New 'Telescope' Contact Lens Helps Patients with Macular Degeneration
Contact lenses help people across the world, correcting their eyesight and allowing them to see more clearly. Yet lenses don't help those suffereing from age-related macular degeneration (AMD), the leading cause of blindness among older adults in the western world. Now, scientists have developed a slim, telescopic contact lens that can switch between normal and magnified vision, helping those with AMD.
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Magnification aids that help AMD patients see haven't gained widespread acceptance. They're either bulky, spectacle-mounted telescopes that interfere with social interactions, or are micro-telescopes that require surgery to implant into the patient's eye. This new lens, though, might change how AMD patients see.
The new device uses tightly fitting mirror surfaces to make a telescope that has been integrated into a contact lens just over a millimeter thick. The lens itself has dual modality, which means that the center of the lens provides unmagnified vision while the ring-shaped telescope located at the periphery magnifies the view 2.8 times.
In order to switch back and forth between the magnified and normal vision, users need to wear a pair of liquid crystal glasses originally made for viewing 3D televisions. These glasses selectively block either the magnifying portion of the contact lens or its unmagnified center. How does it do it? The liquid crystals in the glasses electrically change the orientation of polarized light. This allows light with one orientation or the other to pass through the glasses to the contact lens.
"For a visual aid to be accepted, it needs to be highly convenient and unobtrusive," said co-author Eric Tremblay, one of the researchers, in a news release. The new device seems to meet that goal, giving users a way to see while at the same time remaining relatively "invisible."
That doesn't mean that the new lens is perfect, though. Refinements are needed before it can be used by consumers; for example, the grooves used to correct color have the side effect of degrading image quality and contrast. In addition, the material they used for the lens is not ideal for contact lenses; it's gas-impermeable, which limits wear to short periods of time.
That doesn't mean the team has given up. They're moving forward to perfect the design and hope to eventually make it available to those suffering from AMD.
The findings are published in the journal Optics Express.