In the before picture, her pupils are just barely visible.  The after picture shows a more normal upper eyelid position, with the upper eyelids cutting through the iris, well above the level of the pupil.

In some people, the upper eyelid position is too low because the muscle that holds the eyelid up is damaged.  In this patient's case, the muscle was fine, it was just too taxed by the weight of excess skin it had to hold up.