If beating the right eye means that eyelid as a tic shakes her, then it's a neurological problem often due to lack of sleep or stress. It isn't anything serious, but it is convenient to go to the neurologist to diagnose and meet this annoying condition.
Movement, sense of brinco, involuntary eye press, attributed to various factors the most common is the anxiety or stress. ( the most advisable in these cases is to consult a physician, )