The woman has a serious health problem:
This is by no means the only photograph out there showing this loss of control.
Writing for The Hill, Dr. John R. Coppedge observed:
It appears that she has a problem with her left sixth cranial nerve. That nerve serves only one function and that is to make the lateral rectus muscle contract. That muscle turns the eye in the direction away from the midline.
It comes out of the base of the brain and runs along the floor of the skull, immediately beneath the brain before coursing upward to the eye. Dysfunction of that muscle causes the striking picture of the eyes not aiming in the same direction and causes the patient to suffer double vision.
Like all things medical, there is a long list of potential causes but in my opinion the most likely one, based on Clinton’s known medical history is an intermittent lateral rectus palsy caused by damage to or pressure on her sixth cranial nerve.