While normal contact lenses correct many people’s eyesight, they can’t improve the blurry vision of people with age-related macular degeneration (AMD), because correcting the eye’s focus cannot restore the central vision lost from a retina damaged by AMD. But, looking to change that is a team of DARPA-funded researchers from the US and Switzerland. The team, led by University of California San Diego Professor Joseph Ford has created a slim, telescopic contact lens that can switch between normal and magnified vision using a modified pair of liquid crystal eyeglasses. With refinements, they say that the system could offer AMD patients a relatively unobtrusive way to enhance their vision.

The switchable telescope contact lens is shown on the mechanical model eye.

As reported in the Optical Society’s journal, Optics Express, the new lens system developed by Ford’s team uses tightly fitting mirror surfaces to make a telescope integrated into a contact lens just over a millimeter thick. The center of the lens provides unmagnified vision, while the ring-shaped telescope located at the periphery of the regular contact lens magnifies the view 2.8 times.

To switch between magnified and normal vision, users wear a pair of liquid crystal glasses originally designed for viewing 3-D televisions. These glasses selectively block either the magnifying portion of the contact lens or its unmagnified center. The liquid crystals in the glasses electrically change the orientation of polarized light, allowing light with one orientation or the other to pass through the glasses to the contact lens.

The team created a life-sized model eye to capture images through their contact lens-eyeglasses system. They used a material for the lens called polymethyl methacrylate, known for robustness, because tiny grooves were needed in the lens to correct for aberrant color caused by the lens’ shape, designed to conform to the human eye.

Tests showed that the magnified image quality through the contact lens was clear and provided a much larger field of view than other magnification approaches, but refinements are needed before this proof-of-concept system could be used by consumers.

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