In the Middle East, it has been believed for ages that if a person looks at you with jealousy, anger, or hatred, they can influence your good luck in a negative way. There are even some translations of the Holy Bible that speak of the evil eye making people in the Middle East even more aware of protecting themselves from it.
Throughout the Hebrew and Islamic worlds, the evil eye is believed to be caused by strong minded individuals who glare upon another while thinking negative thoughts. In the modern day, this is usually interpreted as being a situation when someone stares at you with jealousy or anger in their hearts. For this reason, the Eastern evil eye charm is a popular, and really neat looking way, to protect ones self from any harmful effects of other people's state of mind.