New Research: Contact Lenses with a Built-In Telescopic Zoom for Macular Degeneration

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zoom contact lens. Credit: Optics Express

Information about a new contact lens device, now in development (although not yet in clinical trials), that may benefit people with macular degeneration has been published in the July 1, 2013 issue of Optics Express. Optics Express, the international online journal of optics, is an all-electronic, open-access journal that publishes peer-reviewed articles emphasizing scientific and technological innovations in all aspects of optics and photonics.

About the Contact Lens Research

The study, entitled Switchable telescopic contact lens, was authored by Eric. J. Tremblay, Igor Stamenov, R. Dirk Beer, Ashkan Arianpour, and Joseph E. Ford, who represent the following institutions: the Department of Electrical & Computer Engineering, University of California, San Diego; Institute of Microengineering, école Polytechnique Fédérale de Lausanne, Switzerland; and the Pacific Science & Engineering Group, San Diego, CA.

Here is more information about the study from the article introduction:

We present the design and first demonstration of optics for a telescopic contact lens with independent optical paths for switching between normal and magnified vision. The magnified optical path incorporates a telescopic arrangement … to achieve 2.8x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

Age-related macular degeneration (AMD) is the leading cause of legal blindness for people over 55 in the western world, causing central vision loss in more than two million people in the US alone. Individuals with AMD and other degenerative eye disease can use magnifying visual aids to help distinguish details using the functional retina outside of the damaged central fovea. (Note: The macula is the small sensitive area in the center of the retina that provides clear central vision. The fovea is located in the center of the macula and provides the sharpest detail vision.)

Bioptic telescopes are the most common commercially available [distance] visual aids for low vision. These telescopes are mounted through spectacle lenses … [so] that the telescope can be brought into view by tilting the head. Bioptic telescopes are useful for some tasks, including driving, but many visually impaired people reject them due to their cosmetic appearance and interference in social interaction. Head-worn approaches also offer only a narrow field of view and require that the user turn their head directly towards the viewed scene.

We present an experimental demonstration of the contact lens mounted on a life-sized [mechanical] model eye and, using a pair of modified commercial 3-D television glasses, demonstrate electrically operated … switching between normal and magnified vision.

More about the Research and Development Phase of the Study

From a study summary in Medical Daily, entitled Telescope Eyes: Contact Lenses with a Built-In Zoom Developed for Macular Degeneration:

Contact lenses are wonderful for correcting vision in most people, but do little for those suffering from age-related macular degeneration (AMD), who often lose the ability to see small details like the contours of a face or letters on a page. To tackle AMD's special version of blurriness, an international team has designed contact lenses with a built-in zoom that could one day be used by people with AMD.

Rather than being out of focus, eyes with AMD lose the center of their visual field due to damage to the retina. However, peripheral areas of the retina, along with peripheral vision, remain intact.

If light entering the eye could be redirected onto these healthy areas, it might restore regular sight. At least this was the idea put forth in this study by Dr. Joseph Ford, an electrical and computer engineer at the University of California, San Diego.

He and a team of Swiss collaborators designed a contact lens that takes light as it hits the eye and magnifies it onto peripheral parts of the retina. They tested the lens on a life-sized model of a human eye and found that it could magnify the view by three times.

The zoom-in function for the contact lenses is always active, so in order to switch it on and off, a person would need to wear a special set of 3-D TV glasses made by Samsung. When turned on, liquid crystals in the glasses rearrange to block light to the magnifying portions of the contact lenses.

This concept could also be an alternative to the implantable telescope for AMD, which won approval from the Food and Drug Administration.

The Military Connection

The research was funded by the Defense Advanced Research Projects Agency (DARPA), via a larger program called Soldier-Centric Imaging via Computational Cameras. DARPA is the United States military think tank and research arm of the United States Department of Defense.

DARPA's scientific investigations "…span the gamut from laboratory efforts to the creation of full-scale technology demonstrations in the fields of biology, medicine, computer science, chemistry, physics, engineering, mathematics, material sciences, social sciences, and neurosciences." The telescopic contact lens project evolved from DARPA-funded research into vision enhancement devices for soldiers on the battlefield.

Current Limitations of the Research

Thus far, the telescopic contact lens has been tested only on a mechanical eye. Human clinical trials are scheduled to begin in November 2013. In addition, researchers are working to improve the resolution of the magnified image, which is more blurred than the "normal vision" portion of the contact lens.

Another issue is refining the plastic used in the prototype lens, as noted by the BBC Technology News:

"The most difficult part of the project was making the lens breathable," Dr. Tremblay told the BBC. "If you want to wear the lens for more than 30 minutes, you need to make it breathable."

Gases have to be able to penetrate the lens to keep the parts of the eye covered by the contact, especially the cornea, supplied with oxygen, he said.

Gas-permeable versions of the telescopic lens are being prepared that will be used in clinical trials in November, he said. Eventually it should be possible for those with age-related sight problems to wear the telescopic lenses all day.

VisionAware will continue to provide updates for this ongoing research as they become available.


Topics:
Medical Updates
Clinical Trials
Environmental assessment and modification

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