Lionel Tooley

 was a failed ventriloquist-turned-exterminator. On one of his jobs, he met a blind old woman. She directed Lionel and two others, the Sixth Doctor and Melanie Bush, to the attic, locking them in. They discovered a large alien insect that intended to steal their eyes, having already taken those of the old woman. Lionel, at last finding his ventriloquist ability, distracted the creature while the Doctor defeated it. (PROSE: The Eyes Have It)