Irish literature about mythology is quite complex. The author of this book does a quite engoyable telling of each story portraying the gods. After the story he explains what the texts that have been recovered say and then makes inferences. A good example is: The Theft of Gaibhneann’s Cow and the Birth of Lugh. His telling basically states that Cian the sun god went to Gaibhneann’s forge to have a sword made. Gaibhneann agreed but only if Cian would watch his cow. At the end of the day when the sword is finished he returns to pick up the sword and as he walks inside Balar (god of drought) sneaks up and takes the cow. Cian chases Balar but Balar makes it to his castle across the water. So Cian asks Manannan to help him cross the water and he agrees except he demands half the plunder. Now to get to the cow he needs to get inside the keep where the Balars daughter is. But no man is allowed to enter so Cian dresses as a woman and goes in to then shack up with Eithne (the daughter) and she bears three children. Mad Balar throws Cian and the children and the cow out the window and Cian manages to save one child and the cow. Upon returning to Mananna he asks for his payment and Cian gives him the child and returns the cow.
However some original texts indicate the cow itself is Balars daughter…. Interesting. Along with that another says that the sun god Cian is apparently the divine cow herder entrusted with protecting the cow and should something happen to it he must make it right. Further along in the story Cian seeks help from Mananna yet original texts only assume that the sea god helped Cian because he is the natural enemy of Drought. So it is clear to see that major things in these stories are related like water and drought or earth and fire and that they oppose each other throughout the stories.
My personal analysis may not lead to a correlation between the one eye monsters exactly except for the fact they are both bad. However if one knows the story about how Zeus came to power it is quite similar in its portrayal.