The Colonization of Tiamat IV, p.10, footnote 18 wrote:From cyclopes, meaning one-eyed. Williamson states in his books that the Cyclopeans did have a single eye, but it is difficult to believe that such an advanced race would not have depth perception from the lack of stereoscopic vision. Of the surviving pictographs, the Cyclopeans are depicted as having one, large eye, which upon examination, could have easily been the visor of a protective helmet, much like our own pilots and astronauts use. The planetary environment was rather unstable in those days, so protective clothing is definitely a possibility.
From the movie
The Sheriff and the Satellite Kid (1979):
Eyewitness #1: A monster, a real monster! It was enormous, huge!
Eyewitness #2: It had one eye, right in the center of his forehead.
Reporter: Well, there you have it folks. According to eyewitnesses, some extraterrestrials or at least one has come to pay us a visit. And from the description we are dealing with a cyclops, reminiscent of the one-eyed giants of the Greek mythology. But that remains to be seen.
A moment later, this guy shows up in his beekeeper outfit (Bud Spencer):