The usage of eyes while communicating is Oculesics. This may include eye contact or the avoidance of eye contact. Eye contact is very important to form of non-verbal communication.
For example, the boss maintains longer eye contact than the employee. When a candidate goes for the interview if he maintains eye contact, it shows confidence. Avoidance of eye contact may also mean a person is guilty of telling lies. In a class, if a student is slouching, then as soon as the teacher stares the student will sit straight. Eyes can communicate a wide range of meanings.