Is Doflamingo blind in one eye? There's a theory about that Doflamingo wears his iconic glasses because he's blind to his (IIRC) left eye. It was assumed because whenever his eyes were shown (quite rarely), it was actully always only the left one.

Is there anything we can know about it in canon? Any kind of disease of injury that would possibly, even theoretically justify it?
I guess i can assume that it is somehow of a correct theory, since in Doflamingo's past (as a little kid) you could see an arrow heading his way in the reflection of his sunglasses, as if they were heading for his left eye.
But if it even struck him is unknown.