While the title is a bit misleading - we're not talking about a fully functional bionic eye - researchers at Northwestern University and the University of Illinois at Urbana-Champaign have developed a camera that could conceivably function as the light sensor in an artificial eye. The Northwestern team was led by civil and environmental engineering professor Yonggang Huang. The work was reported in a recent issue of the journal Nature. There's also a video on the National Science Foundation's website.
What makes this feat notable is that Huang's team is the first to figure out how to make a hemispherical camera - one in which the light sensor's shape mimics the curvature of a sphere. Until now, light sensors have been made using rigid, planar (flat) materials that cannot be formed in the shape of a sphere. If you've ever tried to gift-wrap a baseball without any wrinkles in the paper, you know what I mean.
A fully functional bionic eye using this technology is still quite a ways off, though. One has to tackle the not-so-small problem of figuring out how to interface the sensor with the brain – involving more than a million neurons that carry electrical signals from the back of the eye to the brain.
More immediately, though, the eye-like camera has several distinct advantages over the old, planar technology. Images taken with an eye-like camera will be brighter and distortion-free.
If you're interested in how animal eyes evolved, there's a nice article and video on the PBS website.