Why is 1 eye bigger than the other? Why does the eyebrow of the smaller eye sit higher than the other eyebrow? (Photo)

You appear to have left upper eyelid ptosis (droopy eyelid) which forces your eyebrow to raise in order to assist in lifting the droopy eyelid. The solution would be left upper eyelid ptosis surgery. See an oculoplastic surgeon for evaluation.

Your asymmetry is due to a left upper lid droop. The left upper lid is closing and you are arching your left brow to compensate. When you get tired your ability to compensate lessens and the eye will appear smaller. I would recommend seeing an oculoplastic surgeon to be evaluated for possible surgery. Best of luck.