"When you completely lose an eye it is a difficult thing to let go of," he says. "The eye has an emotional attachment. It is a window to your soul."

Spence wore an eye patch for a while, which he says looked cool. But once he started thinking about having a camera in his eye, Spence got in touch with Steve Mann, a professor at the University of Toronto. Mann is one of the experts in the world of wearable computing and cyborgs -- organisms that blend natural and artificial systems.

"There are a lot of challenges in this," says Mann, "from actually building a camera system that works, to sending and receiving images, to getting the correct shape of the camera."

Even in the age of miniaturization, getting a wireless video camera into a prosthetic eye isn't easy. The shape of the prosthetic is the biggest limitation: In Spence's case, it's 9-mm thick, 30-mm long and 28-mm high.