Extreme Tech has the details on the contacts that let you see like an eagle:
The center of the lens allows light to pass straight through, providing normal vision. The outside edge, however, acts as a telescope capable of magnifying your sight by 2.8x. This is about the same as looking through a 100mm lens on a DSLR. For comparison, a pair of bird-watching binoculars might have a magnification of 15x.
To create a 1.17mm-thick telescope, the researchers — led by Joseph Ford of UCSD and Eric Tremblay of EPFL — had to be rather creative. The light that will be magnified enters the edge of the contact lens, is bounced around four times inside the lens using patterned aluminium mirrors, and then beamed to the edge of the retina at the back of your eyeball. The mirrors magnify the image 2.8 times, but also correct for chromatic aberration, resulting in a surprisingly high fidelity image. To switch between normal and telescopic vision, the central (normal, unmagnified) region of the contact lens has a polarizing filter in front of it — and then the wearer equips a pair of 3D TV spectacles. By switching the polarizing state of the spectacles (a pair of active, liquid crystal Samsung 3D specs in this case), the user can choose between normal and magnified vision.
Pictures of the lenses – and what the world looks like through them – at the link.