unequal pupils is called "anisocoria" and is most commonly caused by hjorner syndrome or a third nerve palsy. in both conditions an abnormality or asymmetry of the lid will likely be noted. with horner's the problem is on the side with the smaller pupil; with 3rd nerve palsy the larger pupil is the problem side. other causes coud be trauma vision problems or even familial.
what would cause unequal pupil size in my child's eyes?