There has definitely been a lot of foreshadowing about eyes...but to what that means is very much ambiguous.
In mythology eyes were often windows to the spirit or weapons of magical might. As humans are creatures primarily focused by sight, we have always placed great significance on eyes and the loss of them. Eyes were also far more commonly lost in older times and the removal of eyes was often a form of punishment most cruel and horrific, but the self-removal was also considered an incredible sacrifice.
Many myths have beings who lose an eye or both eyes but often get greater gifts as compensation (mostly gods and supernatural beings, mortals often just had a worse time). In Egyptian mythology, Horus lost his eye in battle with his uncle/brother Set, and gained an eye made of moonbeams. The Eye of Horus is often associated with magic and protection (even Father Forthill has it tattooed on him!) In Greek mythology, the Cyclops' were giants only with a single eye and in the story of Perseus, the Grey Women also had a shared eye (which allowed them to see anywhere in the world). In Hinduism, the god Shiva is said to have a third eye in the middle of his forehead that burns whatever it looks at. In some versions, the belief is that he burned of the head of his own son Lord Ganesha in a fury and had to cut off an elephant's head to replace it (hence why Lord Ganesha has the head on an elephant). Shiva is also mirrored in Celtic mythology (there may have been some cross-cultural meetings) with Balor the Baleful (father of Ethniu) having either three eyes (on of which was the Evil Eye), one eye in the front of his head and one in the back (which was the Evil Eye) or sometimes just the single eye (rather like the Cyclops). Indeed, Celtic myths often intersected with Greek ones as there was some cross-cultural meetings and Balor was both associated with the Chimera (a beast with the head of a Lion, the body of a goat and the tail of a serpent who breathed fire - and was associated with storms), which the hero Bellerophron slays mounted on a winged Pegasus (the connection is Bellephron could mean "slayer of Belleros" which can mean Chimera, another being that spews flame or thunderbolts like Balor).
Obviously the tale of Odin is well known so I won't get into it here but it isn't surprising that many characters have eye related injuries or significant magical eye objects.
What I think is rather telling is that Butcher always references that people in the "darker" Mirror Mirror storyline will have goatees and eye patches. There are several characters with goatees but only two come to mind that are darker - Harry's Id and Justin DuMorne. In terms of eye patches the only character with one is Vadderung. I'll start another thread on this but maybe Butcher is laying some strong hints about the real motives of some characters.
