Harbisson wears the "eyeborg" headset to overcome a visual impairment called achromatopsia, which means he sees the world in shades of grey. The eyeborg turns colours into sounds, allowing him to "hear" them and meaning he qualifies as a cyborg, or cybernetic organism - a living being with both natural and artificial parts. "Feeling like a cyborg was a gradual process," he said. "First, I felt that the eyeborg was giving me information, afterwards I felt it was giving me perception, and after a while it gave me feelings. It was when I started to feel colour and started to dream in colour that I felt the extension was part of my organism."