Blue moon in your eye

I may have asked this before. What does "blue moon in your eye" mean as used in The Sophranos (HBO) theme song? (For a long time I thought the line was "boom boom in your eye" as in gunshot.)

Woke Up This Morning
Song by A3

You woke up this morning
Got yourself a gun,
Mama always said you'd be
The Chosen One.

She said: You're one in a million
You've got to burn to shine,
But you were born under a bad sign,
With a blue moon in your eyes.

If you ask me, it's just a pretty dumb lyric. "Blue moon" means "a long period of time", as in "once in a blue moon". So one could speculate that "a blue moon in your eye" means that "you" are special, one in a million, that kind of thing, but I'm thinking that it's just an example of superficially evocative but ultimately goofy poetry.

I take it back; I didn't read the entire lyrics. "Blue moon in your eye" does mean that "you're" special, once in a generation, "one in a million"--the author says exactly that.

Could be some kind of eye freckle?