In the recent past, we have seen quite a few solutions for Macular degeneration, a leading cause of legal blindness in adults over the age of 60. These solutions enhance the person’s existing vision and give them confidence to go out and about again and help them carry on with their lives more naturally ( see this and this).
Switchable telescopic contact lens, developed by researchers in the USA and Switzerland, provides the same enhancements but without the need of surgery. It magnifies the scene details by 2.8 times when paired with special spectacles.
The contact lens has a telescopic element that consists of tiny aluminum mirrors. This element sits right outside the central region of the lens that lets light in for normal vision. The mirrors bounce the light around four times within the ring before passing it on to the retina. The accompanying spectacles have polarizing filters that can be turned on so that the only light coming to the retina is through the spectacle+lens combo, thus magnifying the image 2.8x.
In the adjoining picture you can look at the results of images captured through the contact lens and optomechanical eye. (a) USAF resolution chart @ 1x. (b) USAF resolution chart @ 2.8x. (c) Outdoor image taken with optomechanical eye. (d) Outdoor image taken with contact lens and both apertures (1x + 2.8x). (e) Outdoor image taken with contact lens @ 2.8x.
This prototype lens is 8mm in diameter, 1mm thick at its center and 1.17 mm thick in the magnifying ring.
Since the lens would be worn by the user for an extended period of time, it was very important to make it “breathable” or make it suitable for use for more than 30 minutes. The researchers achieved the breathability by creating very tiny channels that let the oxygen flow through. The “gas-permeable versions of these lenses are being developed for clinical trials in November.
According to the researchers, the image quality provided by these lenses fell short of design goals but they have identified all the factors that would improve performance in the near future.
Hit the source links to read more about these telescopic contact lenses in greater detail.