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. (Credit: Eric. J. Tremblay et al.)
Age-Related Macular Degeneration (AMD) is the leading cause of blindness in adults over the age of 50, and has no current cure, but scientists have developed a telescopic contact lens thin enough for practical use.
AMD effects the retina and causes vision to become so blurred and distorted as to effectively be blindness. The effects of AMD can be somewhat alleviated with a surgically implanted telescopic lens, but the procedure can be prohibitively expensive and the image quality isn't high.
An international team of researchers have developed a low-cost and non-invasive alternative -- a changeable contact lens.
Previous attempts got down to 4.4mm thick -- too thick for real world use. The new lens is just 1.17mm thick and achieves 2.8x magnification.
The proof-of-concept system was refined using a process called diamond turning. The lens has a 2.2mm surface where users can see with regular vision. The telescopic part of the lens is folded back on itself at the edges.
The light to be magnified enters the edge of the contact lens, is bounced four times inside the lens using patterned aluminium mirrors, then beamed to the edge of the retina. The mirrors magnify the image nearly three times while also correcting for chromatic aberration.
To switch between normal and telescopic vision, the unmagnified 2.2mm region of the contact lens has a polarizing filter that works in conjunction with a pair a glasses. The user can switch the polarizing state of the active, liquid crystal Samsung 3D spectacles to choose between normal and magnified vision.
The current telescopic contact lens is made out of PMMA, the gas-impermeable polymer that old, uncomfortable contact lenses were made of. To bring their lens to market, researchers will need to use the rigid gas permeable (RGP) polymers used in modern contact lenses.
And although the lenses are meant for people suffering from AMD, there is nothing preventing a person with healthy eyes wearing them for "superhuman" vision.