Cyclopia syndrome is a disorder which affects both Giants and Yetis in which in afflicted has only one eye. now Cyclops syndrome is a real thing where the embryonic prosencephalon fails to properly divide the orbits of the eye into two cavities the only problem is that none of them ever reach adulthood or even past a day (and yes the wiki link is quite disturbing). The question I want to know is could a diseases or disorder exist were the victim has only one eye but are still viable(as in are still capable of reaching adult hood)?
NOTE: magic does not exist in my story