, the researchers added thousands of minuscule finger-like glass lump light collectors, whose insides are aluminum-coated deep cups. When light hits the light collectors, the reflective sidewalls focus the light, thus enhancing the captured image.

The researchers took inspiration from the compound eyes of arthropods and other insects for another type of lenses. Their compound eyes are made of thousands of single microlenses that point to a different direction each, enabling them to focus on a specific part of an image or scene.

"Each microlens is made out of a forest of silicon nanowires," said Jiang.

For this type of lens, the research team created flexible artificial microlenses. They used a solar cell as the power source to collect electrons from sunlight and convert them into electricity. The network of nanostructures in the solar cell also help store energy.

The research was published in the journal Proceedings of the National Academy of Sciences.

Photo : Niek Beck | Flickr

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