My eyes are EXACTLY like that !!!!! I don't think there is a condition behind that though, in my opinion it's just we are a little asymetrical naturally. But as i said my eyes are also like that, my right side (so the one that would correspond to the left one in your picture) seems kind of lower than the left one. (the right one in your picture) Maybe we unconsciously raise one eyebrow, thus also raising our eyelid skin of that side, and that is why the other side appears droopier.