Telescopic contact lens shows promise for AMD

Date: Feb-16-2015 An innovation that combines a telescopic contact lens with "smart" glasses

that look like normal eyewear looks set to be a great help to people with serious

vision problems, such as age-related macular degeneration.

The telescopic contact lens magnifies 2.8 times.
Image credit: EPFL

While current see-through wearable displays that improve poor vision are

available, they are clunky, impractical and people do not like using them in social

situations.

The team of academic and private developers behind the new zoomable lens and

glasses combination hopes that their invention - which is soon to enter clinical

trials - will be a more attractive option.

Estimates suggest that worldwide, there are around 285 million people with serious

vision problems, including age-related macular degeneration (AMD) - a painless eye

condition that results in gradual loss of central vision and is the leading cause of

blindness in older people in the Western world.

One of the developers of the new contact lens and glasses combination is Eric

Tremblay, an optics specialist at the Ecole Polytechnique Fédérale de Lausanne

(EPFL) - one of the two Federal Institutes of Technology of Switzerland. He worked

with Joe Ford at the University of California-San Diego, and other

collaborators.

Tremblay recently unveiled a new prototype of his telescopic contact lens - the

first of its kind - at the AAAS Annual Meeting in San Jose, CA, last week.

At the meeting, Tremblay also presented the smart glasses that are worn with the

telescopic contact lenses. They allow the wearer to control the zoom feature of the

contact lens with eye blinks. The glasses are designed to recognize winks and ignore

blinks.

"We think these lenses hold a lot of promise for low vision and AMD," says Tremblay. He adds:

"It's very important and hard to strike a balance between function

and the social costs of wearing any kind of bulky visual device. There is a strong

need for something more integrated, and a contact lens is an attractive direction.

At this point this is still research, but we are hopeful it will eventually become a

real option for people with AMD."

Telescopic contact lens magnifies 2.8 times

The telescopic contact lens magnifies 2.8 times. Since the first prototype in

2013, the developers have been fine tuning the lens material so it can be worn

comfortably over longer periods. They have also been developing eyewear accessories

that look attractive.

The contact lens is 1.55 mm thick and has a very thin reflective telescope

inside. Tiny mirrors reflect the light, expanding and magnifying viewed objects so

what you see is similar to what you can see through low magnification

binoculars.

The contact lenses are scleral lenses - they are larger and more

rigid than many of the types of contact lenses people wear today. They are made from

several pieces of precision cut plastic, aluminum mirrors and polarizing thin

films, held together with biologically safe glues.

One of the challenges the team has been working on is making the lens more

breathable so the eye has a steady supply of oxygen. They designed the lens so it

has tiny air channels about 0.1 mm wide.

The developers are still working on improving oxygen permeability and image

quality, which they hope to achieve as they refine and increase their understanding

of the mechanical and manufacturing processes.

Glasses and contact lens use polarized light to select magnification

People with AMD may only need the contact lens. But people without AMD may prefer

to have magnification "on demand," which is why the developers are also working on

the glasses.

The glasses look like normal eyewear except they have a small light source

detector that recognizes winks and ignores blinks of the wearer's eyes. They wink

with the right eye for magnification and with the left eye to restore normal

vision.

In the magnification mode, the glasses polarize light one way, and in the

normal mode, they polarize it the other way. The contact lens is designed so that

one type of polarized light uses the 1x aperture, and the other type of polarization

uses the 2.8x aperture. Thus, the wearer sees the view where the polarization of the

glasses matches that of the contact lens aperture.

The research is funded by the US Defense Advanced Research Projects Agency

(DARPA).

Meanwhile, Medical News Today recently learned that another team is

developing a new eyeglass material that will allow the wearer to make their eyeglasses become shaded on command. The

idea is to give users more control over when their glasses darken, such as while

driving or wearing a hat - situations that current transitional lenses do not cope

with very well.

Written by Catharine Paddock PhD

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.