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.
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.